WINE & WINE PROCESS
What is ―WINE‖? Species and Varieties of the Grape Cultivation The Steps of ―WINEMAKING‖ Harvesting Crushing Juice Separation Must Treatment Fermentation a) Primary Fermentation b) Secondary Fermentation c) Fermentation for White Wine d) Fermentation for Red Wine e) Fermentation Considerations f) Conditions for The Fermentation g) Control of Fermentation Postfermentation Treatment
Malo-lactic Fermentation Laboratory Tests Clarifications Fining Preservation Filtration Centrifugation Refrigeration Ion Exchange Heating
The Colour of Wine What are those pigment? Structural stability Red or White? Colourful Cues Bottling Choosing Bottles and Corks Before Bottling Bottling Keeping
Aging of Wine Containers for Aging Aging
Special Wines Sparkling Wines a) Tank Fermentation b) Bottle Fermentation c) Carbonation Fortified Wines Fruit Wines Flavoured Wines The Uses of Wines Aperitif Red Dinner Wines White Dinner Wines Sparkling Wines Table Wines Dessert Wines Serving Temperatures for Wines Health and Wine
What is “WINE” ?
Wine is fermented grape juice. Wine can be made from grapes, fruits, berries etc. Most wine, though , is made from grapes. And no matter what the wine is made from, there must be fermentation, that is, that sugar be transformed into alcohol.
If the amount of alcohol is relatively low, the result is “wine”. If it is high, the result is a "distilled liquor“, something like gin or vodka.
There are red wines, pink wines (also known as "rose" or some-times "blush") and white wines. Red wine result when the crushed grape skin pulp and seeds of purple or red varieties are allowed to remain with juice during fermentation periods. Pink / rose wine can be produced by removing the non-juice pumace from the must during fermentation. White wines can be made from pigmented grapes by removal of skins, pulp and seeds before juice fermentation.
Wines might be "fortified”,"sparkling”, or "table“.
Wines are termed still or sparkling depending upon the amount of CO2 they contain. The carbon dioxide may be formed naturally during fermentation or may be added artificially.
The term light wine is also used to describe wine having alcohol content from 5 - 10 %.
Species and Varieties of the Wine Grape
The thousands of grape varieties that have been developed, with 5,000 reported for Vitis vinifera alone, differ from one another in such characteristics as colour, size, and shape of berry; juice composition (including flavour); ripening time and disease resistance.
They are grown under widely varying climatic conditions,and many different processes are applied in producing wines from them. All of these possible variations contribute to the vast variety of wines available.
European Wine Grapes ( Vitis Vinifera ):
V. vinifera, probably originating in the Caucasus Mountains, is the principal wine-producing plant, with most of the world's wine still made from varieties of this species. The high sugar content of most V. vinifera varieties at maturity is the major factor in the selection of these varieties for use in much of the world's wine production. Their natural sugar content, providing the requisite substrate for fermentation, is sufficient to produce a wine with alcohol content of 10 percent or higher; wines containing less alcohol are unstable because of their sensitivity to bacterial spoilage.
The moderate acidity of ripe grapes of the V. vinifera varieties is also appropriate for wine making; the fruit has an acidity of less than 1 percent (calculated as tartaric acid, the main acid in grapes) and a pH of 3.1 to 3.7 (mildly acid). Malic acid is also an important acid; only small amounts of citric acid are present.
A third factor attracting winemakers to this grape is its tremendous range in composition.
The pigment pattern of the skin varies from light greenish yellow to russet, pink, red, reddish-violet, or blue-black; the juice is generally colourless, although some varieties have a pink to red colour, and the flavour varies from quite neutral to strongly aromatic.
Native Wine Grapes (Vitis Lambrusca- Vitis rotundifolia ):
The species V. labrusca and V. rotundifolia seldom contain sufficient natural sugar to produce a wine with alcohol content of 10 percent or higher, and additional sugar is usually required.
Their acidity at maturity is often excessive, with a low pH. Varieties of these species usually have distinctive flavours. The flavours of V. labrusca, owing to methyl anthranilate and other compounds, are considered too pronounced by some consumers.
This flavour, especially prevalent in wines made from the Concord-type varieties, is commonly called "foxy“.
Native Wild Grapes (Vitis Muscadinia):
These are grapes such as Muscadine (Scuppernong), Fox and Frost grape. They are extremely sharp tasting due to their high acid content and have a strong assertive to pungent flavor and aroma. They are also lower in sugar than other grapes. This class of grape can be distinguished from others by the fact they do not grow in clusters, but rather, as separate berries.
The grapevine, although primarily a temperatezone plant, can grow under semi-tropical conditions. It is not adapted to the cooler parts of the temperate zone, where growing seasons may be too short to allow the fruit to reach maturity or where low winter temperatures (less than -7°C) may kill the vine or its fruitful buds. V. vinifera is more susceptible to damage from winter conditions than V. labrusca.
Climate strongly influences the composition of mature grapes.
A major cause of the variation among grapes from different areas is the differing quantities of heat received by the vines during the growing season.
Other important factors include differences in night and day temperature, hours of exposure to sunlight, and soil temperature.
Grapes begin their growth cycle in the spring when the average daily temperature is about 10°C. To reach maturity , they require a certain amount of heat above 10°C during the growing season. This amount of heat, called the heat summation, is calculated by totalling the value of average daily temperatures over 10°C for each day of the growing season.
A heat summation of about 1,800 is required for successful growth.
If the heat summation is less than required , the grapes will not ripen ; they will reach the end of the growing season with insufficient sugar and too much acidity.
Factors influencing the heat summation of a vineyard and, therefore , grape composition include exposure (in Europe, best from the east):
air drainage (preferably from the slopes to the valley), soil temperature (above 10°C during the growing season), soil moisture content (not too dry at any time and not waterlogged for more than short periods).
Such cultivation practices as weeding and pruning may also influence the mature fruit composition. Although the composition of the soil has an influence on soil temperature, root penetration, water-holding capacity and vine nutrition, its effect on the quality of wine, varying from region to region, is poorly understood.
Some grapes will require only a little dilution with water to get its sharp acidic flavor under control. Others will require none at all.
Not only does the high acid level of the wild grapes require dilution but their excessive, strong flavor demands it as well.
Sugar may need to be added to the juice in some cases. Sugar is what the yeast ferments to make alcohol. When the fermentation is done the sugar is gone. When there is not enough sugar for the yeast, there will not be enough alcohol in the wine. Certainly in the case of wild grapes sugar will be in short supply and marginally so with some native wine grapes. Sugar will need to be added to these mixes. But, in the case of European wine grapes only rarely is sugar needed.
How do we know when water and/or sugar needs to be added to the juice, and if so, How much do we need to add ?
GETTING THE RIGHT MIX
For measuring and controlling acidity we can use an acid testing kid and for measuring and controlling sugar levels you can use a hydrometer.
Both come with complete directions and are relatively easy to use.
Acid Level Adjustment
You would start by taking an acid level reading of the juice to determine where you are at.
Sugar Level Adjustment
Once the acidity level is correct you then will want to check the sugar level and adjust it if necessary. The hydrometer has a "Potential Alcohol" scale which tells you how much alcohol can be made with the sugars that are currently in the juice. You will want to shoot for a potential alcohol level somewhere between 9 and 13 percent.
If the acid level is found to be twice as high as needed, then you would add equal amounts of water to cut the level in half.
If the acid level is only 10 percent too high you would then only need to add 10 percent water.
Almost always the European wine grapes will provide enough sugar naturally. The native wine grapes will usually need a little sugar and the wild grapes will need
significant amounts of sugar.
The Steps of “WINEMAKING”
Winemaking, or vinification, is the production of wine, starting with selection of the grapes or other produce and ending with bottling the finished wine. Although most wine is made from grapes, it may also be made from other fruit or non-toxic plant material. Mead is a wine that is made with honey being the primary ingredient after water.
Winemaking can be divided into two general categories: Still wine production (without carbonation) Sparkling wine production (with carbonation)
The science of wine and winemaking is known as oenology (in American English, enology)
Fresh and fully ripened wine grapes are preferred as raw material for winemaking.
The resulting sugar deficiency may be corrected by direct addition of sugar or by the addition of a grape juice concentrate. Grapes that are allowed to reach full maturity on the vine or that are partially dried by exposure to sun after harvesting are high in sugar content as a result of natural moisture loss. A beneficent mould, Botrytis cinera, may also be employed to hasten moisture loss.
These grapes are used to produce sweet table wines.
Special methods employed to produce sweet table wines include the addition of sulphur dioxide, the use of small fermenting vessels during processing, or the use of cool temperatures - the objective being to stop the fermentation before all the sugar is fermented.
Because of its effect on grape composition, proper timing of the harvest is of great importance.
Premature harvesting results in thin, low-alcohol wines; very late harvesting may yield high-alcohol, low-acid wines.
Harvesting may be completed in one picking or in several.
The grape clusters are cut from the vine and placed in buckets or boxes and then transferred to larger containers (large tubs in Europe, metal gondola trucks in California and elsewhere) for transport to the winery.
Mechanical harvesting systems, based on shaking the berries from the clusters or on breaking the stems, are widely used in California, Australia, France, and elsewhere. At the winery the grapes may be dumped directly into the crusher or may be unloaded into a sump and carried to the crusher by a continuous conveyor system.
In modern mechanised wine production, the grapes are normally crushed and stemmed at the same time by a crusher-stemmer, usually consisting of a perforated cylinder containing paddles revolving at 600 to 1,200 revolutions per minute.
The grape berries are crushed and fall through the cylinder perforations; most of the stems pass out of the end of the cylinder. A roller-crusher may also be used. Ancient methods of crushing with the feet or treading with shoes are rare.
When red grapes are used to produce a white juice, as in the Champagne region of France, crushing is accomplished by pressing. Red grapes are sometimes introduced whole into tanks, which are then closed. The resulting respiration in the fruit, consuming oxygen and producing carbon dioxide, kills the skin cells, which lose their semi-permeability, allowing easy colour extraction. There is also some intracellular respiration of malic acid. This respiration process is slow and in warm regions may result in wines of low colour and acidity and distinctive odour.
Juice Separation :
When the juice of white grapes is processed or a white wine is desired, the juice is usually separated from the skins and seeds immediately after crushing. Occasionally, to increase flavour extraction, the white skins may be allowed to remain in contact with the juice for 12 to 24 hours; however, this procedure also increases colour extraction, sometimes undesirably.
Two main procedures are employed to separate the juice from the solids.
Much of the juice may be drained off by placing the crushed grapes in a container having a false bottom and often false sides. This juice is called the free run juice, and the mass of crushed grapes is called the must, a term also used to refer to the unfermented grape juice, with or without skins.
More commonly, the crushed grapes are placed in a press. A horizontal basket press, applying pressure from both ends, is gradually supplanting the traditional basket press. Continuous screw-type presses are also employed, especially for drained pulp.
The Willmes press, widely employed for white musts, consists of a perforated cylinder containing an inflatable tube. The crushed grapes are introduced into the cylinder, and the tube is inflated, pressing the grapes against the rotating cylinder sides and forcing the juice out through the perforations. Several pressings may be made without the extensive hand labour required for basket presses.
Continuous presses are practical for production of red wines, in which skins, seeds, and juice are all fermented together. Separation of the juice is simplified because fermentation makes the skins less slippery, and the amount of free run juice obtained is, therefore, much greater than for unfermented musts. Separation of the less slippery solids from the juice by pressing is also simplified.
The drained pomace (crushed mass remaining after extraction of the juice from the grapes), from white or red fermentations, may be used to provide distilling material for production of wine spirits.
Water is usually added, the fermentation is completed, and the low-alcohol wine is drained off. The pomace may be further washed and pressed or may be distilled directly in special stills.
Must Treatment :
White musts are often turbid and cloudy, and settling is desirable to allow separation of the suspended materials.
Such measures as prior addition of sulphur dioxide and lowering of the temperature during settling help prevent fermentation and allow the suspended material to settle normally.
In many areas wineries centrifuge the white must to remove the solids. In this process a strong pulling force is created by circular motion. Musts are sometimes pasteurised, inactivating undesirable enzymes that cause browning. The addition of pectin-splitting enzymes to the musts to facilitate pressing is uncommon. Bentonite, a type of clay, may be added to musts to reduce total nitrogen content and facilitate clarification.
There is renewed interest in the pre-fermentation heat treatment of red musts to extract colour and deactivate enzymes. This process, when performed rapidly at moderate temperatures and without undue oxidation, may be particularly desirable in the production of red sweet wines, employing short periods of fermentation on the skins; it is also suitable for use with red grapes that have been attacked by the parasitic fungus Botrytis cinerea, which contains high amounts of the polyphenol oxidase type of enzymes that cause browning.
At this point the mix--which we can now call a "Must"-should be in an open fermentation vessel of some type. You will then want to add to the must the following ingredients: Yeast Nutrient: add at the rate of 1 teaspoon per gallon. This is not yeast, but rather, an energy source for the yeast which will be added later. Pectic Enzyme: add at the rate of 1/8 teaspoon per gallon. This is used to aid in the clarification of the wine, and in the case of red wines, to help break down the pulp so more flavor can be extracted.
Potassium Bisulfite: add at the rate of 1/16 teaspoon per gallon or 1/4 teaspoon for every 4 gallons. This is used to sterilize the must, to kill all the wild molds, bacteria and yeast that come with the fresh grapes. Over a 24 hour period the Potassium Bisulfite will sterilize the juice and then dissipate into the air. Only cover the fermentation vessel with a light towel during the waiting period. Yeast can then be added after waiting 24 hours. If the yeast is added before the Potassium Bisulfite leaves it will kill the yeast as well. Just sprinkle the yeast onto the surface of the must at a rate of 1 package for every 5 gallons.
It is important that during the 24 hour waiting period before the yeast is added that the fermentation vessel is only covered with a light towel, maybe an old t-shirt.
This is to make sure that the Potassium Bisulfite which needs to escape and leave the vessel is not trapped by a lid or a heavy covering of some kind.
Conditions for the Fermentation :
The quality and quantity of primary and secondary substances produced during fermentation, basically depend on the conditions happening during this process. It is extremely important for the must to be in the best possible condition before the fermentation begins, in particular, it is essential it is not oxidized.
For this reason, it is very important the fermentation of the must starts as soon as possible, soon after the normal operations of stabilization, decanting and clarification.
During this phase the must is in fact particularly sensitive to the attacks of bacteria, spoilage caused by microbial activities and oxidation. For this reason, it is essential the period of prefermentation should be as short as possible and the must to be properly protected by adding sulfur dioxide.
This practice allows in fact to do all the operations of decanting and clarification of the must without taking the risk of spoilage.
Moreover, it is of fundamental importance the fermentation is done according the typical times for this process, a time which - according to the type of must, the operations done for its stabilization and the quality of the grapes - can be from 5 to 15 days. An excessively slow fermentation can in fact favor the development of secondary substances responsible for ―ordinary‖ aromas and taste as well as an excessive quantity of volatile acidity.
On the contrary, in case the fermentation is too fast, this will cause an excessive increasing of temperature and a loss of aromas - which will be lost with the huge quantity of carbon dioxide released during the process - with the result of obtaining an ordinary wine having no pleasing organoleptic qualities. Temperature plays a fundamental role for fermentation. According to the type of wine to be made, it is essential the temperature is kept constant within a specific range, as we will see later.
A too low temperature - usually lower than 15° C (59° F) - inhibits in fact the start and the process of fermentation, while increasing the risks of oxidation or, in case of red wines, an insufficient extraction of color. Too high temperatures will cause a too rapid fermentation with the risk of obtaining a coarse wine and pretty ordinary, lacking of any quality of finesse. An excessively high temperature causes the interruption of fermentation as well as the death of yeast.
Temperature is also important during the adding of selected yeast to the must. It is important the temperature of selected yeast is as equal as possible to the one of the must to which they will be added, as an excessive difference of temperature can cause the death of most of the yeast, therefore making useless this operation. Finally, it is good to remember selected yeast must be added to the must before the beginning of the fermentation process.
The Primary Fermentation :
Usually within 12 hours of adding the yeast (sometimes 24) you will see the fermentation activity begin by way of small patchy areas of foam on the surface of the must. These patches will progress into a layer of foam that can get as high as 4 or 5 inches over the next 2 to 3 days. During this time the fermentation vessel should be covered only with a thin cloth towel. It is important that the fermentation be able to breath during these first few days of fermentation. You will also want to stir the must on a daily basis with a stirring paddle so as to break up any dried formation of solids that may rise to the top.
During the primary fermentation of wine, the two grape sugars, glucose and fructose are converted to alcohol (ethanol) by the action yeast. The by-products of primary fermentation are aromas and flavours, the gas carbon dioxide, and heat.
The production of heat during fermentation (i.e. it is an exothermic process) means that during fermentation the temperature of the fermentation vessel will rise, and will require action on the part of the winemaker to cool it down.
White wine fermentation is usually conducted in the range of 8-19OC, and red wine fermentions typically are allowed to run at between 25 and 32oC. At temperatures higher than this, there can be a loss of desirable aroma and flavour compounds, and unattractive aroma characters in the spectrum of caramel, burnt or cooked characters can be produced. There are many types of yeast, but two closely related types known as Saccharomyces cerevisiae and Saccharomyces bayanus are the ones that are responsible for fermentation.
These species of yeast are encouraged to conduct the fermentation because they:
Are alcohol tolerant. That is, they can continue to ferment sugars to alcohol even during the latter stages of fermentation when the sugar is low but the alcohol content is high. Can establish a viable population in an environment of high sugar (190-270 grams per litre) and high acidity. Are strong and consistent fermenters even at cold temperatures. They ferment quickly and only stop when all the grape sugars have been utilised. Otherwise we would be buying sweet low alcohol wines. Are more tolerant to sulfur dioxide than other yeasts and bacteria. They produce wine like aroma and flavour characters
In white winemaking the juice is usually inoculated with yeast following its clarification. The most common type of inoculation is that using an active dried yeast culture.
Yeasts are freeze dried and stored in vacuum packed tins by yeast supply companies ready for use. The winemaker then re-hydrates the yeast in warm water bringing them out of their state of suspended animation. The hydrated yeast is then added to the juice.
Another less interventionist approach is to let nature take its course. The grapes have a bloom that contains active cells of Saccharomyces cerevisiae.
After juicing the grapes these grape yeast cells and other yeast cells picked up from the winery equipment then start to convert the grape sugars to alcohol. This type of fermentation is variously called natural, indigenous or spontaneous fermentation.
The advantages of winemaker inoculation are:
Choice. Many different strains of Saccharomyces cerevisiae have been isolated and have different properties. Some produce very fruity (estery) aromas, others produce more neutral characters. Some ferment better at colder temperatures than others. Consistency. All strains are selected for their ability to meet the general necessary criteria given above. This maximises the chances of clean and complete fermentations occurring.
The advantages of spontaneous inoculation are:
Better Mouthfeel. Many commentators' report that they feel that spontaneous fermentation promotes better mouthfeel in wines.
That is, the wines are thought to be softer and creamier than those made using single strain starter cultures. This suggestion however has not been conclusively demonstrated scientifically.
The rational for the suggestion is that the natural yeast flora on the grape is genetically heterogeneous, i.e. consists of multiple strains and that this is the reason for the improved mouthfeel.
Cost. Spontaneous fermentation costs nothing to initiate.
The disadvantages of spontaneous fermentation are:
Lag time :
Yeast cells increase in number by division. One becomes two, two become four, four become eight etc. The initial numbers of yeast cells in an un-inoculated juice are by nature low. Dividing from a low initial base of cells means that it takes longer for fermentation to become active. A wait of 3-4 days is typical. In large commercial wineries where the vintage is planned to work like clockwork, with tanks becoming free just when purchased fruit is to arrive at the weighbridge, the uncertainties of spontaneous fermentation present excessive risk. When inoculating, the winemaker adds about 5 billion cells per litre. Quite a head start over spontaneous fermentation.
Higher probability of spoilage:
In theory this should be a problem but in practice it rarely is. Sometimes other spoilage yeasts and bacteria take advantage of the ecological void caused by the shortage of active yeast cells in the early stages of spontaneous ferments.
In practice this can be avoided by ensuring that the acidity of the juice is sufficiently high. Saccharamyces cerevisiae is more tolerant to acidity and sulfur dioxide than most other organisms, and winemakers use these facts and engineer the juice environment to favour its growth over the undesirable microbes.
The Secondary Fermentation :
Around the 5th or 6th day of fermentation you will want to transfer ("rack") the must into a clean fermentation vessel leaving any pulp and sediment behind. If you are making red wine you will want to press the pulp at this time to extract all of the juice and then discard the pulp. If you are making white wine you will simply transfer ("rack") the wine to the new container.
A thin cloth towel should no longer be used, but instead an air-lock should be attached to the new vessel. The air-lock is used to allow gases to escape from the fermentation vessel without letting anything bad back into the must. You can use the same type of fermentation vessel that you used for the primary fermentation so long as an air-lock can be attached to it.
Some winemakers prefer to use a carboy or similar type container for their secondary fermentations.
During the secondary fermentation the yeast will be finishing up its activity and the solids will be settling out. After the fermentation has completely stopped and you have verified with the hydrometer that it has completed, you will want to add another dose of Potassium Bisulfite to help preserve the wine's flavor and color while it is clearing
The clearing process can take several weeks, sometimes months. You will want to rack the wine off the sediment every month or so while you are waiting. As an option you can speed up the clarification process by treating the wine with finings after the fermentation has completed.
Fermentation Considerations :
* Temperature plays an extremely vital role in the
fermentation process. If the fermentation temperature is too cool, the yeast may not be invigorated enough to ferment. It will simply remain in the juice, dormant. If the fermentation temperature is too warm, the yeast may ferment fine, but the flavor of the wine will usually suffer. This is because of the increased production of unwanted enzymes by the yeast and the possible growth of microorganisms that thrive in warmer temperatures. The optimum temperature for a fermentation is 72 degrees, but anywhere between 70 and 75 will do fine.
* Throughout the fermentation process you will need
to transfer the wine off the sediment into a clean container.
This is a process that is referred to as "racking" in most wine making books. This should be done at the end of the primary fermentation.
It should also be racked after the secondary fermentation as well as right before bottling the wine.
* It is also important to understand that once the
wine's fermentation activity has stopped that it also needs to be given time to clear as well before bottling. Yeast is a silty substance that can take up to 2-4 additional weeks to clear up once the fermentation has stopped.
Fermentation of White Wines:
For the fermentation of white wines it will be used a must from which will be eliminated the skins soon after having crushed the grapes. In order to have a better fermentation and a more stable wine, it will also be appropriate to clarify and decant the must in order to eliminate any solid substance before starting fermentation, as already mentioned in past articles published in DiWineTaste.
The primary goal of fermentation of the must destined to the production of white wine is to keep finesse and quality of aromas, a result which is mainly obtained with a scrupulous control of the temperature and by keeping it from 16° and 20° C (60°-68° F). This range of temperatures will in fact allow the optimal development of aromas, a slow transformation of sugar and an excellent production of alcohol.
Lower temperatures will make fermentation difficult and can also stop the whole process, therefore favoring the oxidation of the must.
Higher temperatures will make fermentation excessively active, with the result of losing most of refined aromas, therefore obtaining a pretty coarse and ordinary wine. For this reason, during the fermentation of white wines, it will be scrupulously controlled the temperature by making sure it does not go outside the correct range.
Fermentation is a process developing heat, therefore it is very likely the temperature easily raises above 20° C (68° F), in particular during mild seasons. The best method to cool the fermentation tank down, in case there are no automatic systems for the control of temperature, is to run cold water along the sides of the tank. In case temperature gets too low, it can be used the same method by using lukewarm water.
Another method consists in heating the room where are found the fermentation tanks. It is not recommended to warm the must by plunging electric heaters or similar systems, because this can cause the excessive heating of the must in contact with the heater therefore developing “burnt” tastes.
Fermentation of Red Wines :
For the fermentation of red wines will be used a must in which will be allowed skins to macerate, an essential operation allowing the extraction of color. It will be the extraction of color and polyphenolic substances, one of the primary goals in the alcoholic fermentation of red wines. Coloring substances contained in the skins can be easily extracted at higher temperatures, and the higher the temperature, the better the extraction of coloring substances and polyphenolic substances, in other words, a red wine fermented at a higher temperature will have a fuller structure and body.
It is of fundamental importance to control temperature, by making sure it does not go outside the optimal range, which for red wines is from 25° and 30° C (77°-86° F). This temperature allows the production of red wines with good quality, a good extraction of color and polyphenolic substances, as well as a good balance between these two qualities.
Temperatures lower than 20° C (68° F) will make difficult the extraction of coloring substances from the skin, therefore it is always recommended to not allow temperature to get so low. Temperatures from 20° and 25° C (68°-77° F) will allow a moderate extraction of coloring substances, however not enough for the optimal extraction of polyphenolic substances, with the result of obtaining a light wine and with a light body.
Temperatures included in this range are recommended for light red wines, not destined to aging and to be consumed within the year. Temperature higher than 30° C (86° F) make wines rich in polyphenolic substances as well as robust, however the fermentation could cause the development of taste with a pronounced ―herbaceous‖ quality and, in case it is not properly controlled, this can also interrupt the fermentation process.
Such high temperatures are sometimes useful for the fermentation of grapes having little coloring substances, such as Pinot Noir.
In this specific case, after the first racking, that is the separation of the skins from the wine, it is recommended to complete fermentation at a temperature of about 20° C (68° F), in order to allow an optimal development of aromas and the best condition for malolactic fermentation.
Control of Fermentation:
The normal conditions for wine home making do not always allow scrupulous controls on fermentation because specific laboratory tools are not usually available. However, also in wine home making it is indispensable to properly control the process of fermentation in order to ensure the best possible result. Of all the controls usually done on fermentation, two of them are considered to be of fundamental importance: the control of temperature and the control of density.
These two controls are indispensable and they will be done on a daily basis, carefully writing down the results in a record, in order to get a trend of the fermentation and the changes of the two values according to time.
The control of temperature is very easy to do: it will be enough to detect it from the fermentation mass by using a thermometer. In case temperature is outside the optimal range for the wine to be made, it will be necessary to properly correct it by using the methods discussed above. The control of density is very simple to do as well and it allows the verification of the good progressing of fermentation and, in particular, to realize when it is interrupted before the normal end. The control of density can be easily done by using a normal densimeter, the same used for the control of grape's ripeness.
During fermentation, the density of the must progressively diminishes, until reaching a value from 0.990 to 0.995. Values greater than 1 mean the presence of sugar, therefore the fermentation is not completed yet.
In case density gets stabilized on a value greater than 1, it means the fermentation is stopped and it is then necessary to restart it as soon as possible.
The most common cause is a variation of temperature and therefore it will be necessary to take proper action. This phenomenon is properly detected by controlling the density as, after the fermentation is stopped, carbon dioxide continues to develop from the tank - just like the normal progressing of fermentation - and when it completely stops it is usually to late and no remedy is useful.
Postfermentation Treatment :
With appropriate must composition, yeast strain, temperature, and other factors, alcoholic fermentation ceases when the amount of fermentable sugar available becomes very low (about 0.1 percent).
Fermentation will not reach this stage when (1) musts of very high sugar content are fermented, (2) alcohol-intolerant strains of yeast are used, (3) fermentations are carried out at too low or high temperatures, (4) fermentation under pressure is practiced.
Fermentation of normal musts is usually completed in ten to thirty days. In most cases, the major portion of the yeast cells will soon be found in the sediment, or lees. Separation of the supernatant wine from the lees is called racking. The containers are kept full from this time on by "topping―, a process performed frequently, as the temperature of the wine, and hence its volume, decreases.
During the early stages, topping is necessary every week or two. Later, monthly or bimonthly fillings are adequate.
Normally the first racking should be performed within one to two weeks after completion of fermentation , particularly in warm climatic regions or in warm cellars , as the yeasts in the thick deposit of lees may autolyse (digest themselves), forming off-odours. Early racking is not required for wines of high total acidity i.e., those produced in cool climatic regions or from high-acid varieties. Such wines may remain in contact with at least a portion of the lees for as long as two to four months, permitting some yeast autolysis in order to release amino acids and other possible growth factors favouring growth of lactic-acid bacteria. These bacteria then induce the second (or malolactic) fermentation.
Malo-lactic Fermentation :
Enologists have known for some time that young wines frequently have a secondary evolution of carbon dioxide, occurring sometime after the completion of alcoholic fermentation. This results from malolactic fermentation, in which malic acid is broken down into lactic acid and carbon dioxide. The fermentation is caused by enzymes produced by certain lactic-acid bacteria.
Flavour by-products of unknown composition are also produced during this fermentation.
Malolactic fermentation is desirable when new wines are too high in malic acid, as in Germany, or when particular nuances of taste and flavour are desired, as in the red wines of Burgundy and Bordeaux in France. In other regions, some producers may encourage malolactic fermentation, and others may discourage it, depending upon the particular character desired in the wine. In all regions, this second fermentation is somewhat capricious. One product, diacetyl (a flavour and aroma agent), is apparently beneficial at low levels and undesirable at higher levels.
At low temperatures, malolactic fermentation proceeds slowly, if at all. German cellars are often equipped with steam pipes, raising the temperature to encourage this fermentation. The bacteria may fail to grow because of a deficiency or complete absence of essential amino acids. Most lactic-acid bacteria growth can be inhibited by the presence of 70 to 100 milligrammes per litre of sulphur dioxide.
Excessive malolactic fermentation may produce wines too low in acidity (flat tasting) or with undesirable odours (mousy, sauerkraut, or diacetyl). Such faults may be prevented by earlier racking, filtration, and addition of sulphur dioxide.
Laboratory Tests :
Whether the wine is aging in tanks or barrels, tests are run periodically in a laboratory to check the status of the wine. Common tests include °Brix, pH, titratable acidity, residual sugar, free or available sulfur, total sulfur, volatile acidity and percent alcohol.
These tests are often performed throughout the making of the wine as well as prior to bottling. In response to the results, a winemaker can then decide if more sulfur needs to be added or other slight adjustments before it is bottled.
°Brix is a measure of the soluble solids in the grape juice and represents not only the sugars but also includes many other soluble substances such as salts, acids and tannins, sometimes called Total Soluble Solids (TSS) . However, sugar is by far the compound in greatest quantity and so for all practical purposes Brix is a measure of sugar level. The level of sugar in the grapes is important not only because it will determine the final alcohol content of the wine, but also because it is an indirect index of grape maturity. Brix (Bx for short) is measured in grams per hundred milliliters, so 20Bx means that 100ml of juice contains 20gm of dissolved compounds.
There are other common measures of sugar content of grapes, Specific gravity, Oechsle (Germany) and Beaume (France).
The French Beaume (Be for short) has the benefit that one Be gives approximately one percent alcohol. Also one Beaume is equal to 1.8 Brix, that is 1.8 grams of sugar per one hundred milliliters. This helps with deciding how much sugar to add if the juice is low in sugar; to achieve one percent alcohol add 1.8 grams per 100 ml or 18 grams per liter. This is the process of chaptalization, legal in some countries illegal in others. However, perfectly acceptable for the home winemaker. Generally, for the making of dry table wines a Bx of between 20 and 25 is desirable, this is equivalent to Be of 11 to 14.
A Brix test can be ran either in the lab or out in field for a quick reference number to see what the sugar content is at. Brix is usually measured with a refractometer whilst the other methods use a hydrometer.
Generally, hydrometers are a cheaper alternative. For more accurate use of sugar measurement it should be remembered that all measurements are affected by the temperature at which the reading is made, suppliers of equipment generally will supply correction charts.
Volatile acidity test verifies if there is any steam distillable acids in the wine. Mainly present is acetic acid but lactic, butyric, propionic and formic acids can also be found.
Usually the test checks for these acids in a cash still, but there are new methods available such as HPLC, gas chromatography and even enzymatic methods. The amount of volatile acidity found in sound grapes is negligible. It is a by-product of microbial metabolism. It's important to remember that acetic acid bacteria require oxygen to grow.
Eliminating any air in wine containers as well as a sulfur dioxide addition will limit their growth. Rejecting moldy grapes will also prevent possible problems associated with acetic acid bacteria. Use of sulfur dioxide and inoculation with a low-V.A. producing strain of Saccharomyces may deter acetic acid producing yeast. A relatively new method for removal of volatile acidity from a wine is reverse osmosis. Blending may also help—a wine with high V.A. can be filtered (to remove the microbe responsible) and blended with a low V.A. wine, so that the acetic acid level is below the sensory threshold.
Some wines deposit their suspended material (yeast cells, particles of skins, etc.) very quickly, and the supernatant wine remains nearly brilliant.
This is particularly true when 50-gallon wooden barrels, which have greater surface-to-volume ratio than larger containers, are employed. The rough interior of wooden cooperage facilitates deposition of suspended material.
Other wines, particularly in warm regions or when large tanks are used, may remain somewhat cloudy for long periods. Removal of the suspended material during ageing is called clarification. The major procedures involved are fining, filtration, centrifugation, refrigeration, ion exchange, and heating.
The most common preservative used in winemaking is sulfur dioxide. Another useful preservative is potassium sorbate.
Sulfur dioxide :
Sulfur dioxide has two primary actions, firstly it is an anti microbial agent and secondly an anti oxidant. In the making of white wine it can be added prior to fermentation and immediately after alcoholic fermentation is complete.
If added after alcoholic ferment it will have the effect of preventing or stopping malolactic fermentation, bacterial spoilage and help protect against the damaging effects of oxygen. Additions of up to 100 mg per liter (of sulfur dioxide) can be added, but the available or free sulfur dioxide should be measured by the aspiration method and adjusted to 30 mg per liter.
Available sulfur dioxide should be maintained at this level until bottling.
For rose wines smaller additions should be made and the available level should be no more than 30 mg per liter. In the making of red wine sulfur dioxide may be used at high levels (100 mg per liter) prior to ferment to assist stabilize color otherwise it is used at the end of malolactic ferment and performs the same functions as in white wine. However, small additions (say 20 mg per liter) should be used to avoid bleaching red pigments and the maintenance level should be about 20 mg per liter.
Furthermore, small additions (say 20 mg per liter) may be made to red wine after alcoholic ferment and before malolactic ferment to over come minor oxidation and prevent the growth of acetic acid bacteria.
Without the use of sulfur dioxide, wines can readily suffer bacterial spoilage no matter how hygienic the winemaking practice.
Potassium sorbate is effective for the control of fungal growth, including yeast, especially for sweet wines in bottle. However, one potential hazard is the metabolism of sorbate to geraniol a potent and very unpleasant by-product. To void this either the wine must be sterile bottled or contain enough sulfur dioxide to inhibit the growth of bacteria. Sterile bottling includes the use of filtration.
Filtration is another ancient practice, and early filters consisted of rough cloth-covered screens through which the wine was poured. Modern filter pads are made of cellulose fibres of various porosities or consist of membrane filters, also in a range of porosities.
The pore size of some filters is sufficiently small to remove yeast cells and most bacterial cells, but filters operate not only because of pore size but also by a certain amount of adsorption. Diatomaceous earth-filter aids, commonly added to the wine during filtration, increase the functional life of a filter by retarding pore clogging.
Centrifugation, or high-speed spinning, used to clarify musts, is also applied to wines that are difficult to clarify by other means. This operation requires careful control to avoid undue oxidation and loss of alcohol during the process.
Refrigeration aids wine clarification in several ways. Temperature reduction often prevents both yeast growth and the evolution of carbon dioxide, which tends to keep the yeast cells suspended. Carbon dioxide is more soluble at lower temperatures. A major cause of cloudiness is the slow precipitation of potassium acid tartrate (cream of tartar) as the wine ages. Rapid precipitation is induced by lowering the temperature to a range of -7 to -5°C for one or two weeks. If the resulting wine is filtered off the tartrate deposit, tartrate precipitation will not usually cause clouding later.
Ion Exchange :
Another method of tartrate stabilisation is to pass a portion of wine through a device called an ion exchanger. If this ion exchanger is charged with sodium, it will replace the potassium in potassium acid tartrate with sodium, making a more soluble tartrate. Usually, if the potassium content of the blend of either treated or untreated wine is reduced to about 500 milligrammes per litre, no further precipitation will occur. Exceptions may occur, however, and to be safe, tartrate and potassium contents and pH are included in the calculation. The use of ion exchange is illegal in several countries.
Many wines contain small amounts of proteins that may cause clouding either by precipitation or by reacting with copper or other metals to form aggregates that in turn form clouds. The use of bentonite removes some protein, and protein adsorption is increased if the wine is warm when fined.
Pasteurisation at 70 to 82°C also can be used to precipitate proteins, but in modern practice this process is seldom employed to aid clarification. During "heat stabilization", unstable proteins are removed by adsorption onto bentonite, preventing them from precipitating in the bottled wine.
The Colour of Wine :
Wine colour, particularly red, is one of wine's most outstanding features and a strong cue to wine style. On the surface it is quite simple, red wines contain red pigments, termed anthocyanins, and white wines don't.
Big wines have alot of colour, and appear almost black with a purple tinge, whilst a light Beaujolais is quite easy to see through and clearly bright red. However, it is possible to go a bit more in depth into the subject and I will try to do so here, starting by explaining some basic terms and eventually venturing into the complex world of tannins!
What are those pigments?
Red wine, blueberries and petunia flowers all contain anthocyanins, the most common red plant pigments of all. Anthocyanins belong to a group of secondary plant metabolites that are called flavonoids, and are almost ubiquitously synthesized by plants in at least some tissues, particularly under stressful conditions. (Beetroot, by the way, owe their intense colour to betacyanins, a group of similar, but different, compounds).
The flavonoids also include some of the pre-cursors of tannins, but more on that later..., and they are part of an even larger group of compounds thermed phenolics. All phenolics, including anthocyanins, contain at least one phenolic ring (benzene group or aromatic ring are alternative terms). Anthocyanins have three, and there are very very tiny differences in the structure of anthocyanins compared to other "neighbours" such as the yellow flavonols, that endow them with the ability to tickle our perceptions with different wavelengths (or colours).
Anthocyanins are almost always stored as glycosides (see glycoside section for further information) since the glycoside-lacking anthocyanidins are very unstable and can rapidly convert into other colourless forms, reversibly and irreversibly. Together with a range of different sugars and various acyl-groups (fancy name for acids) attached to different positions in a myriad of combinations, several hundred different anthocyanin forms are produced by plants.
The structure of anthocyanins, the presence of various other compounds (particularly copigments, fancy name for compounds that can interact physically with anthocyanins) and the pH of the solution that they are in, all have an impact on colour absorption and hence colour perception. For example, wines with a pH closer to 3 than 4 have a bright red colour whilst wines with a pH close to or above 4 have an apparent colour that more closely resembles purple or even blue! (Late harvest monster Shirazes for example....).
Red or white?
What are the main differences between red and white wine? Colour, and ...? Tannins of course.
So, red grapes contain anthocyanins and tannins, whilst white grapes don't? No, the only thing that differs between red and white grapes is the lack of anthocyanins in whites, apart from varietal differences such as those between a Cabernet Sauvignon and a Shiraz grape.
Some nifty research done by Simon Robinson and coworkers at CSIRO Horticulture (Adelaide) has suggested that the the difference can be traced to the presence or absence of a single gene product, namely a cyanidin-3O-glucosyltransferase . The lack of this enzyme expression in white grapes results in anthocyanidins without the stabilizing sugars, which are unstable.., with a resultant absence of anthocyanin accumulation.
Thus, in theory, "white" grapes contain just as many tannins and/or tannin-precursors as red grapes.
The difference must lie in the different processing (romantically termed vinification or winemaking) of white vs. red grapes? Yes, and no! Not many nowdays "make" white wines by macerating crushed grapes until the end of fermentation, like we do with red grapes.
Probably, it would result in horribly bitter and astringent white wines with rather different aromatic profiles compared to wines made with more modern techniques. However, a beautiful paper by Vernon Singleton and his co-worker back in 1992, provided an alternative answer.
They added varying amounts of purified anthocyanins and purified polymeric phenols extracted from grape seeds (very vague term, since noone really knows what it consists of...) to white wine and allowed the mixture to stand for 10 days and mingle. Analyses of the composition later revealed that the simultaneous addition of anthocyanins and the poorly soluble polymeric phenols had resulted in the formation of anthocyanin-tannin complexes . Notably, the presence of anthocyanins significantly enhanced the retention of polymeric phenols in the wine. Only retained polymeric phenols end up in the bottle and notably, these polymeric anthocyanin-tannin complexes were more resistant towards sulphur bleaching.,
This was only an experiment and it is quite feasible that such tannin-anthocyanin complexes are retained to a much higher degree than uncomplexed tannins and tannin-precursors during fermentation, pressing and storage. A significant proportion of wine phenolics bind to grape proteins and yeast present during the initial stages of winemaking and Vernon suggested that such binding may differ between tannin-colour complexes and "free" tanninprecursors.
Differing degrees of solubilities - the anthocyanintannin complexes may be more soluble due to the presence of sugar-groups on the anthocyanins may also explain why anthocyanin-tannin complexes are retained to a greater degree.
This and the fact that completely different varieties are used for white winemaking, would explain why Vernon previously found white wines fermented in the presence of skins to be very white wine-like , ie. lacking in tannins..
The tinge at the edge of the glass is most often related to the pH of young wine as stated previously. This alone is also a good cue for wine style. A purple/blue-tinged wine has a higher pH than a bright red one.
This is explained by the different reversible equilibria that the different forms of free anthocyanins are involved in .
High-pH wines are often, but not always, made from late harvest, over-ripe grapes, since grapes loose malic acid as the season progresses, and the concentration of potassium increases due to a loss of water near the end of maturity.
In Australia we can just add a a couple of bags of acid to the must and correct it, but such additions, although often necessary in order to make well-balanced wines, can easily be overdone if we consider analytical results only!
Thus, the purple-edged wines are most likely big and fat, whilst the bright red ones are acid and tart? Not always, but often towards those two alternatives. At least in countries where acid additions aren't allowed!
The figure below illustrates clearly the effect of pH on the perceived colour of anthocyanins.
All solutions contain the same concentration of the same anthocyanin, namely delphinidin-3-glucoside. The only difference is the pH (and the buffer used to achieve the pH differences). The concentration is not very high and at a high concentration of anthocyanins, all solutions will appear black, except at the edge!
Older wines have more of a brick-red/yellow hue than young wines. Phenolics oxidize and this irreversible oxidation is merely a function of time and environment. Such reactions are enhanced by the presence of light, high temperature and oxygen that has migrated through the cork (which is why Stelvin-capped bottles will appear fresher for a much longer time, they don't allow as much oxygen to reach the wine!).
Winemakers who gamble with the addition of low amounts of sulphur dioxide will also suffer, for sulphur dioxide does just that, protects the wine from the effects of oxygen by binding to it with great agility and speed before it can do any harm!
Unlike wine, old references seldom age gracefully. Only the best survive, and poor access to old ones in this modern internet-dominated age will make even old classics easily forgotten.
Process Monitoring Steps
Crystal Removal A Clarification B
Remove contaminants like diatomite, particles, crystals and colloids Remove tartaric crystals
Microbial Testing of Surfaces
Brettanomyces Removal B
Wine Microbial Stabilization C
Clarification: remove particles and colloids
Prefiltration: protection of final filter for better economics
E Filling F
Final Filtration: remove wine spoilage microorganisms
Rinse Water Prefiltration: protection of final filter for better economics
Rinse Water Final Filtration: water sterile filtration for bottle rinsing
Ageing of Wine :
Aging is a fundamental process allowing the production of a wine with more rich and complex organoleptic qualities, a process depending on type of grapes and wine.
Wine, according to a technical point of view, is ready at the end of alcoholic fermentation. A wine which is still immature, rich of young and unripe qualities, however considered a wine according to every point of view.
Sugar, because of the effects of yeast, is now transformed into alcohol, aromas - because of fermentation - are now developed, so far from the ones of grape and of must. Whether according to a technical point of view the wine is now ready, the same cannot be said according to an organoleptic point of view.
Soon after fermentation, wine is in fact hazy, with many solid parts in suspension, acidity is pretty evident - a quality which is however welcome in most of white wines - and in red wines astringency of tannins is pretty aggressive.
The “cure” to all of these young qualities is represented by time which, together with proper wine making techniques, will give a more mature wine, with agreeable and pleasing organoleptic qualities. The phase between alcoholic fermentation and bottling is called aging, period during which wine develops and changes, also thanks to the fundamental role of oxygen, it becomes more stable while losing the typical young character.
Indeed, the aging of wine continues - although by means of different ways and natural phenomena - inside the bottle.
Bottle aging is in fact very important and allow the wine to get improved by ―refining‖ all the qualities found in a ready wine.
Despite aging is a fundamental phase for every type of wine, indeed its practice and duration varies according to many factors, such as the type of grape, vinification technique and type of wine.
Aging is then part of the ―natural‖ biological cycle of wine, however different for each of them, by following an evolution beginning with youth,
therefore developing towards the apex of aging that is when the wine will have its best organoleptic characteristics – and then moving to its decline, a period during which the wine goes towards its inexorable end.
Containers for Aging
The choice of the container to be used for the aging is done according to the type of wine to be made, the quality of grapes the wine making techniques. Every wine is different from any other, therefore the practice of aging will change according to the wanted result. In most of the cases, whenever it is thought about the aging of wine, the type of container commonly associated to this process is the cask, however this is not the best choice in every case. Every container has in fact proper qualities and characteristics making it suitable for the aging of specific wines and therefore unsuited for the aging of others.
It was already mentioned oxygen plays a fundamental role in the aging of wine, however this is not the only factor contributing to the development of the entire aging process. Other factors influencing aging of wine include the type of container, temperature, humidity, light, keeping practices, such as topping ups and rackings, as well as - of course specific qualities of wine. Every type of container offers advantages and disadvantages for the aging of specific wines, moreover it must be considered containers belonging to the same type are different one from another, with proper characteristics and qualities.
Of all the types of containers used for the aging of wine, only the ones made of wood play an active role, they give the wine their own organoleptic qualities and allow the participation of oxygen. All the other containers - as they do not have these two qualities - are generically defined as inert, that is made of materials having no capacity of changing the organoleptic qualities of wine, such as stainless steel and glass.
The main inert containers are represented by steel tanks, cement and fiberglass vats, demijohns bottles.
If it is true inert containers do not allow the passage of oxygen - of course provided proper keeping conditions are adopted - it should be considered they are however sensitive to temperature, a factor influencing the speed of aging. In case are used glass containers - such as demijohns - another factor should be considered as well, in fact by passing through the glass, it influences the aging and stability of color, in particular in white wines.
The case of wood containers is more complex, not only for the fact they allow the passage of oxygen through the pores, but also because they are made of organic material and therefore playing an ―active‖ role. In wood containers - casks, barrels and barriques - also happens the passage of wine, water and alcohol in particular, from the inside to the outside. As the aging in cask is strictly associated to the quantity of oxygen reaching the inside through the pores, this factor is widely determined by volume, type of wood used for the construction therefore the grain of wood and stave thickness - as well as temperature.
The smaller the volume of the cask, The quicker the aging,
wine ages quicker in barrique than in a cask
The effect of oxidation.
The aging of wine is the result of a series of phenomena occurring during a period of time and in which oxygen plays a role of primary importance.
In wood containers, oxygen reaches the wine thanks to the porosity of wood, ensuring a flow in extremely reduced quantity although continuous.
Oxygen also plays a fundamental role in the aging done in inert containers and, despite the keeping is done in order to avoid any contact with the air, the oxygen however gets in contact with the wine during the operations of racking.
The role of oxygen in the evolution of organoleptic qualities of wine also continues at the end of aging, when the wine is finally bottled. In bottles closed with corks it in fact occurs an exchange of oxygen from the outside to the inside of the bottle through the pores of the cork itself. This process is fundamental for red and white wines destined to the aging in bottle, whereas for white wines not suited for aging, the contact with oxygen causes the loss of fresh and fruity organoleptic qualities.
The phenomena taking place during the aging of wine are divided into three categories:
1. 2. 3.
chemical phenomena, physical phenomena, physical-chemical processes.
Chemical phenomena are represented by oxidation and oxyreduction, esterification, condensation and copolymerization; Physical phenomena include saturation, precipitation of solid substances, evaporation, loss of carbon dioxide.
Physical-chemical processes are mainly about flocculation and sedimentation, indispensable to get a limpid and stable wine.
These processes occurs for all the duration of aging - therefore for all the life cycle of wine - including the period of aging in bottle. The velocity and the time required for the development of these phenomena depend on many factors of physical and chemical nature occurring during aging, last but not the least, on the specific qualities of grapes and the type of vinification.
As the oxygen is the most important factor in the aging of wine, oxidation is therefore the main chemical phenomenon. The bond between wine and oxygen is very strong, not only it is indispensable for the aging , but it also gets rapidly combined to many elements contained in the wine , therefore causing oxidation. Oxygen dissolves in the wine both during the aging in wood containers as well as during the operation of rackings and bottling. Oxidation of wine is a process essentially concerning some components only, such as tartaric acid, alcohol, polyphenolic substances and coloring substances.
Tartaric acid - in pure
solution - it is not subject of any oxidation, however in presence of iron or copper occurs its oxidation and degradation.
Alcohol, because of the
bond with oxygen, get oxidized and produces acetaldehyde, also known as ethanal.
Oxidation of tartaric acid is very important for the development of the so called tertiary aromas, that is the aromas developing with aging.
More important is the oxidation of polyphenolic and coloring substances.
Oxidation of polyphenolic substances - commonly defined as tannins - is something usually happening in red wines only. . Oxidation of polyphenolic substances produces a strong diminishing of wine's harshness and its astringency. Oxidation of polyphenolic substances is very important for the improvement of organoleptic agreeability of a red wine, in particular wines produced with grapes rich in tannins . Besides oxidation, with time polyphenolic substances change as well, they aggregate and form bigger molecules, giving origin to polymers. This transformation makes the astringency less aggressive, in other words, the wine gets smoother and more pleasing.
The oxidation of coloring substances is a phenomenon occurring both in white and red wines. In white wines the color gets darker hues of golden yellow, whereas in red wines purple hues are soon replaced by ruby red, then garnet and finally brick red. In white wines the color can also change in consequence of the oxidation of alcohol, with an abundant production of acetaldehyde, causing a strong change in color with golden or amber yellow hues, sometimes developing some faults such as excessive acidity. The result of these phenomena is commonly known as maderization.
High temperatures accelerate oxidation whereas lower temperatures favor the dissolution of oxygen.
Some substances found in wine, such as polyphenols, sulfur dioxide and some acid substances, make the oxidation of some wine's components difficult: this explains the slow aging of wines produced with grapes rich in polyphenolic substances.
The esterification is another important phenomenon taking place during the aging of wine. Responsible of esterification is the reaction between alcohol and the acids found in wine and which give origin to esters, such as ethyl acetate and ethyl lactate. Only volatile esters influence the aromatic profile of wine, most of the times responsible for unpleasing aromas.
When the aging is done in wood containers, after some years it is observed a loss of alcohol caused by evaporation. The quantity of lost alcohol essentially depends on the volume of the cask and the grain of wood, however it is generally from 0.2 to 0.3% .
Some red table wines appreciate in quality, developing less astringency and colour, and a greater complexity of flavour with ageing in oak cooperages of up to 500-gallon size for two to three years. In the best red wines, additional improvement may continue with two to twenty years of bottle ageing (the rate of ageing being lower in the bottle than in the barrel). Many dessert wines improve during cask ageing, particularly sweet sherries, but extraction of excessive wood flavour must be avoided.
Those rosé and dry red wines that will not improve with long cask and bottle ageing are aged for a short period of time, clarified, and then bottled. More than 90% of all table wines are probably marketed and consumed before they are two years old.
In dry white wines, a fresher flavour is considered desirable, and the chief benefit of ageing is greater clarification as various undesirable substances are precipitated. These wines are rarely aged in the wood for long periods, and some are never kept in wood. This change is possible because of the efficiency of new clarification methods.
Earlier bottling of white wines reduces cost for storage and handling in wooden cooperages, and produces fresher, fruitier flavours. Sweet white table wines benefit by some ageing in wood.
Bottling of Wine :
Choosing Bottles and Corks:
Although this could be seen as excessive, the choice of bottles and corks is a factor representing a fundamental step in bottling. In particular the cork, as its quality and health ensure a better keeping over the time and, in particular, a lesser risk against the spoilage of wine. One of the most frequent risks is represented by the famous ―corky smell‖, caused by a chemical compound known as 2,4,6-trichloroanisole, 246-TCA in short.
According to the type of wine to be produced, we will proceed with a proper choice of corks. For red wines destined to a long time of aging in bottle, choosing a high quality natural cork is indispensable. We will choose a high quality natural cork - made of just one whole piece of cork - with a minimum length of 45 millimeters. For white wines, or however wines whose consumption is done within some months after harvesting, a good choice is represented by the so called synthetic corks, which, among the other things, never cause corky smell fault.
Another solution is represented by agglomerated corks - which can also be used for red wines of average aging - which also have the advantage of being cheaper, however having a lower quality than one-piece corks.
In any case, no matter the type of cork chosen, it is advised to use corks having a minimum length of 45 millimeters.
Also the choice of the bottle must be done carefully. Besides the considerations about traditions, that is in all those cases in which a territory identifies its wines also by the shape of the bottle, it should be noticed every bottle has its own characteristics. As for red wines destined to a long aging, and which could produce a remarkable quantity of sediments, it is indispensable to use a bottle with a pretty steep shoulder, such as the Bordelais bottle.
The shoulder of this bottle offers in fact a useful barrier at the moment of pouring, by keeping any possible sediment. Bordelais bottles can also be used for white wines, however it is best to use Burgundy or flute bottles.
The color of the glass is very important, as it offers an essential protection against the effects of light. For this reason it is best to choose bottles with dark green or brown colored glass.
Hygiene is a fundamental requirement in any phase of wine making. Although Louis Pasteur defined wine as «the most healthy and hygienic of beverages», this does not mean the hygiene in wine making is naturally present: it is a specific condition provided by the producer. Particular care must be paid on the hygiene of bottles, as they could easily spoil the wine. Before proceeding with the bottling, it should be began by cleaning bottles.
In home wine making can certainly be used recycled old wine bottles, provided they are scrupulously cleaned. Recycling wine bottles, besides representing a good operation of material recycling, also allows a remarkable saving of money because it avoids the purchase of new ones. The same cannot evidently be said for corks, because as soon as they are used, they cannot be reused also because - and in particular - of the hole produced by the corkscrew during the uncorking of the bottle.
The cleaning of bottles can be done by using specific products available at specialized wine making shops, or by using a solution made of water and potassium metabisulfite, therefore allowing the bottle to completely drain. The same solution will be used for ; cleaning pipes, siphons, carafes and any other tool used for the bottling of wine.
For cleaning the bottles - an operation which should be done also on new bottles - it is enough to dissolve 3-4 tea spoons of potassium metabisulfite for every liter of water. With this solution will be carefully rinsed all the bottles and all the tools used for bottling. Also the corker must be clean, at least the parts which will be in contact with the neck of bottles. Before beginning bottling operations and bottle filling, it will also be useful a final organoleptic test on wine, in order to make sure about its quality after the racking.
Racked wine and clean bottles: now everything is ready and it can be proceed with the operation of bottling. Before proceeding, we also have to make sure we have everything at hand, in particular the corker and corks.
The operation of bottling can be done by using a siphon with which we will transfer the wine from the keeping container to bottles, or - for small quantities – by using a carafe.
In specialized wine making shops are also available many types of siphons to be used for bottling: from simple pipes to siphons with manual taps to interrupt the flowing of wine, as well as with automatic devices which can regulate the level of wine in every bottle. All of these solutions are very cheap, therefore it is better to purchase a siphon with an automatic leveling device, in order to ensure the same quantity of wine - as well as the same quantity of air - in every bottle.
The quantity of air left between the wine and cork represents a very important factor in bottling.
As it is commonly known, oxygen - when present in remarkable quantities - is considered as an enemy of wine, as it causes unhealthy oxidations with the consequent spoilage both of stability and and organoleptic qualities of wine. In leaving the proper space of air, it should also be considered the length of the cork in order not to excessively fill bottles. However, it is always suggested the distance between the wine and the cork not to be longer than one centimeter.
It should also be remembered in wines allowed to age in bottle for a long time - usually many years - the level could also diminish, therefore in filling the bottles we should also consider this aspect.
After having filled the bottles to the proper level, we will proceed with corking and, if wished, to put a capsule to the bottle.
Capsules are available at specialized wine making shops and ensure a higher hygiene both of the bottle's neck and cork.
After having bottled the wine and corked the bottles, it is now the time of storing and keeping bottles. Before transferring the bottles to the keeping room, it is a good practice to put labels in order to keep track of our wine and have a better information about the content. Labels can be created according to the taste and fantasy of the producer,however it is suggested to at least write some essential information, including the name of the wine type, vintage and, if possible, the grapes used to make it as well as their relative percentages.
Other useful information are the date of bottling and the number of bottles obtained in that occasion. In order to ensure a better keeping of the wine, it is essential the room in which are being stored the bottle provides the right conditions for this purpose. In home wine making it is not always possible to have a room to be used as a cellar
It will be chosen a pretty dark room - even better, completely dark - sufficiently aerated in order to prevent the development of unwanted molds, with a temperature of about 15° C (59° F), possibly constant all year long, and with a humidity of 60-70%.
It is important the temperature to be as much constant as possible and never going down 15° C, as lower temperatures favor the precipitation of tartrates and sedimentation. Bottles destined to an immediate consumption - that is within few months after bottling - can also be kept in vertical position, whereas for wines destined to long period of aging, it is indispensable the bottle is kept in horizontal position.
The contact with the wine in fact ensures a better elasticity to the cork while avoiding dangerous shrinkage which could favor the entering of oxygen inside the bottle. Before consuming the wine, it is better to wait at least one month, even better, two months. This time will in fact allow the wine to refine and to stabilize even more, while favoring a better integration of the sulphur dioxide used for the racking.
Cellaring Wine :
Most people assume that the longer that you keep a wine, the better it will get since its best to store wine under certain conditions, like in a cool damp underground cellar, this is known as "cellaring" wine. It is a misconception that you MUST age wine. The fact is, throughout the world, most wine is drunk "young" (that is relatively soon after it is produced, perhaps 12 to 18 months), even wines that are "better" if aged. While some wines will "mature" and become better over time, others will not and should be drunk immediately, or within a few years.
Tannin is a substance that comes from the seeds, stems and skins of grapes. Additional tannin can come from the wood during barrel aging in the winery.
It is a preservative and is important to the long term maturing of wine.
Through time, tannin (which has a bitter flavor) will precipitate out of the wine (becoming sediment in the bottle) and the complexity of the wine's flavor from fruit, acid and all the myriad other substances that make up the wine's character will come into greater balance.
Generally, it is red wines that are the ones that CAN (but do not have to be) produced with a fair amount of tannin with an eye towards long term storing and maturation. The bad news is that you shouldn't drink it young since it will taste too harsh (and probably cost too much, besides). The good news is that after a number of years, what you get is a prized, complex and balanced wine.
!!!Remember that red wines get their color from
the stems and skins of the grape. This gives the wine tannin and aging capacity. White wines may have no contact with the stems and skins and will have little tannin (though some can be added, again, through barrel aging). Therefore most white wines don't age well. Even the ones which do get better through time will not last nearly as long as their red cousins. A fair average for many "ageable" whites would be about 5 to 7 years (some might go 10). On the other hand, really "ageable" reds can easily be kept for 30 years and longer.
Storing Wine :
For wines that should be aged, a cellar should have proper: Temperature which does not have rapid fluctuation. 55 degrees Fahrenheit is a good, but you can live with 50 to 57 degrees Fahrenheit (10 to 14 degrees Centigrade).
Wide swings intemperature will harm the wine. Having too high a temperature will age the wine faster so it won't get as complex as it might have.
Having toolow a temperature will slow the wine's maturation.
Humidity about 60 percent is right.
This helps keep the cork moist. The wine will oxidize if the air (and its oxygen) gets to it. If the cork dries out, it can shrink and let air in. This is another reason to keep the bottles on their sides. The wine itself will help keep the cork moist. Lack of light. Lack of vibration. Lack of strong odors. Whatever it is that is causing the odor stands a good chance of getting through the cork and into the wine.
Special Wines :
The procedures discussed above are primarily concerned with the production of still (nonsparkling) table wines. Sparkling, dessert, and flavoured wines require special techniques.
Sparkling Wines :
Wines containing excess carbon dioxide are called sparkling wines. They are always table wines, usually containing less than 4% sugar. They can be produced using two basic techniques, namely via a second sugar fermentation, often induced artificially, or direct carbonation, involving the addition of carbon dioxide.
Sparkling wines result when the escape of carbon dioxide from the fermenting liquid is prevented. The basic material is usually a dry white, rosé, or red table wine. Sufficient sugar is added to the basic wine to produce a pressure of about five or six atmospheres (units of pressure, each equal to 760 millimetres of mercury) following fermentation, assuming there is no loss of carbon dioxide.
The size of the fermentation container may vary from 0.1 to 25,000 gallons. Bottles or tanks used for this type of fermentation must be capable of withstanding pressures as high as 10 atmospheres.
Use of tanks equipped with pressure gauges allows excess pressure to be let off as needed. The special bottles used for sparkling wines are thicker than normal in order to withstand pressures in the range of seven to nine atmospheres. The neck of the bottle is shaped either for seating a crown cap or with a lip that catches a steel clamp to hold the cork in place.
The basic wine is clarified before being placed in the fermentation container.
Several wines are usually blended to secure a base wine of the proper composition and flavour balance. The original alcohol content should be only 10-11.5%; the secondary fermentation will result in an increase of about 1%. The pH should be 3.3 or slightly less, with 0.7% or more total acidity calculated as tartaric acid, and the wine should have a fresh fruity flavour. No single or pronounced varietal character should predominate in the base wine, except in muscatflavoured sparkling wines. Special care is necessary to avoid wines with any off character in odour or taste, or any trace of undesirable bacterial activity.
The clarified wine is placed in the fermentation vessel, and the requisite sugar for the fermentation, about 2.5%, is added, along with 1 to 2% of an actively growing yeast culture. The strain of yeast selected should ferment adequately in wines of 10 to 11.5% alcohol as well as under conditions of high pressure. The yeast cells should settle (agglutinate) rapidly and completely after fermentation.
The secondary fermentation is carried out at 10 to 12°C for best absorption of the carbon dioxide produced and should be completed in four to eight weeks.
To save time, both tank and bottle fermentations are often conducted at temperatures of 15 to 17°C or even higher, and the secondary fermentation is frequently completed in 10 days to two weeks.
Tank Fermentation Additional differences between tank- and bottle-fermented wines may develop after secondary fermentation. Upon completion of fermentation, tank-fermented wines are filtered to remove the yeast deposit and then bottled.
The filtration operation can introduce air, sometimes leading to oxidative changes affecting colour and taste. In addition, it is difficult to accomplish the necessary filtration, removing any viable yeast cells, without reducing the level of the pressure that has been built up within the wine. Because of such difficulties, sulphur dioxide may be added to tank-fermented wines in order to prevent refermentation. While still in the tank, the wine is sweetened to the desired level by the addition of inert sugar syrup.
Bottle-fermented wines may also be clarified soon after fermentation. In the transfer process, the bottle-fermented wine is transferred, under pressure, to a second tank, from which it is filtered and bottled.
In this case, as with tank-fermented wines, little ageing of the wine takes place in contact with the yeast, and sulphur dioxide may be added. The transfer process is widely used in the United States, Germany, and elsewhere.
In contrast, in classic bottle fermentation, or méthode champenoise ("champagne method"), the wine remains in the bottle, in contact with the yeast, for one to three years. During this period of ageing under pressure, a series of complex reactions occur, involving compounds from autolysed yeast and from the wine, resulting in a special flavour. Bottle-aged wine is rarely transferred, filtered, or rebottled because the addition of sulphur dioxide, required to prevent oxidation, would interfere with the delicate aroma so carefully developed by ageing. Aged bottle-fermented wines therefore are usually clarified in the bottle. In this process the bottles are placed neck down in special racks at a 45° angle.
Each day the bottle is turned to the right and left, inducing the yeast debris within to move down the side of the bottle onto the cork. This process, riddling or remuage, may last from a few weeks to several months. When it is complete, all of the yeast is on the cork, and the bottle is gradually brought to an inverted position of 180°. Mechanical remuage in large containers is widely practiced.
In the traditional procedure, the cork is slowly pulled out, and the pressure within the bottle propels the sediment out of the bottle. In the modern procedure, to prevent undue pressure loss, the bottle temperature is lowered to 10 to 15°C. The neck of the bottle is placed in a freezing solution and frozen solid.
When the crown cap, or cork, is removed and the yeast deposit is ejected, the process is called disgorging, or dégorgement.
The bottle is quickly turned to an upright position. When performed properly, disgorging (which is usually mechanised), involves the loss of only 3 to 5% of the wine. The bottle is held under pressure while it is refilled.
The filling solution is a small amount of sweetening dosage, usually white wine containing 50% sugar. The amount added depends on the degree of sweetness the producer desires.
Wines labelled brut, or sometimes nature (a term also applied to a still champagne), are extremely dry (very low in sugar content), usually containing 0 to 1.5% sugar; Wines labelled extra dry or extra sec, or dry or sec, are sweeter, often containing 2 to 4% sugar; semi-dry or demi-sec wines may contain 5% or more sugar; and sweet or doux wines have about 8% sugar.
In commercial practice, there is considerable variation in the exact degree of sweetness described by a specific term. If the dosage does not bring the contents to the desired level, more wine of a previously disgorged bottle is added. The closure, made of cork or plastic, is held in place with a wire netting.
If the wine has been aged for two or three years, the sugar in the final dosage does not ferment, as that in the original dosage did, because few viable yeast cells remain. Even in wines aged for shorter periods, skilful disgorging leaves few viable yeast cells on the sides of the neck of the bottle.
Furthermore, the wine lacks oxygen to stimulate yeast growth and is lower in growth-promoting nitrogenous constituents and higher in alcohol than the original wine. The high carbon dioxide content also has a repressive effect on yeast growth.
When bottle-fermented wines are fermented very rapidly and disgorged early, however, it is customary to add some sulphur dioxide with the final dosage to repress yeast growth.
In the United States, tank-fermented wines must be labelled "fermented in bulk" or "bulkfermented". Bottle-fermented wines may be labelled "bottlefermented", but only wines handled by the classic method may be labelled "fermented in this bottle―.
Carbonation is a less demanding process but is used infrequently. Carbonated wines have many characteristics of fermented sparkling wines, and this simple physical process is much less expensive. The action of the second fermentation under pressure may produce especially desirable flavour byproducts, however, and there is greater prestige value attached to fermented sparkling wines. In some cases, the wines used as a base for the carbonated sparkling wines may be overmature or otherwise inferior to those used for the fermented sparkling wines.
The base wine used for carbonation, like the base wine for fermented sparkling wines, must be well balanced, with no single varietal flavour predominating. Young fruity wines are preferred, and the wine should not contain any trace of off-odours. Since no secondary fermentation takes place, wines of 11.5 to 12.5% alcohol are used.
The wine should be tartarate-stable, metal-stable, and brilliant, and the sulphur-dioxide content should be low. For white wines, the colour should be a light yellow.
A variety of techniques have been used for carbonation. Production of carbonation by passing the wine from one bottle to another, under carbon dioxide pressure, is now seldom employed because of its slowness. Carbonation has been produced in bottles after deaeration, and this technique could be adapted to multibottle operations.
Direct carbonation is frequently practiced with cold wine in pressure tanks, and if the stream of gas is finely divided, good carbonation is obtained. Pinpoint carbonation, spraying the wine into a pressure chamber containing carbon dioxide, may also be employed.
Following the carbonation procedure, the wine is bottled under pressure. A cork or plastic or crown cap closure is applied, the label is affixed, and the wine is cased for distribution.
In many countries, there is a higher tax on fermentationproduced sparkling wines than on carbonated sparkling wines. **The two types also have different labelling requirements, and the process of carbonation usually must be stated on the label. There are a few low-level carbon dioxide wines on the market, produced either by fermentation or by carbonation.
There are a few wines in which the carbon dioxide comes not from alcoholic fermentation, but from malolactic fermentation of excess malic acid in the wine. The vinhos verdes wines of northern Portugal are examples of this type. This fermentation is sometimes responsible for undesirable gassiness in red wines.
Typical shapes of glasses used for sparkling wine
The addition of alcohol during or after alcoholic fermentation produces fortified wines of over 14% alcohol, generally called dessert wines in the United States. In most countries, these wines are taxed at higher rates than those of 14% alcohol or lower.
Fortification has two purposes:
(1) to raise the alcohol content sufficiently (usually between 17% and 21%) to prevent fermentation of all of the sugar and (2) to produce types with a special alcohol character. The alcohol used for fortification is usually (legally required in most countries) distilled from wine.
The distillation of the fortifying spirits is carried out to ensure a high amount of alcohol, usually 95 to 96%. Industrial alcohol has also been employed in a few countries . The repressive effect of alcohol on alcoholic fermentation increases rapidly as the alcohol content is raised above 14%, particularly in the presence of sugar. To secure prompt cessation of fermentation, the added alcohol must be rapidly and uniformly mixed with the fermenting must; this is accomplished by stirring or mixing with compressed air.
In the simplest type of fortification, the initial fermentation is allowed to proceed nearly to, or all the way to completion. The resulting wine is usually subjected to a baking process, as in Madeiras and California sherries, lasting for one to four months, at 58 to 65°C. If the wine is low in sugar content, heating will change its flavour and colour only slightly; with greater sugar content, a more caramelised flavour, typical of sweet Madeiras and sweet California sherries, is produced.
When white must is fortified during fermentation, the resulting wine is sweet, the degree of sweetness depending on the original sugar content of the must and the time of fortification. Some types, fortified early, produce very sweet wines. Muscatels, produced in many countries, are often of this type.
Red sweet wines , such as port , are more difficult to produce . Although the grapes must be fermented with the skins to extract colour , the fermentation cannot be continued for long if the requisite sugar is to remain in the finished wine. One method of securing sufficient colour is to use grape varieties containing large amounts of pigments in their skins. The skins and juice are sometimes heated to about 65°C to extract colour.
The flor sherries, such as the dry or fino-type sherry produced in Spain , are a special type of dessert wine. The base wine is fortified to about 15% alcohol, and a special alcohol-tolerant film yeast develops as a film on the wine surface. Acetaldehyde, an aldehyde, is one of the flavour products produced by this procedure.
Following this process, the alcohol content may be further raised to 16-18%. By adjusting the oxygen content, the flor yeast may be induced to develop and produce acetaldehyde in a submerged culture, a process used commercially in California.
Marsala, a type of dessert wine produced in Sicily, has a dark amber colour and burnt sugar flavour, derived from the addition of grape juice that has been cooked and reduced to about onethird its original volume.
Dessert wines aged for only short periods lack the complex flavour of those dessert wines aged in small oak cooperages for at least two to four years. During ageing, white wines gradually darken in colour, while red wines become less red and more amber.
Flavour becomes more complex and mellow as wood flavour is extracted from the container, various substances in the wine become oxidised, and complex compounds of acids and alcohol are formed.
If the wood containers are stored in warm, dry rooms, more water than alcohol is lost, and the alcohol content of the wine increases. This effect is common in dessert wines from the south of Spain. At lower storage temperatures and normal humidity, there is little change and sometimes even a slight decrease in alcohol content.
In the production of certain wines, special character is achieved by blending wines of different ages, a technique often used for port blends. By varying the proportion of the various wines, a range of types varying in colour and flavour may be produced. The blending may be performed continuously, as in the solera system common in Spain. This process involves a series of casks graduated according to the age of the wine each contains.
One or more times each year, a portion of wine, usually 10 to 25%, is taken out of the oldest cask. This is replenished from the next oldest containers, and these in turn from younger containers.
After a number of years, depending on the portion withdrawn each year and the number of years since the start, the average age of wine in the oldest container no longer changes. This process is called a fractional-blending system.
Fruit wines, derived from fruits other than grapes, include cider, made from apples; perry, produced from pears; plum wine and cherry wine, and wines made from various berries. They are frequently made by home winemakers and have some commercial importance in cold climates where wine grapes are not produced.
Cider and perry are important products in England and the northern parts of France; fortified cherry and blackcurrant wines are produced in Denmark.
Important American fruit wines, produced mainly on the eastern coast, include apple, cherry, blackberry, elderberry, and loganberry wines. Various kinds of fruit wines are exported from The Netherlands, Denmark, Poland, Bulgaria, Hungary, Serbia, and Israel.
Fruit wines usually have sweet flavours and should retain much of the flavour and colour of the original fruit.
The musts are high in acid content and require dilution with water and the addition of sugar before fermentation. Many commercial fruit wines contain about 12% alcohol. When they are fortified with brandy, derived from the same fruit, the alcohol content is about 20%. Cider and perry usually contain between 2% and 8% alcohol.
Vermouth, a flavoured wine product, probably originated in Turin in the 18th century as a sweet dessert wine with various Mediterranean and other herbs and plant materials added.
A similar product, lower in sugar content, was produced in the south of France. Although sweet vermouth is often considered an Italian type and dry vermouth usually refers to the French type, these two countries now produce both types.
Various producers have their own formulae, and the herbs and spices used as flavourings include bitter orange peel, cinnamon, clove, coriander, mace, marjoram, nutmeg, saffron, and wormwood. Aperitif wines, usually taken before meals, are made by adding quinine and other ingredients to sweet, heavy wines. In France they are marketed under such brand names as Byrrh, Dubonnet, Lillet, and Saint Raphaël; in Italy they include Campari and Punt e Mes. Wine coolers, popular in the United States, are wines of low alcohol flavoured with fruit juices.
There are various flavoured wine beverages, frequently mixed by the consumer and sometimes bottled by a manufacturer, in which flavouring materials are added after the manufacture of the wine. May wine, of German origin, is a type of punch made with Rhine wine or other light, dry, white wines, flavoured with the herb woodruff and served chilled and garnished with strawberries or other fruit.
Sangria, a popular punch in many Spanish-speaking countries, is made with red or white wine mixed with sugar and plain or sparkling water, flavoured with citrus fruit, and served chilled.
Mulled wine is usually made with red wine diluted with water, sweetened with sugar, flavoured with such spices as cloves and cinnamon, and served hot .
Glogg, a hot punch of Swedish origin, is frequently made with red wine and contains spices, almonds, and raisins.
The Uses of Wine :
Although there are many classes of wines, they are all used under six specific classes. Theses main classes of wines include aperitif (or better known as appetizer wines), red dinner wines, white dinner wines, sparkling wines, table wine and dessert wines.
The most popular dinner wines are the red, white and sparkling wines. These wines are very popular because they are made to be drunk with food. They are also known as light wines because they only contain approximately 10-14% alcohol.
The other aperitif and dessert wines are richer and sweeter than the light wines and also contain 14-20% alcohol. These wines have been fortified to make them stronger.
Aperitif (Appetizer Wines):
These wines include Dry sherry, Madeira, vermouth and other flavored wines made to be drunk before eating a meal.
White Dinner Wines:
These wines are usually either very dry or rather sweet. White meats, seafood, and fowl go well with this extremely delicate flavor.
As recommended, the white wines should be served chilled. These wines include Rhine wines, Chablis, sauterne, and wine made from different grape varieties such as Chardonnay and White Riesling.
Red Dinner Wines:
These wines are usually dry, meaning they are without sugar. These go extremely well with main-course dishes. LCBO wine experts recommend these with red meats, spaghetti, and highly seasoned foods. For full effect, red wines should be served at a cool room temperature to bring out their aroma.
The most popular red dinner wines are claret, Burgundy, and Chianti. Some red dinner wines are named for a certain variety of grapes, such as Cabernet Sauvignon. Another classification of red wines is the rose wines. These are also better known as the pink dinner wines. They are to be served with almost any dish, but they are considered the best with cold meats, pork, and curries
These wines are totally different from other types of wine. Unlike the others, they contain bubble of carbon dioxide, as do the soft drinks. To have this effect, the wine ferments in an open container. The carbon dioxide then escapes into the air. These sparkling wines are fermented twice.
The second fermentation would take place in a second container where the carbon dioxide fermentation would take place in a second container where the carbon dioxide gases would mix with the liquids since the container is sealed. The bubbles are caught and remain in the wine. Champagne (white) and sparkling Burgundy (red) are the most common sparkling wines. These are usually served at any meal with any course. These are most frequently served at banquets, formal dinners and weddings.
Light wine is fermented grape juice whose alcohol content falls within a certain range defined by law. Furthermore, table wine is not bubbly. (Although some table wines have a very slight carbonation, the amount is not enough to disqualify them as table wines.) According to US standards of identity, table wines may have an alcohol content that is no higher than 14 percent. In Europe, light wine must be within 8.5 percent and 14 percent alcohol by volume. So unless a wine has more than 14 percent alcohol, which usually means that extra alcohol has been added, or it has bubbles, it is a table wine or a light wine.
These wines are only classified under Dessert wines because they are sometimes served with desserts. Among these wines are port, sweet sherry, Tokay, and muscatel. They range from medium-sweet to sweet.
Serving Temperatures for Wine:
More wine is ruined by being too warm than too cold. A wine that is served too cold is easily warmed, but a wine served too warm can be difficult to chill. Therefore, when in doubt, serve it colder than you might think necessary. A wine that is too warm tastes alcoholic and is not a pleasure to drink.
In general, white wines are served cooler than red wines.
These serving temperatures should be used as guidelines. 65°F / 18°C would be the equivalent of leaving the wine out at room temperature for about 4 hours. 39°F / 4°C can be achieved by leaving the bottle in the refrigerator for about 4 hours.
65°F / 18°C Australian Shiraz, California Cabernet Sauvignon, Rhône Wines, Vintage Port
63° / 17°C Bordeaux, Châeauneuf-du-Pape, Ribera delDuero, South African Pinotage and Catalonian, Chilean, and Australian Cabernet
61°F / 16°C Red Côte d'Or Burgandy, southern French Reds, southern Italian reds, Rioja, Toro, Australian and California Pinot Noir, Tawny and Ruby Ports
50°F / 15°C Côte Chalonnaise, Douro red table wines, young Zinfandel, Oregon Pinot Noir, New Zealand Cabernet and Pinot Noir, Oloroso and Cream sherries, Bual and malmsey Maderias.
57°F / 14°C Chinon, Bourgueil, northern Italian and Washington State Cabernet Sauvignon, Valpolicella, young Chianti
54° – 55°F / 12 – 13°C Young Beaujolais, red Sancerre, Bardolino, Lago di Caldaro, young Sanish and Portuguese reds, vin de pays
50°F / 10°C California and Australian Chardonnay, Sauternes, top white Côte d'Or Burgundy, sweet German Wines, Rhine and Mosel Kabinett and Spätlese, Tokay, Australian liqueur Muscat, Italian oaked Chardonnay, oaked white Rioja, Fino and Amontillado Sherries, sercial Maderia, white Port.
48°F / 9°C Good white Pessac-Léognan and Graves, north eastern Italian whites, Washington State Chardonnay , Chilean Chardonnay, Australian Semillon, New Zealand Chardonnay
48°F / 9°C Good white Pessac-Léognan and Graves, north-eastern Italian whites, Washington State Chardonnay, Chilean Chardonnay, Australian Semillon, New Zealand Chardonnay
46°F / 8°C Alsace, Chablis, Côte Chalonnaise and mâconnais whites, dry German wines, Franken wines, Austrian Riesling, English wines, Australian Reisling, Cabernet and grenache rosé
45°F / 7°C Good Champagne and Sparkling wine, Sancere, new York State, Chilean and New Zealand Sauvignon Blanc
43°F / 6°C
White Bordeaux, Muscadet, Anjou, other Sauvignons, Asti, unoaked white Roja
41°F / 5°C
Qba German wines, Soave, young Spanish and Portuguese whites, Vinho Verde, Swiss Chasselas, Austrian Grüner Veltliner, cheap rosé
36° – 39°F / 2 – 4°C
Cheap sparkling wines
Health and Wine :
In the modern world, wine is accepted as a healthful drink. Only in the United States are we once again, beginning to rediscover its value to society. For many years, we focused in the dangers of overindulgence. To be sure, there are dangers to the over-use of wine.
Until the 18th century, wine played a central role in medicine. Wine inhibits the growth of all micro-organisms that are the cause of disease in man. Because of its alcohol and acid content, they simple die in it.