Methods for Processing Shea Products
D. Post-Harvest Production
Traditionally, development of the rural shea industry in Mali has focused on
advancing laborsaving devices, while very little emphasis has been placed on
increasing the quality of shea produced at the village level. As Peace Corps
Volunteers, we have a unique opportunity to work with and educate local
producers about the importance of shea processing practices and the effects
such practices have on the quality of their shea. Increasing the quality of
their shea product will allow the villagers to expand into larger markets,
build relationships with superior buyers, and demand a higher price for this
important natural resource.
At the producer level, why is it so important to focus on the processing and
storage of shea kernels? The simple fact is that it is difficult, if not
impossible, to produce quality butter from poorly processed nuts. Kernel
processing practices have a direct effect on quality and quantity of oil
extracted. Post-harvest processing controls the moisture levels, impurities
and contamination levels, and the microorganism content of bacteria, fungal
spores, and toxins.i The other less tangible aspects of shea butter, such as
color, taste, and texture are also affected by the post-harvest processing. ii
Buyers and traders are under pressure from larger market forces to produce
high quality shea butter, and the only way to achieve this is to start their
processing with high quality shea nuts. Poorly processed shea increases the
costs of extraction for processing firms, who are forced to correct the
imperfections with additional refinement.iii
Unfortunately, failures in the past have helped shaped a widely held opinion
that Mali exports low quality shea kernels with high moisture content and
soaring levels of impurities (e.g. from charcoal, smoke, dirt, etc.). For this
reason, important buyers have been turning to other West African shea-
producing countries, like Ghana and Burkina Faso, who offer a consistently
higher quality product. Unless Malian rural producers can increase the
quality of their shea, buyers will continue to preference other regional
producers over Malian producers. However, if offered a tangible incentive
and a practical education, rural producers can and will improve the quality of
shea produced in their area.iv Volunteers can help shea producers gain
technical and management skills necessary to develop and market a higher
quality shea product. This will give the village producer negotiating power
and allow them to develop credible, long-term market relationships. When
offered a fair price, villagers will be convinced of the value of shea and will
place a new emphasis on the proper management and protection of this
important natural resource.
Knowing the importance of post-harvest processing and its effect on shea
quality, we can now discuss the stages of shea processing. Shea production
has two distinct processing phases: transforming shea fruit into dried nuts,
and then transforming these nuts into shea butter. The first phase coincides
with the start of the rainy season, usually mid-June through early July.
During this first phase, women harvest the shea fruit, and then process the
fruit into dried nuts ready for storage. In the second phase, stored nuts are
either sold raw or processed into shea butter. The second phase encompasses
the remainder of the year, or until supplies of stored nuts are depleted. Shea
butter production generally peaks during the hot season months, a time when
other agricultural work is minimal. The text below highlights the
recommended practices in bold, explaining the importance of each step.
Following the recommended practices is a list of possible regional variations
in post-harvest techniques that volunteers might observe in Mali. These
variations are not recommended and should be avoided.
Phase I: Post-Harvest Processing of Shea Nuts
1. Ripened fruit falls from the tree, and the fallen fruit is collected from
under the tree. Harvesting is often done on the way to and from the fields,
and rarely is time set aside specifically for harvesting shea. There are two
concerns when harvesting shea: first, the shea fruit that drops to the
ground is often a living seed that will begin germinating within a week.
Germinating seeds produce low quality butter. Second, if the shea seed is
left to die naturally, it is susceptible to rot and fungal infections.v
Therefore, the shea fruit must be processed following the harvest in stages
that are designed to kill the seed in a controlled and timely fashion. It is
important to begin processing the nuts (i.e. boiling and drying) within a
week of harvesting, preventing the live seeds from germinating and the
Variations: In some regions, fruit is actively picked, shaken, or knocked
from the tree. This practice should be avoided because of the high
probability of collecting unripened or germinating fruit. Such fruit produces
immature nuts with a low butter content.
dead fruit from rotting.
Figure 2: Ripened Fruit Ready for Collectionvi
2. Fruit is sorted, and those that are spoiled, insect-infested, germinating,
and black or molded are removed. The fruit should have a sweet, edible
pulp without an abundance of latex and with no evidence of germination.
Remember that quality fruit will produce quality nuts.
Variations: Many producers at the village level do not sort the fruit before
accumulating. Spoiled nuts, if harvested and accumulated with quality
nuts, will quickly spread mold and disease to the healthy fruit.
3. The shea fruit is spread flat in a dry, shady location for no more than a
week, rather than heaped or buried. This step is not required—fruit may
be de-pulped and processed immediately upon harvest. However, women
traditionally collect small amounts of shea daily and then wait until
sufficient amounts have been accumulated to begin the post-harvest
processing. Allowing the nuts to sit for many days without beginning the
processing invites a number of problems. Fruit must be processed quickly
because long periods of storage allow decomposition and invite insect
Variations: Fresh fruit is heaped in piles near the concession or buried in
pits below ground until a sufficient amount is been accumulated; the shea
sometimes sits for months. Both piling and burying the shea fruit should
be avoided because it invites infestation, mold, and rotting.
infestation and fungal infections.
4. The shea fruit is then de-pulped, a process of removing the fruit from the
surface of the nut. The fleshy fruit must be actively removed from the
nutshell; this can be done via human or animal consumption, or by
rubbing the pulp off with an abrasive substance like sand.
Variations: The fruit is allowed to decompose during the accumulation
period, and then the pulp simply rots off. This is not preferable because it
invites fungus, infect infestation, and other animals searching for food.
5. The nuts should be cleaned with pump water to remove all fruit residue.
The village producer rarely practices the stage, but the pump water will
help remove dirt and other impurities, as well as any remaining fruit.
Nuts should be brown and not a blanched white. This stage is very
important in order for the boiling process to be effective.
Variations: This step is rarely ever practiced in traditional shea
processing. The nuts are simply boiled as is, often with much of the skins
and fruit still attached. This actually boils the fruit onto the nut surface,
which leads to rot.
6. The whole, clean shea nuts are then boiled in pump water in large pots
over a fire for an hour, or until no longer sticky. Boiling should take place
no more than four days after the shea fruit was harvested. The boiling
process prevents the nuts from germinating and allows for a high oil yield.
Boiled nuts are also easier to dry. However, having exposed the nuts to
water means you must be especially careful to dry the nuts completely
before storage. Boiled nuts can lead to high peroxide levels and frequent
fungal infections (black nuts) if not dried properly.
Variations: In some areas, nuts are smoked in mud-brick ovens. Oven-
roasted nuts or smoked nuts dry the quickest, a benefit during the wet and
humid rainy season, but smoking leads to increased carcinogen levels.
Exporters are not interested in purchasing these nuts because of American
and European restrictions on carcinogen levels. Other villages will sun dry
the fresh nuts (no boiling, smoking, or roasting). Raw sun-dried fruit
makes extraction difficult, fails to kill the enzymes responsible for
germination, and can often decrease the oil yield. Additionally, this process
is extremely slow and practically impossible in the Malian rainy season.
Figure 4: Smoking Nuts in Ovens-Not Recommendedvii Figure 3: Boiling Nuts-Recommended
7. The boiled nuts are then spread out in direct sunlight for one to two
weeks. Raised wooden trays or slats are preferable to keep the nuts off the
ground. If wooden trays are unavailable, nuts can also be spread on a
Variations: Nuts are spread on the upswept ground throughout the
concession, and women are not diligent about bringing the shea in at the
threat of a rainstorm or during high humidity periods. This makes
drying the nuts impossible.
well-swept concrete or hardened mud floor in direct sunlight. Because of
the frequent, violent rains during June and July, nuts should be protected
under clear sheeting tunnels to prevent wind and rain damage, if possible.
8. The nuts are then de-husked by striking them with simple hand tools or
by gentle mortar pounding, preferably within 3 or 4 days of drying. This
leaves only the shea kernel, the inner seed of the shea fruit and the part
from which oil is extracted. It is important to de-husk the fruit as gently
as possible to preserve the integrity of the whole kernel, i.e. to avoid
cracking the kernel.
Figure 5: Cracking to De-husk Sun Dried Shea nuts in Ghanaix
9. The kernels are washed with pump water to remove the husk and residue.
Again, this step if often ignored by the village producer, but is extremely
10. The shea nut kernels are then spread out to dry in the sunlight again,
until fully dry. Shea kernels should be dried on raised trays (wood or
bamboo slats) preferably under clear-sheeted tunnels shaped and tied to
prevent wind and rain damaged. Drying nuts on open, sunlit, clean
ground is also acceptable. It is important to take care to prevent
contamination during the drying process (e.g. human or animal feces,
chemicals, fertilizers, oil, heavy metals), because the nuts will not be
Variations: Kernels are spread on the upswept ground throughout the
concession, and women are not diligent about bringing the shea in at the
threat of a rainstorm or during high humidity periods. Many villagers do
not redry the kernels after removing the husks.
washed again before storage.
Figure 6 Shea Kernels Spread Out to Dryx
11. Nuts should be sorted again and then stored in a well-ventilated,
moisture-free area like jute sacks, large straw baskets, or on raised
wooden palates. Sorting the nuts again before storage will decrease the
likelihood of infestation or rot. Traditional raised granaries often provide
an excellent, dry atmosphere for storage. Humidity and insect infestation
can be devastating for nuts. Well-dried kernels are extremely important,
as poorly dried shea invites disease, mold, germination, and insect
infestation. General rule of thumb: the drier the better.
Variations: Nuts are often stored in plastic sacks, which increase the
humidity levels and lead to spoiling. Some producers will store the nuts in
old fertilizer bags; this is very dangerous for obvious reasons. One must
also be careful to store the nuts away from wet or fresh agricultural
Figure 7: Shea Nuts Stored in Jute Sacksxi Figure 8: Stored in Granariesxii
12. The kernels are ready for long-term storage or export. Shea can also be
taken out and re-dried occasionally when humidity levels are low to
ensure that humidity levels remain as low as possible during storage.
Phase II: Shea Butter Production
1. The dried kernels are removed from storage and pounded into a coarse
powder inside a clean mortar or with small hand tools. As with every step
Variations: The kernels are left whole.
in this process, it is important to work with clean tools to prevent
Figure 9: Hand Crushing of Shea Kernelxiii
2. The kernel powder is then dry-roasted in a large metal pot over an open
fire until all moisture is evaporated. This process brings the oil more
readily to the surface to ease the grinding process. Pounding the kernels
has the effect of increasing the surface area for water, UV, metal, and
heat damage to work on. One must be careful not to char the kernels
Variations: If the kernels are not crushed before roasting, they are often
mixed with ash or sand to preventing charring and promote more even
cooking of the whole kernel. Villagers who smoked the nuts before storage
will often skip this dry-roasting step completely.
during the dry-roasting process.
Figure 10: Roasting Crushed Kernelxiv
3. The kernels are then ground into a dark brown paste. Kernels can be
hand-ground on a flat stone or milled into paste with a commercial shea-
grinding machine in the village. The machine or stone should be clean
and used exclusively for shea, so as not to introduce impurities from other
crop residues, oil, diesel, or heavy metals.
Figure 11: Grinding Shea Kernels on a Stone Quernxv Figure 12: Milling Whole Shea Kernelsxvi
4. This shea paste is transformed into butter by vigorously hand-whipping
the paste for approximately 1 – 2 hours, in a large bucket or bowl. In this
step, the fats will begin to form a white emulsion. Gradually the
emulsified fats are skimmed, washed, and removed; the remaining paste
is beaten again, becoming lighter and lighter in color. Small amounts of
warm pump water can be added to paste while beating to raise the
Variations: Some women will directly boil the paste with water until the oil
separates and rises to the surface. It is then poured off, and the remainder is
re-boiled. This leads to oil for cooking but does not promote the
emulsification process that leads to butter.
emulsified fats to the surface.
Figure 13: Traditional Extraction-Kneading With Waterxvii
5. The removed, emulsified fat is boiled in a large metal pot over an open fire
with decanting stages to separate and clarify the oil. The remaining
water evaporates; the purified oil rises to the surface and is siphoned off,
while the impurities sink to the bottom. Some women perform an
Variations: Some regions of Mali will add plant extracts to the shea paste or
oil in order to alter butter qualities, often for medicinal purposes. Shea
buyers want pure shea butter with no foreign substances.
additional filtering step by pouring the hot oil through a cloth while
Figure 14: Boiling the Shea Butter Emulsions after Extractionxviii
6. The liquid oil is poured into a clean, dry container to cool and solidify.
While cooling, the oil is often stirred to produce an even creamy texture
and prevent crystallization. The cooled butter can be packed into balls for
selling or stored in metal pots. Traditional raw, unrefined shea butter
contains no bleaches, deodorizers, or added chemicals. Proper storage of
the butter is important in land-locked Mali because of the long, over-land
transportation required to export butter over long distances.
Variations: The shea butter balls are occasionally stored wrapped in
leaves. Some women cut the solidified shea butter before storage, and then
place the sliced butter into a large container of cool water to await the
market. This humidity is not good for the shea butter, it can cause
spoiling or ruin the smell of the better.
E. Storage Issues
The quality of shea butter produced largely depends on how the kernels are
stored during the preparation process, especially after they have been de-
pulped and processed for shea butter production. Remember a few important
things about storage:
Storage of fruit: The most important thing to remember about the fruit is not
to store the fruit for long periods of time; it does not store well. Allowing the
fruit to sit for long amounts of time invites a number of problems: insects,
animal scavengers, fungus and mold, and rot. It is also important to spread
the harvested fruit in a shady area and not to accumulate the fruit in piles or
heaps. It is extremely detrimental for the fruit to be stored in wells or pits.
The harvested shea fruit should not sit for more than four days before
removing the fruit pulp and boiling the nuts.
Storage of nuts: Make sure the nuts are completely dry before storing to
prevent fungus, spoiling, and insect infestation. Store the nuts in a dry,
clean location. Raise the nuts off the ground surface with wooden flats if
possible. Do not dry the nuts in plastic sacks or sacks woven from plastic.
Plastic raises humidity levels and causes the nuts to spoil. Nuts should be
stored in jute or woven-fiber sacks. Also, be careful not to store nuts in sacks
that previous held fertilizer or other chemicals. Traditional storage huts, if
well built, could be quite effective in storing shea; large concrete storage units
are often unnecessary. If nuts are stored in traditional granary units, these
units should be raised from the ground and should have watertight roofing.
Do not store the nuts with fresh or moist agriculture products.
Storage of shea butter: Shea butter should be stored in clean, dry containers.
Traditionally shea may be wrapped in leaves; this can contaminate the pure
shea butter. Shea butter is also often formed into balls and these balls are
placed in cool water until market time. Exposing the finished shea butter to
water can damage many of the desirable qualities of shea, additionally
women have been known to place finished shea butter in water to increase its
weight and get more money from buyers: this practice is not acceptable to the
F. Equipment and Machines for Shea Processing and Storage
Gas Stoves and other Energy Alternatives: When the shea nuts are boiled,
women traditionally use the three-rock stove with firewood. This type of
stove is very inefficient, and this inefficiency translates into higher energy
costs for the producer and greater environmental damage to the surrounding
forests. There are a number of other options that PCVs can explore to lessen
excess energy consumption by shea producers. Large gas stoves that fit with
traditional metal pots are an efficient, but expensive, option. Mud brick
stoves are another options; these still require firewood but use the energy and
conserve heat much more efficiently than three-rock stoves. Most
ingeniously, shea shells/husks themselves can be processed into fuel sources.
All of these options allow the women to save money on energy costs while also
protecting their natural fuel sources.
Shea Drying Slabs: Many shea production facilities, even those in small
rural areas, require a large, flat surface on which to spread the shea nuts out
to dry. This space should be clean, level, and exposed to direct sunlight for
much of the day. A covered cement slab that still allows sunlight to strike
the nuts is preferable especially during the rainy season.
Solar Drying Tunnels: These tunnels can be used to dry a number of
agricultural products like mangoes, onions, okra, and shea. Shea nuts or
kernels are held up off the ground by wooden or bamboo slats, which allows
the shea to dry faster by
allowing for increased air
circulation. Clear plastic is
then tented over the slats and
stretched and tied around a
wooden or metal frame. The
plastic is tied to prevent wind
and water damage to the shea.
Such plastic can be obtained in
small amounts from furniture
makers and car upholstery
locations in Bamako and
regional capitals. These dryers
are excellent for protecting the shea from rain and dust, while still allowing
sunlight to strike the shea. They are one solution for the difficult problem of
drying shea nuts and kernels during the rainy season in Mali.
Another practical design for a solar nut dryer, created by Jude Théra,
Association VIGNE, Tominion, Mali:
Cracking Machines: These machines are rarely found in Mali, but equipment
does exist to crack the nuts, removing the husk that surrounds the kernel.
These machines are expensive and impractical for most village-level
Roasters and Heat dryers: These machines
are quite expensive and are rarely found in
Mali. They essentially tumble shea, like a
clothes dryer, to dry the nuts or kernels
quickly and evenly. An example of such a
machine can be seen Diola. A concern with
such machines is that they heat large
quantities of shea at one time, and many
times this amount is far too much for the
pasting machines to process, and as a
result the producer is forced to reheat the
shea that has cooled. This is a waste of time and energy resources.
Grinding Machines: These take the shea kernels and grinding them into a
crumbly consistency. This “shea crumble” is then heated and ground very
finely into a dark brown paste. This process is quick and effective, and many
villages seeking to build shea processing facilities will set up this machine
next to the pasting machine. The same affect is achieved traditionally when
the shea kernels are pounded with a mortar and pestle.
Hand Grinding Stones: This is the traditional tool used to grind the shea
kernels into a coarse brown paste. A large flat stone rests on the ground, and
the kernels are ground against the stone with a large wooden or stone rolling
Shea Grinding/Pasting Mills: Commercial grinding
machines, which run on either electricity (rare) or
on diesel fuel, can process the roasted kernel
crumble into shea paste. These machines are often
owned by individuals or organizations, which
charge a fee for the grinding service. Make sure to
factor this cost into your business plan. Another
important point on grinding machines: these
grinding mills are often all-purpose machines used
to grind all agricultural products in a village. If the
machine is not cleaned between the grinding of
different products, it can lead to contamination.
Oil press: Oil presses are rare in Mali, and are much more likely to be found
in Ghana. The oil press, as the name implies, presses shea kernels to
forcefully expel the oil from the kernel. The process is relatively expensive
and does not yield high amounts of oil. It is not recommended.
Shea Beater: This machine is a bit of a novelty item; it
works like a giant beater that whips the shea paste
until is emulsifies into solid fats. The waste and water
are drained from the bottom and the white shea fats are
removed. These machines run on diesel fuel and fees
are typically charged for each use. Unlike traditional
hand beating, the machine shea paste is beaten only
once and the amount of butter extracted is generally
lower in comparison to traditional methods. The women
will traditionally re-beat the remainder until the
maximum amount of fats have been extracted, but the
machine only performs this process once.
Filtration Pumps and other Filtration Systems: There are a number of
options for filtering the shea oil before it is poured into containers to cool and
solidify. Two major filtration options are found in Mali.
Filtration can be achieved by simply pouring
the processed oil through a cloth filter to
remove impurities. This process can be
extremely effective, but the cloth must be
clean and uncontaminated by detergents,
Filtration pumps also exist. These
machines suck the shea oil out of one
container, pass it through a series of
cloth filters and then release the
filtered shea oil into a different
container. This system is generally
powered by a hand pump and is
very effective in producing clean,
ameliorated shea butter.
Large Storage Containers: Large butter storage containers can be used by
producers at mid-sized production units, but their use in small production
facilities is unnecessary. These giant plastic tubs store large amounts of shea
butter for sale to importers who will further refine the product before
packaging it again for retail. These lined barrels can be reused and save the
producer the cost of purchasing many small retail-sized packaging
i Dr. Peter Lovett, “Shea Processing Technical Inventory and Recommended Improved
Processing Methodology,” September 2004, prepared for Pro Karité, the World Agroforestry
Centre, the Common Fund for Commodities, and the Netherlands Government.
ii Mali Shea Kernel Value Chain Case Study , microREPORT #50, United States Agency for
International Development (USAID), March 2006, Eric Derks and Frank Lusby of Action of
iv Dr. Peter Lovett, “Shea Processing Technical Inventory and Recommended Improved
Processing Methodology: Recommendations and Conclusions.”
vi Image provided by “Improving Product Quality and Market Access for Shea Butter
originating from Sub-Saharan Africa,” a slide show prepared by Prokarite Mali.
x Image provided by “Improving Product Quality and Market Access for Shea Butter
originating from Sub-Saharan Africa,” a slide show prepared by Prokarite Mali.
xi Image provided by “Shea Processing Tech Inventory and Recommended Improved
Processing Methodology,” Dr. Peter Lovett, September 2004, prepared for Pro Karité, the
World Agroforestry Centre, the Common Fund for Commodities, and the Netherlands