What to Do with Shea Nuts (Karité, Nku, Bambuk)

Processing

The Green pulp exterior is removed. One method is to bury the fruit in the ground so that the pulp ferments and falls off. This takes 12 days or more. The nuts are parboiled or sun dried and then smoked for 3 to 4 days. The dried nuts can then be stored for long periods without significant losses. Decortication is done by crushing the outer shell to remove kernels. Shea nuts are mainly exported as smoked kernels. The kernels will be further dried before any additional processing is carried out.

Shea nut butter

Traditionally wet processing by hand is a slow and laborious process that uses large quantities of wood for roasting. The kernels are roasted in a pot over a fire to approximately 100°C and then pounded in a mortar to produce a course paste. This is then ground between two stones to produce a smooth paste. The paste and water are mixed in a pot where the butter rises to the top. The butter can then be removed and washed repeatedly with warm water until clean. The remaining water is remove by heating. Impurities settle out and the butter can be left to cool and solidify. With the traditional technique, the fat obtained is between 25 and 40% of the dry kernel weight.

The introduction of equipment can improve upon traditional methods of production by reducing the effort and time involved and by increasing the yield. Instead of pounding by hand a mill can be used, Oil can be extracted using a mechanical or hydraulic press. Manually turned roasters can be used rather than a traditional pot. A very important consideration is the minimum throughput required to run the equipment profitably, including the initial cost, management of the equipment and maintenance.

Shea butter press

The fat is squeezed out of the heated shea-powder under high pressure. For a high amount of fat, a press capable of at 125bar pressure is required. The fat must then be cleared of all residues by bringing it to the boil together with okra, lemon juice and water. To increase the output, the process can be repeated. The resulting press cake is excellent for use as fuel for ovens and reduces the fuelwood demand. The amount of fat derived is determined by the condition of the shea nut. The yield will be greater if the harvest carefully stored and preserved. Complete inactivation of enzymes will prevent the formation of free fat acids. The heating of the powder to between 100° and 120° Centigrade is not difficult but the unassisted use of the press needs longer to learn. In order to get a maximum pressure of 125 bar a lot of force is required by the user.

Food

Used as baking fat and to substitute cocoa butter to make chocolate and other products.

Cosmetics

Shea butter is used as a base for cosmetics, skincare products moisturising cream anti ageing treatments. It also has anti inflammation properties.

Soapmaking from Shea

The cake left after the second pressing can be burned to produce potash for soapmaking or for fertiliser.

References and further reading

• Soapmaking, Practical Action Technical Brief

• Oil Extraction, Practical Action Technical Brief

• Shea Butter Extraction in Mali, Appropriate Technology Bulletin No 6, Appropriate Technology International, 1985

• Oil Extraction, Food Cycle Source Book 1, UNIFEM and IT Publications, 1987

• Appropriate technology for shea-butter production: A women’s technology in Mali GTZ/GATE

• Appropriate Technology Products of Ghana, DAPIT Project Secretariat, Ministry of Environmental, Science & Technology, 1995, ISBN 9988-7615-0-3

• Minor Oil Crops, Intermediate Technology Consultants, 1991

Useful contacts

Raise
Website:http://www.raise.org/natural/shea/shea.stm

GRATIS (Ghana Regional Appropriate Technology Industrial Service)
P.O. Box 151, Tema, Ghana
Tel: 010 233 221 4243, Fax: 010 233 221 6251

COVOL (The Cooperative Office for Voluntary Organizations)
4680 Portola Drive, Santa Cruz CA 95062, USA
Tel: 831 462.2182
Web site: http://www.covol.org/shea.html
COVOL have a shea project working primarily with women's farming groups across northern Uganda

International Centre for Underutilised Crops
Institute of Irrigation and Development Studies
University of Southampton
Southampton SO17 1BJ
United Kingdom
Telephone: +44 (0)2380 594229
Fax: +44 (0)2380 677519
E-mail:
Website: http://www.soton.ac.uk/~icuc/

Post Harvest Programme
NR International
PO Box 258
Chatham Maritime
Kent ME4 4PU, UK

CEPAZE (Centre d'Exchages et Promotion des Artisans en Zons a Equiper)
18 rue de Varenne
75007 Paris
France
CEPACE began developing equipment for shea butter production in 1980

DFID Crop Post-harvest Programme, Improved processing of Shea nuts in northern Ghana (R6631). A bridge type screw press was developed for the extraction of shea butter, local construction of the press was carried out by the Intermediate Technology Transfer Unit in Tamale

KIT - Royal Tropical Institute (Koninklijk Instituut voor de Tropen)
Postbus 95001
1090 HA Amsterdam
The Netherlands
Tel: +31 (0)20 568 8711
Fax: +31 (0)20 6684 579
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Web site: http://www.kit.nl/

Equipment suppliers

Note: This is a selective list of suppliers and does not imply endorsement by howtopedia.

Farmers' Technical Service and Technological Training Centre
P. O. Box 9899, Accra, Ghana
Manufacture batch toasters, a vertical Hand Press and motorised oil expellers.

S.I.S Engineering Ltd.
P.O. Box 45
U.S.T Kumasi
Ghana
Produced a churning and washing machine and a manual screw press.

UNATA (Union for Appropriate Technology Assistance)
G. Van den Heuvelstraat 131, 3140 Ramsel, Belgium
Spindle press oil expeller

IITU (Intermediate Technology Transfer Unit) -
GRATIS
P.O. Box 951, Northern Region, Tamale, Ghana
Produce a shea nut grinder/mill
10 hp electric & 8hp diesel