Introduction
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In Brazil, where they originated, cashews had the name acaju. It appears that the Tupi people even influenced their colonialists from Portugal into the close renaming of the nut. The Portuguese simply called it caju, and hence the anglo-phone world easily adopted the similar-sounding phonetics, ‘cashew.’ Its Spanish name anarcado, reflects its botanical name. Cashew nuts first appeared in Africa in the 15th century A.D. in West Africa, perhaps Nigeria, through Portuguese explorers. They reached the Eastern and south-eastern coasts of Africa in countries like Mozambique, Kenya and Tanzania in the 16th century through the Portuguese.
Indeed, cashew nuts (Anacardium occidental) are fast thriving multiple-use trees that extend across all parts of the tropics. Africa is the epicenter of the tree as three of the biggest exporters including Ivory Coast, Tanzania and Nigeria come from the West and East African coasts. In description, the tree features an extraordinary fruit that houses a hanging inverted C nut while the succulent apple towers above it. When the hard shell is split, the flesh is a sumptuous white, smooth and nutritious snack.
The appearance of the fruit bearing the nut has elicited its description as a false fruit (pseudocarp). In Africa and elsewhere, it matures green but changes into a catchy red-yellow color that measures up to 11 centimeters in length. This apple part is full of juice and is a source of tropical drinks. In Central America, the fruit has the name mara while in Tanzania it is bibo. The actual fruit however, is the hard nut or cashew nut at the end with its curved shape.The tree itself can reach a height of 20 meters.
A single cashew nut is a leeway to health as these few nutritional details show:
•At 49 milligrams, the large apple has as much Vitamin C as citrus fruits though the nut has 0% Vitamin C value.
•At 10 milligrams, the teeth enamel and bone-supplanting calcium in the apple is also higher than that of even an avocado. The nut has 4% of the daily value of calcium.
•At 2 to 6.7 milligrams, iron is also in higher content in a cashew and its apple than other tropical fruits like bananas.This represents 37% of the daily needs.
•Potassium is quite high at 49 milligrams, to enhance the electrolyte part of blood for normal circulation.
•At 43.8 grams, the largest nutritional content of the nut other than starch is its fat, most of it unsaturated and healthier than other fruit sources. It supplies 67% of the daily needs of fat.
•The only caution is the nut oil which is a product of the shell. It is acidic and irritant to the body. It is nevertheless a recognized additive in paints, solvents and wood finishings.
The nuts come to us after undergoing heat processing in ovens. Hammer wielders then smash the tough outer shell so as to extract the simmering brown roast of a nut inside. Though they have natural salts of their own, cashew nuts need salting to taste really extraordinary. This is done after the shell-cracking takes place. More details on processing and roasting of cashew nuts are available in the Processing and Marketing section.
Cultivation in Africa
The cashew nut tree thrives well south of 25° N and north of 25°S latitudes which encapsulates all of Subsaharan-Africa. It grows for between two-and-a-half and four years before it can produce its first fruits. Fruition lasts for two decades before it reaches its peak at 30 years of age. The tree continues to produce for up to 60 years of age.
The lowlands of Tanzania, Mozambique, Nigeria, Kenya, Ivory Coast, Ghana and other countries with elevations of 0 to 500 meters above sea level are optimal for cashew nut cultivation. These altitudes meet the annual precipitation of 1000 millimeters, the plants’ requirements. For advanced-age trees, as low as 500mm annual precipitation is enough in countries like Mozambique due to humidity. The best growing lands, however provide between 1500 and 2000 millimeters of annual rainfall. The plant is hardy and its extensive roots can source for water in drought-stricken areas.
The best soil for the growth of cashew nuts is of any type as long as it is deep and of good drainage. The root system of the trees are adept at finding water and mineral sources deep in the underground. Thus, they thrive in sandy, silty soils of coastal environments well. The optimal soils are however fertile, loamy but with hints of sand. Though the plants do well under infertile grounds, they do not tolerate coral reef ecosystems at the coast.
The growing calendar of cashew nuts in Africa has different seasons. For example in Kenya, farmers grow them expecting yearly harvests in November and December while in Nigeria, the four-year old tree produces fruits yearly between January and April. With this in mind, the following is a guide on growth parameters that apply universally.
1. Cashews grow from nut seeds. In Kenya, the Kenya Agricultural Research Institute (KARI) in Mombasa offers certified seeds. To prepare the seeds, farmers dip them in ocean water with at least 100 grams of salinity for every 5-liter hydration. You can then select to plant the seeds that sink and discard the ones that float.
2. The seeds then undergo sun-drying for about 21 days to keep off rot.
3. The cashews grow well in deep holes of about 40 centimeters deep and 30 centimeters square in width. A mixture of topsoil and subterranean soil with a bucket of decomposed manure per hole is ideal.
4. The best spacing criteria is 12 by 6 meters. This will provide approximately 140 healthy plants in every hectare. Dry areas need wider spacing of 12 meters squared per tree to reduce resource competition.
5. There are two means of planting: the harder of the two but permanent is that of directly planting the seeds in the holes. The conventional means of planting is that of using three seeds for every hole. The other method is that of using raised nurseries in polythene bags. Though this method requires transplanting, is easy and works in drought-stricken areas. In half a month or a whole month at most, the seeds will have germinated.
6. In terms of tendering, the plants grow well with other crops like beans which also tolerate dry conditions. Exceptions include sweet potatoes which contribute to insects that affect the crop. During the initial 24 months of the plants’ growth, the whole area under the tree branches should be without any vegetation to reduce resource pressure for the young tree.
7. The trees are also tendered by frequent pruning at intervals of three to four months. For each pruning period, farmers should leave one healthy cashew tree unpruned. Pruning is a tasking task that requires propping the tender tree first, then slashing off offshoots that are up to approximately 1 meter off the ground.
8. Pests to be on the look out for include Helopeltis bugs. These slight crawlers measure up to 10 millimeters in length and possess notable antennae that is double the body length. These borers eat leaf, vein and stems’ tender areas which may lead to their falling off. Some plants like cotton and some tubers like sweet potatoes are agents of the bugs and are therefore not ideal intercrops. Organic control means include attracting predators like ants which destroy the bugs without wrecking havoc on the nut trees. Coconut bugs are lesser threats but have similar bodily characteristic as Helopeltis including lengthy antennae. They attack fruits which can have consequences on the diminished quality of the shell-enclosed kernels.
9. The first fruits on a cashew nut in countries like Mozambique come early at 3 years of age. In most other places the first fruits appear at 4 years of age. This is before the tree matures at nine or ten years of age after which it grows no taller. It can thereafter stay for thirty to forty years in useful harvesting.
10. Harvesting involves the basic picking of fallen nuts and easing off the succulent apple from the hard cashew nuts. When picking is done daily during the rainy season or each seven days in the hot period, the harvest for a full tree will be over in three to six months. Each tree produces 6 kilos which can go up to double that yield in the best season.
Processing and Marketing Cashew Nuts
After each harvest, Africa’s cashew nuts go into two grades. The bulk constituting three-quarters of the yield is Fair Average Quality (FAQ). It is the best grade which contains the perfect nuts in neutral or bright hue and uniform shell. The second is Under Grade (UG), which is around a quarter of the total yields. The grade constitutes seeds with blackened shells but still in good shape.
For processing purposes, cashew nuts need to be rehydrated after sun drying so that the hard shell will be succulent for ease of cracking after roasting without destroying the innards. Thus, they are placed in humidifier machines that recapture 16 percent of the lost water content on the shells. Immersing them in water for 48 hours is another clear-cut method for humidification.
The next processing step involves putting them on an oil-filled roasting pan at 192° Celsius for 1 and 1/2 minutes. This leads to the spilling of a quarter of the water from the shells. The use of coarse wood particles helps to remove the rest of the water. This makes the roasted shells easy to break.
Shell breaking of cashew nuts is an art by itself and the best of the craft is hand-based. The easiest of all is the use of a wooden implement on the shells after placement on a hammering stone base. The other is a quasi-industrial hand-based method that slices the shells with curved knives that cut along the shells’ curves. Factory methods include centrifugal heaters that crack the hard skin and then lead the contents to a passage filled with air whereby the now light cracked skins fly off leaving the nutty kernels behind.
The packing of cashew nuts takes place after the opened kernels have been dried. After this, the skin of the kernels is removed which leaves the real nuts. The nuts then undergo 8 percent moisturizing in preparation for packing. Packing involves inserting the now moistened kernels in stopper-packets for selling. Each vacuum packet contains carbon dioxide as a filler that creates an extended buffer against the nuts’ spoiling and reduces friction of the contents during conveyance.
For the cashew apple fruit juice to be pure, it needs to be merged with lime juice. This removes any hints of gruesome aftertaste of the juice. Another solution for purification of the juice is steam cooking at 2 percent salt additive. Then the juice becomes clear, pure and tasty and retains its 100 percent natural quality.
The best storage temperatures for unprocessed cashew nuts and apples is 0° Celsius which allows them a 14-day shelf lease. They only keep for 1 day at other temperatures. The apples also need conservation in film-lined bags to reduce dehydration.
African Countries Cashews overview
Africa has the leading producers of cashews in the world but processing is at a low development stage. For instance in 2012, West Africa produced an average 700 million kilos of the nuts while East Africa had 200 million kilos but just up to 50 million kilos underwent local processing. The rest went to the Indian subcontinent and Vietnam for processing. The biggest markets for Africa are therefore also producers, including Asia, with China having a major importing stake.
Kenya is approximately the 16th leading exporter of cashew nuts with 30,000 tons worth of exports in 2016. It tied the position with countries like Togo in West Africa and Indonesia in south-east Asia which produced a similar volume in the year in question.The country’s season falls at an ideal period of between October and December when most of the northern latitude countries have diminished their supplies. The main growing areas include the Coast in Taita Taveta area.
In Tanzania, cashew nuts form a significant part of export revenue as they contribute up to 15% of the foreign exchange of the nation. Tanzania also ranked at position 8 in global production and position 4 in the continental output of the crop in 2011 and went up to position 6 in 2016. The origin of the nuts were in precolonial times but the commercialization of the sector did not start until the mid-20th century. Poverty in farming belts like Mtwara, which contributes 70% of cashew sales in Tanzania helped the sector grow due to ease of cultivation compared to other economic activities.
In its first best year of this decade in 2011, Tanzania exported 113, 374 metric tons of the crop out of a total production capacity of 121,135 metric tons. The East African nation exports more unshelled than shelled nuts. Its biggest export destinations by size using 2011 statistics was India at 83 percent of sales, the US, the UAE and Kenya, each having between 5 and 2 percent worth of imports. In 2016, the country had reached 170,000MT in production of the nuts.
Nigeria was the seventh world exporter of cashew nuts in 2016 with a production tonnage of 190,000 tons. The crop first came into the West African country in the 1400s and 1500s through explorers from Portugal. Due to its northern latitude placement, the country harvests its cashews in the first quarter of the year from January through April.
In Mozambique, the cash crop became a wonder crop at its introduction by the Portuguese in the 1500s. It rapidly formed forest belts that have never diminished since then. The tree grow in the saline coastal belt at as low as 500mm and average 900mm annual rainfall. In 2016, the country was the 10th world exporter and the 7th producer in Africa. Its harvesting periods revolve from October to January each year.
With a harvesting season of March to midyear, Guinea Bissau ranks as the fifth world producer and the third African exporter of cashew nuts. The first appearance of the crop in the West African nation was in the 19th century when the Portuguese planted the first tree. It was however not until 1985 that small-scale farmers took over the cultivation of the crop.
In Guinea Bissau, cashew nut farming is the equivalent of the lief or land ownership system of Europe in the Middle Ages. A farmer with the largest share of the crop in the villages commands much respect. The more plants one has the more wealth the villager commands in a typical farming village.
The country has bloated its output from a mere 150 tons of cashew nut exports in 1966 to 150,000 tons in 2010. There has been rapid adoption in the growing area. In 1978, the hectarage under the nuts was 14,000ha but by 2012 this had reached 223,000ha. The local denomination for would-be importers from Guinea is the Guinean CFA Franc.
Ivory coast is the world leader in the production of cashew nuts. In 2011, the production levels reached 385 million kilos, more than half the 700 million kilos for the West African region that year. By 2017, estimates by Reuters put the production levels to reach 715,000 tons for the country alone. Like the rest of northern latitude countries, the season for the crop in Ivory Coast falls between February and May each year.
African countries’ Export Window
Here is a tabular representation of the main production seasons in Africa, versus those of other world growers.
| Country in other part of the World | World Production Rank 2016 | Harvesting/Export Season |
| Vietnam | 3 | February to May |
| India | 2 | February to May |
| Cambodia | 12 | January to June |
| Brazil | 4 | Jan-Feb, Sep-Dec |
| Indonesia | 17 | July to December |
| African country | ||
| Ivory Coast | 1 | February to May |
| Nigeria | 7 | January to April |
| Guinea Bissau | 5 | March to June |
| Tanzania | 6 | September to December |
| Kenya | 16 | January, October to December |
| Mozambique | 10 | January, October to December |
| Benin | 8 | January to April |
| Ghana | 9 | February to May |
| Burkina Faso | 11 | February to May |
| Senegal | 13 | March to June |
| Mali | 14 | February to May |
| Guinea | 15 | February to May |
As the table above indicates, the bulk of the production timeline for both world and African suppliers falls in the first six months of the year. Thus, countries with peak periods of cashew nut harvests at the end of the year such as Mozambique, Kenya and Tanzania and partially Brazil and Indonesia have export windows.
Generally, the world of cashew nuts is concentrated to the north of the equator. The regions produce 80% of worldwide supplies and wrap up their operations by the middle of every year. From then on the southern parts of the world satiate the global demand up to December. It is notable that the bulk of producers north of the Equator are from Africa, with Nigeria, Ivory Coast, and Guinea Bissau being in the top 5 of global producers.
With an output of 170, 000 metric tons in 2016, Tanzania is the global leader in terms of cashew nuts production south of the equator. Its season also falls favorably at the end of the year similar to that of Kenya, its northern neighbor. Mozambique is the second highest producer in the southern hemisphere. In 2016, the southeast African county produced 85,000 metric tons of the crop.
Generally, despite the major gains there are always huddles that face the sector in Africa. For instance in 2017, estimates of black market or unaccounted for cashews from the globe’s number one exporter, Ivory Coast hit a hundred thousand tons. This is a seventh of the country’s total production. In Kenya, labor payments are low at KSH20 ($2) for each kilo while in Tanzania the transportation from the farm is a tasking.
Summary
Therefore, the importance of cashew nuts in Africa cannot be underestimated. Not only is it an essential fruit for juice making in its succulent form, but the main nut is a world beater in popular consumption. While many African growers consume the nuts locally after roasting them into a sumptuous ivory color, the bulk is processed in foreign countries after shipment. The leading consumption markets in the world for the African, Indian and Brazilian nuts include China, the EU, Russia and North America.
It is also clear that nuts are not the only end-products. The cashew nut shell is a source of biofuels and produces oil for making paints. The kernel also serves as traditional medicine in various communities. This is due to the antioxidants at the core of the nut including Glutathione that fight free radicals. Indeed, there is more to the kidney-shaped, ivory-hued nut than meets the eye!
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