Manihot esculenta, a tropical root crop which is outranked, in volume consumed, only by the sweet potato. The plant is native to C. or S. America, where it has been in use since prehistoric times, and is the only member of the spurge family, Euphorbiaceae, which provides food. Brazil and Indonesia are the principal producing countries, but cassava has become important in the economies of many tropical countries worldwide. It is marketed mainly in the form of cassava flour, but can be eaten as a vegetable (as can the young leaves) or processed into a wide range of other products.
Cassava tubers are cigar shaped, with a brown, often pinkish, rind which is usually hairy, and ivory white flesh. They vary considerably in size, but are typically 25 cm (10″) long and 5 cm (2″) thick. They are borne in clusters of up to ten, and may spread out widely and deeply from the stem of the plant.
Varieties fall into two main groups: bitter and sweet, of which the first is the more cultivated, although cultivars of the latter are chosen when the plants are being grown for their leaves. The only cassava product with which most people outside the tropics are familiar is tapioca, a refined starch. The cassava plant itself is sometimes known by this name, though the word in its original American Indian usage always meant the prepared product. Other names for cassava often used are manioc and yuca, also of American Indian origin.
The original wild species from which the cultivated one evolved is, or are, lost or unrecognized. Selection of plants for cultivation would have been directed at reducing a serious disadvantage of the plant; that it contains two substances, a glucoside and an enzyme, which react together to produce poisonous prussic acid. The reaction begins, slowly, when the tubers are uprooted and speeds up when they are cut or peeled and exposed to the air. At worst, the amount of poison can be fatal. However, prussic acid is freely soluble in water and driven off by heat, so the American Indians were able to evolve various soaking and heating processes to remove it. It was also the American Indians who bred the two main races of cassava.
Bitter cassava has a high yield of large, starchy tubers but contains an appreciable amount of poison, so that it can be consumed only after thorough treatment. Sweet cassava is of lower yield and its tubers are comparatively watery; but they contain less poison and that mainly in the skin, so that after peeling the tubers may be safely eaten as a cooked vegetable or, less often, raw, and the leaves are safe to use as a vegetable. Nearly all tapioca and other cassava products are made from bitter cassava.
As a staple food, cassava provides much carbohydrate, but very little protein; so in regions where people depend almost exclusively on cassava, malnutrition is common. Nevertheless cassava, properly supplemented with a source of protein, has a unique advantage over other roots. After the roots have grown, which they do quickly, typically in six months, they can be left in the ground for as long as three years without deteriorating. Thus cassava can be a reserve food against shortage.
The first European explorers in the W. Indies found cassava in use everywhere, in the form of meal and of dried, flat cakes. They made use of it themselves on their voyages. Cassava meal, now usually known by the Portuguese name farinha (flour) or the Creole name couac, was made by a sequence of processes which began with grating the peeled tubers and squeezing the moisture from them, and which ended with heating, either briefly to make a porridge or for longer to make a dry meal which would keep for some time.
Cassava continues to be an important food in the Caribbean region. Hawkes (1968), who writes at length on this topic, comments that: ‘Boiled, hot cassava is most often served as a vegetable in the American tropics dressed simply with butter, additional salt if needed, a couple of good grinds from the pepper mill, and a few drops of lime or sour-orange juice.’ His highest praise is reserved for a soup/stew dish of tripe (mondongo) and cassava and 15 other ingredients.
A special cassava product made only in the Caribbean is cassareep. This is a thick syrup prepared by boiling down juice from the tubers with sugar, cloves, and cinnamon. Its unique flavour is essential to the W. Indian stew pepper pot. A corresponding product/sauce, tucupi, plays a similarly important role in Brazil.
In Brazil a superior variety of cassava, mandiba, was ground extra fine, then pressed. Some of the fine starch escaped with the juice; but this was extracted from the liquid (tipioca) and heated to make pellets (tipioceto). That was the origin of the modern tapioca process. However, farinha was the normal everyday product, and still is in regions where cassava is the staple food.
The Indians also made a cassava beer; and they boiled the young leaves as a vegetable, a practice which continues. Like the tubers, the leaves must be cooked to remove poison. The early European explorers brought back only meal, not cuttings from which the plant could be grown, but slave traders later took cuttings to Africa, where the plant was in use by the end of the 16th century. By the late 18th century it had spread to E. Africa and was already a major food in a region beyond the southern limit of yam cultivation.
The usual African practice is to cook the tubers, then pound them to make a type of porridge called foo-foo in W. Africa. Sometimes this is given a short fermentation to improve the flavour. The pulp can be dried to make a dry meal called gari. Cassava also provides beverages, both non-alcoholic ones and beer.
Cassava arrived in the Malay peninsula and Indonesia during the 18th century, and in India by 1800. Neither in India nor in SE Asia did it become as important in diet as in parts of Africa. Much is grown, but most of it is made into tapioca for export. However, in Indonesia, the Javanese, with their customary skill in fermentation processes, have developed a fermented cassava delicacy, tapé, as well as using fermented tuber peelings as a seasoning for rice.
During the 19th century cassava was introduced to the Pacific islands and became an important food in Polynesia. In Hawaii it is often used as an alternative to taro in making the fermented porridge poi.
Alan Davidson was a distinguished author and publisher, and one of the world's best-known writers on fish and fish cookery. In 1975 he retired early from the diplomatic service—after serving in, among other places, Washington, Egypt, Tunisia, and Laos, where he was British Ambassador—to pursue a fruitful second career as a food historian and food writer extraordinaire. Among his popular books are Seafood of South-East Asia, North Atlantic Seafood, and Mediterranean Seafood. In 2003, shortly before his death, he was awarded the Erasmus Prize for his contribution to European culture.
Hawkes, Alex D. (1968), A World of Vegetable Cookery, New York: Simon & Schuster.
