CASSAVA, kiis-sii'va, MANIOC, mani-ok, or MANDIOC, a South American shrub (Manihot utilissinsa) belonging to the natural order Euphorbiacete, sub-order Crotonete. There are two forms, popularly known as bitter and sweet, both of which are widely cultivated in tropical America for their fleshy, cylindrical, starchy roots, which form a large part of the food of the natives, and from which tapioca is made. They have also been introduced into other warm countries, especially Africa, and i have quickly gained important positions as food crops.
The plant, which attains a height and breadth of four feet or more, is rather bushy, since its numerous knotty, brittle, pithy stems have many palmate leaves. The flowers, which appear in midsummer, are green or yellowish and inconspicuous and are succeeded by wing angled capsules. The best results are obtained on light, sandy, well-drained soils. The land is prepared as for corn, but instead of plant ing seed, stem cuttings are covered by the plow, and when the plants appear they are cultivated with the same implements used in corn-growing. In about seven months the white soft roots, which occasionally weigh 30 pounds, and are sometimes three feet long and three inches thick, are dug by hand, washed, grated or ground to pulp. The juice, or poisonous part, is carefully pressed out, and when boiled, becomes the delicious sauce called casareep (q.v.), much esteemed by epicures. The flour that remains after pressure is formed into thin, round cakes and bak.d. To a European accus tomed to eat bread, these, though sweetish and not unpalatable, have an insipid taste. If placed on close vessels, and preserved from the attacks of insects, cassava bread may be kept for several months without injury.
Poisoning by the bitter cassava is due to the presence of minute quantities of hydrocyanic acid (q.v.). This is a very common ingredi ent of many fruits and seeds, but usually is modified as the fruit ripens. The general process of manufacture of cassava destroys or drives off the free hydrocyanic acid.
The natives of South America throw a num ber of cakes of cassava together to heat, after which they soak them in water, which causes a rapid fermentation to take place; and from the liquor thus obtained they make a very sharp and disagreeable, but intoxicating, beverage, which will not keep longer than 24 hours with out spoiling.
From the pure flour of cassava is formed the substance called tapioca, which is frequently used for jelly, puddings and other culinary pur poses. This is separated from the fibrous parts of the roots by taking a small quantity of the pulp after the juice is extracted and working it in the hand till a thick, white cream appears on the surface. This, being scraped off and washed in water, gradually subsides to the bot tom. After the water is poured off the remain ing moisture is dissipated by a slow fire, the substance being constantly stirred, until at length it forms into grains about the size of sago. These become hard by keeping, and are the purest and most wholesome part of the cassava. The starch of cassava, separated from the fibre by the usual processes, is known as Brazilian arrowroot.
The roots of another species of this shrub, called sweet cassava (Manihot aipi), the juice of which is not poisonous, are usually eaten with butter, after being roasted in hot ashes. They have much the flavor of chestnuts, and are an agreeable and nutritive food, containing about 30 per cent of carbohydrate materials. The roots of the sweet cassava are also used as stock-food and to make glucose and starch. Florida is the only State in which sweet cassava has attracted much attention, but it seems to be not very profitable there on account of the high price of labor and fertilizers. Consult United States Department of Agriculture, Bureau of Chemistry, Bulletins 44 (1894), 106 (1907), and Farmer's Bulletin 167 (1903).