Tofu is made from soybeans seeds. Dried soybeans are soaked in water, crushed, and boiled. The mixture is separated into solid pulp (okara) and soy “milk.” Salt coagulants, such as calcium, magnesium chlorides and sulfates, are added to the soy milk to separate the curds from the whey. In some cases, acid coagulants, such as citric acid, can be used. The soy milk is poured into moulds to allow the carbohydrate-laden whey to drain off. The resultant soft cakes are cut into squares and stored under water until sold in bulk or individual water-filled tubs. Tofu can be made extra soft,  firm, or extra firm, depending on the different methods of production. Dried tofu, which does not require refrigeration, is also sold.
Tofu is 6–8 per cent protein and is high in calcium, potassium, and iron. Okara and soy whey, the by-products of tofu manufacture, are also eaten. The skin that forms on top of the soy milk as it stands is removed and dried in sheets for use in vegetarian dishes. Tofu may be flavoured, such as with ginger or onion, or seasoned with spices. It can be grilled, deep-fried, simmered, stir-fried, steamed, or eaten fresh. In China, fermented bean curd is highly popular. Chinese tofu usually has a somewhat firmer texture and a more-pronounced taste than that favoured in Japan.