Tofu

Tofu (豆腐 or 荳腐 in pinyin: dou4 fu0, �`�부 in Korean), or bean curd, is a food made by coagulating soy milk with calcium sulfate (gypsum), nigari (a sea-salt derived compound rich in magnesium chloride), or other agents, and then pressing into blocks, similar to the way cheese is made from milk. It was first made in China in the second century BC, during the Han dynasty. It was introduced into Japan in the Nara period (late seventh century). Tofu has become a staple in these countries, as well as Vietnam, Thailand, and Korea.

Tofu is frequently associated with vegetarianism and mock meats in the Americas and Europe, as it is a good source of protein. However, its uses extend far beyond that, and it is common in many Asian countries such as Korea. It usually comes packed in water, and comes in two main varieties:

hard tofu (木綿豆腐 momendōfu in Japanese, lit. cotton tofu), which has a firm texture resembling cheese
soft tofu (絹漉し豆腐 kinugoshi tōfu in Japanese, lit. silk-filtered tofu), which has a custard-like texture

Generally, the firmer style is used for kebabs, mock meats, and dishes requiring a consistency that holds together, while the softer style can be used for desserts, soups, shakes, and sauces.

Tofu can be found in Asian markets, farmers' markets, and health food stores, although many large grocery stores also stock it. In Chinese supermarkets, tofu can be found in four to five different grades of firmness and consistency. In the United States market, the largest provider of tofu products is Hong Kong-based Vitasoy International Holdings Ltd., who sell their tofu products under the trademark VITASOY, Nasoya and Azumaya.

The extra firm variety of tofu is often called dried tofu (荳乾) because of its low water content, though it is not completely dry. One variety of dried tofu is sliced into long strings with a cross section smaller than 2mm×2mm. This shredded dried tofu (荳乾絲) is usually served cold like noodles. At the other extreme, the extra soft tofu can be served as a Chinese dessert in syrup flavored with ginger or almond.

Fresh tofu has a sweet fragrance of soy. Tofu can be easily spoiled if not refrigerated properly during transportation; any trace of sour odor or taste is a telltale sign of staleness. Smaller supermarkets tend to sell sour tofu because some don't use refrigerated trucks for delivery like the bigger chain stores. Once purchased, unpackaged tofu should be kept in the refrigerator, in water that is changed once a day. Tofu in sealed package can be kept for weeks in refrigerator.

Tofu is very high in protein and has almost no flavor of its own. This is what makes it versatile; it takes its flavor from whatever is added to it — marinating is a popular way of flavoring tofu. Tofu can be made to taste like cheese, pudding, eggs, bacon, etc. Furthermore, the texture of tofu can be altered to match the above dishes. Tofu's texture is altered by draining, freezing, pureeing, and cooking.

One can also purchase flavored tofu, fried tofu, or dried tofu. One famous Shanghaiese delicacy is stinky tofu, which smells like rotten eggs.