Soy has a long history in Asia, where it has been cultivated for thousands of years. It is commonly used as a staple food, because in addition to providing nutrition, soybean plants also act as nitrogen fixers, helping to repair and rejuvenate the soil they grow in. It was introduced to the Western world in 17th century in the form of soy sauce, a fermented condiment, and cultivation of the beans began shortly thereafter. Although it is used to make a variety of facsimile foods for vegetarians and vegans, there are numerous traditional Asian foods made with soybeans that.
The most famous soy product is probably soy sauce. This sauce actually comes in a variety of flavors and types, which are distinguished on the basis of age and flavor additions. It is a fermented product, which is made by soaking beans in a mold starter and then adding a brine and yeast solution. The resulting mixture is set aside to ferment for a minimum of six months before being strained and bottled. Depending on how long the mixture ferments, what is added to it, and the types of cultures used, the flavor will be radically different.
Most Western consumers are familiar with soy milk, which is made by grinding dried soybeans with water and straining them. The resulting liquid is known as soymilk, and can be flavored to taste or consumed plain. Soymilk is welcomed by the lactose intolerant, because it is an excellent milk alternative. A popular soymilk derivative, tofu, is made by curdling soymilk with warm water and enzymes, then straining and pressing the resulting curds.
Some consumers are also acquainted with tempeh, a product which orginates in Indonesia. Tempeh is made with whole soybeans, which are cooked, cracked, and fermented with a special tempeh starter. Fresh tempeh often has a white slightly fuzzy edible caul as a result of the fermentation process. Tempeh itself has a slightly sour, slightly beany flavor which works well in stir fries as well as grilled, steamed, baked, or boiled. Some people who have difficulty digesting soy have an easier time with tempeh, because the fermentation makes it easier to digest.
Another common Asian soy ingredient is edamame, which is made from very young soybeans. The beans are picked while they are still tender and flavorful. In areas where soybeans are cultivated, fresh edamame is available; in other regions, a frozen version from parbroiled beans is obtainable. Edamame can be eaten plain, although they are also added to salads, soups, stir fries, and sweets. The flavor is fresh and spring like, making edamame a popular summer food in many parts of Asia.