The Chinese name for fermented dried black soybeans used as a seasoning is douchi. Also called fermented black beans or salted black beans, douchi is a pungent, salty ingredient used in small amounts to add deep umami flavor to Chinese dishes.
Traditional production begins with cooked black soybeans, which undergo natural mold growth and fermentation. The beans are then salted, and they may be matured in brine or with additional ingredients. The finished beans are soft to semi-dry, dark in color, and intensely savory, with salty, bitter, sweet, and sharp notes.
Douchi is especially common in black bean sauce, steamed fish, steamed spare ribs, stir-fried vegetables, and mapo tofu. It is usually chopped, mashed, or combined with garlic, chili, oil, or soy sauce before being added to a dish. Unlike natto or tempeh, it is generally treated as a condiment rather than eaten as a main portion.
Douchi is not the same as the black turtle bean used in Latin American and Caribbean cooking. It is also distinct from Korean doenjang and Japanese miso, which are fermented soybean pastes. Historical evidence places fermented black soybeans in China at least as early as the Han period, including finds associated with the Mawangdui tombs sealed around 165 BCE.