Douchi

Douchi is a type of fermented and salted black soybean most popular in the cuisine of China, where they are most widely used for making black bean sauce dishes.

Douchi is made by fermenting and salting black soybeans using Qu (Chinese: 麹; pinyin: Qū), which is similar or identical to the Miso ferment, Koji. Douchi can be classified as Aspergillus-type Douchi, Mucor-type Douchi, Bacterial-type Douchi, or Rhizopus-type Douchi. There are two main stages to the Douchi making process; first you make the Koji, then there is a prefermentation stage. There can also be a maturation or post fermentation stage, were the Douchi is mixed with other ingredients, like brine, and allowed to age. The black type soybean is most commonly used. The process turns the beans soft, and mostly semi-dry (if the beans are allowed to dry). Regular soybeans (white soybeans) are also used, but this does not produce "salted black beans"; instead, these beans become brown. The smell is sharp, pungent, and spicy; the taste is salty, somewhat bitter and sweet. The product made with white soybeans is called mianchi.

Douchi, "Chinese salted black beans", and "black soybeans" are not the same as the black turtle bean, a variety of common bean that is commonly used in the cuisines of Central America, South America, and the Caribbean.