Bean vector is "lobster sauce". Douchi (sound chǐ) is a kind of food made by soaking soybeans or black beans and steaming (boiling) and fermenting them. It is mainly produced in Liuyang, Hunan.

Douchi can be divided into "black bean Douchi" and "soybean Douchi" according to raw materials.

Douchi can be used not only as seasoning, but also as medicine. Traditional Chinese medicine believes that douchi is flat in nature and slightly bitter in taste, and has the effects of sweating, relieving exterior syndrome, clearing away heat and penetrating rash, relieving restlessness in the middle warmer, relieving depression and detoxifying, and can be used to treat common cold and headache, chest tightness, nausea and vomiting, typhoid fever, food poisoning, etc.

Douchi is widely used in cooking in China. Douchi can be mixed with spices such as sesame oil as a side dish; Cook dishes with lobster sauce and tofu, eggplant, taro, radish, etc. Have different flavors; The famous "Mapo Tofu" and "Fried Pork" all use lobster sauce as seasoning. Cantonese people prefer to use lobster sauce for Cantonese cuisine, such as "lobster sauce ribs", "lobster sauce herring" and red-cooked chicken, duck, pork and beef. Especially when the snails are fried, it tastes better.