The black hair of the beans can not be eaten, long black hair may be above the growth of black mold and gray green mold. Soybean paste long hair is divided into two kinds: one after the hair filial piety, soybean paste surface hair is normal, you can peel off the surface of the hair put in the shade can be eaten; the second kind of hair, sauce stinks, or does not stink of all the sauce all long hair, that can not be eaten.

Soybean sauce, also known as soybean paste, soybean paste, with soybeans fried and ground after fermentation and made, is China's traditional sauce. Soybean paste has a strong sauce and ester aroma, and is salty and sweet, and can be used to cook a variety of dishes, as well as being one of the ingredients for making fried noodles.

High-quality yellow sauce is mostly reddish-brown or brown, bright and shiny, moderate viscosity, fresh and mellow flavor, salty and sweet, no odor, no impurities, pure natural brewing without preservatives.