The rice vinegar brewed by this method is brown-black, clear and sour. 50 kilograms of glutinous rice can brew 225 kilograms of rice vinegar, and vinegar residue can be pickled with sauerkraut or mixed with feed to feed pigs, which has good economic benefits. 1. Raw material formula: 50 kg of glutinous rice, 2 kg of distiller's yeast (sweet distiller's yeast or distiller's yeast, when used, ground into powder 1, soaking: the glutinous rice is soaked in clear water, and the water surface is 20 cm higher than the rice layer. When the temperature is lower than 15℃ in winter and spring, soak 12- 16 hours; Soak for 8- 10 hour when the temperature is above 25℃ in summer and autumn. Change the water 1-2 times in summer to prevent the rice from becoming sour. 2. Steamed rice: Rinse the soaked glutinous rice with water, drain the water slightly, and then steam the rice. Steam after the steam is full 10 minute; Sprinkle appropriate amount of water on the rice layer and steam for 10 minute. Until the rice grains are swollen and shiny, loose and soft, and can be chewed without sticking to teeth. 3. Stir-fry: After the rice is cooked, rinse it with clear water to cool down, drain the water and spread it on a bamboo mat. When the product temperature drops to 25-30℃, the koji powder is quickly and evenly mixed. 4. Fermentation: put the rice mixed with koji into a jar, wrap sacks or straw mats around the jar to keep warm in winter and spring, ventilate and dissipate heat indoors in summer and autumn, and keep the room temperature at 25-30℃. After 24 hours, you can smell a slight bouquet; After 36 hours, the liquor oozed, golden in color, sweet and slightly sour in taste, and fragrant in wine, indicating that the fermentation was normal. 5. Acetalization: In the process of in-tank fermentation, continuous fermentation is needed for 3-4 days to complete saccharification and promote the production of more alcohol. When the liquor starts to sour, 200-225 kilograms of clean water is added to every 50 kilograms of steamed rice to reduce the alcohol concentration of liquor, which is beneficial to the reproduction and growth of acetic acid bacteria in the air. 6. Finished product: After the vinegar is put into the tank, it will turn sour and mature for 20-30 days in summer and autumn and 40-50 days in winter and spring. At this time, there is a layer of acetic acid bacteria film on the surface of vinegar, which has a pungent sour taste. The upper layer of vinegar is clear and orange, while the middle and lower layers are milky white and slightly turbid. Mix them evenly, add spiced seasoning and sugar color into white vinegar, precipitate and filter to get fragrant vinegar. Mature vinegar should be stored for 1-2 years.