Soaking: Soak glutinous rice in clear water, and the water is 20 cm higher than the rice layer. In winter and spring, the temperature is below 15 degrees Celsius, and it is soaked for 12 hours; Soak for 8 hours above 25 degrees Celsius in summer and autumn. Water must be changed 1 2 times in summer to prevent rice from souring; Steamed rice: Rinse the soaked glutinous rice with water, drain it a little and serve steamed rice. Steam for 10 minute after the steam is fully loaded; Sprinkle a proper amount of water on the rice layer, and then steam until the rice grains swell and shine without sticking to the teeth; Stir-fry: After the rice is cooked, it is washed with clear water to cool down, drained and spread on the bamboo mat. When the temperature drops to 25 degrees Celsius, quickly and evenly mix in the koji powder; Fermentation: put the rice mixed with koji into the jar, add straw mats to keep the jar warm in winter and spring, and keep the room temperature at 25-30 degrees Celsius in summer and autumn. After 36 hours, the liquor oozed out, with golden color, sweet and slightly sour taste and fragrant wine, indicating that the fermentation was normal. Acetalization: During the fermentation process, continue to ferment for 3 days to promote the production of more alcohol. When the liquor begins to turn sour, add 200 kilograms of water to every 50 kilograms of steamed rice to reduce the alcohol concentration of the liquor and naturally vinegar it; Finished product: After vinegar in the jar, it takes 30 days in summer and autumn, and 50 days in winter and spring, and the vinegar will turn sour and mature. The upper layer of vinegar is clear and orange yellow, and the middle and lower layers are milky white and slightly turbid. Mixing the two is white vinegar.