1. The most common raw materials are corn, bean skin and other raw materials with high starch and sugar content, mixed with about 1 kg, added with 1 g of vinegar koji, and inoculated at a temperature below 4 degrees.

2. Crush and steam. Generally, substitute brewing must go through the process of crushing and then steaming. Increase the microbial contact surface of raw materials, which is beneficial to fermentation and gelatinization of raw materials, and accelerate saccharification.

3. stew the steamed raw materials for 15-2 minutes, and then spread them out. When the air temperature is below 4℃, add vinegar koji, and turn it over for 2-3 times to make it even. When the temperature drops to 17℃-18℃, vinegar can be made manually. Lower temperature can make saccharification and sprinkling fermentation complete. Alcohol production is high. It can inhibit miscellaneous bacteria and improve the quality of vinegar.

4. Fermentation in the jar. Put the koji into a fermentation tank or jar for fermentation. The early stage is saccharification and alcohol fermentation. (At this time, the temperature of starter cultures before adding vinegar) is required to be 28℃-3℃, and after 36 hours of fermentation, it is better to raise the temperature of the product to about 39℃. At the same time, turn it evenly. And adding chaff to increase the degree of vegetable loosening, oxygen supply and temperature increase, so as to facilitate vinegar. After about 7 days, the temperature began to drop. It shows that alcohol oxidation ends and vinegar begins.

5. dilute 5g of acetic acid bacteria with water, then evenly sprinkle them into the fermented materials after alcoholization and stir them evenly. You can also add water into a small amount of wheat bran, soak it with water, and add it to the fermented material after alcoholization.

6. Keep the temperature at 2-43℃ and the water content at about 55%, and ferment for 5-15 days (the lower the temperature, the longer the time). When the acidity reaches the maximum value by pH test paper, the acetic acid fermentation ends. If it is liquid aeration fermentation, it can be fermented for 3-4 days. Natural fermentation takes a long time. In the process of normal temperature fermentation, pay attention to frequent turning or stirring, and keep it moist.

7. Acetobacter is aerobic, so the container cannot be sealed during acetic acid fermentation. It can be sealed with multiple layers of gauze, or covered with a loosely sealed cover, and sealed after turning. The end point of acetic acid fermentation is in the state of PH less than 3, and the acidity is not increasing, and there is no or almost no alcohol smell, which can be considered as the end of acetic acid fermentation.

8. After acetic acid fermentation, in order to prevent the peroxidation of acetic acid, 2%-3% salt should be added to end the fermentation, and then it should be sealed for a period of time for post-ripening or aging for storage. When you need to eat, you can add 5 times as much water as the raw materials, soak the vinegar for more than 24 hours, and pour out the vinegar solution for filling.