Vinegar is an indispensable sour material in people's life, and it also has health care function. The method and principle of home-made vinegar are introduced as follows. Because the raw materials and auxiliary materials for vinegar production come from agricultural and sideline products, this method is especially suitable for rural areas.

The raw materials for vinegar production are dried sweet potato or sorghum, wheat and some auxiliary materials. If 200 kg of dry sweet potato or sorghum and 50 kg of wheat are used as the main materials, the other auxiliary materials are 2 kg of cotyledon, 2 kg of pepper leaves 1.5 kg, 2 kg of sesame seeds, 3 kg of mung beans, 5 kg of ginger 1 kg, 5 kg of sesame flowers, 5 kg of screwdriver, 50 kg of coarse bran and 30 kg of fine bran.

The steps and principles of making vinegar at home are as follows:

First, make music.

1, koji-making time: mid-August, temperature 28-30℃.

2. koji-making step: ① soaking wheat, sesame and mung bean, crushing and steaming. (2) soak Vitex negundo leaves and Zanthoxylum bungeanum leaves for 2 hours. (3) Put all the auxiliary materials into a container, add water and stir until they are held together and fall to the ground. (4) Blocking, that is, putting the stirred distiller's yeast into a mold to block. ⑤ Put the starter on the firewood, cover it with a sack, and put it in the shade for 4-6 days, and yellow-green mold will appear. ⑥ Dry the sake koji. ⑦ Store in a cool place.

Second, fermentation

1. Cook dried sweet potato or sorghum to gelatinize starch. The main change is that the starch in raw materials is converted into dissolved state by cooking, so it can be used by yeast.

2. Air-dry the cooked raw materials to about 25℃, then mix them with the crushed distiller's yeast, put them in a jar and put them on the balcony for natural fermentation. The main changes are as follows: starch produces glucose under the action of starch fermentation in koji, and glucose produces alcohol and carbon dioxide under the action of yeast alcoholase in koji.

The fermentation process is divided into three stages: the prophase of fermentation-the rapid propagation period of yeast. Main fermentation period-the period when glucose is converted into alcohol under the action of alcohol enzyme, and carbon dioxide gas is produced at the same time, and the temperature rises. Be careful not to exceed 30-40℃. The method of mechanical cooling is to stir and ferment with a wooden shovel once a day. In the late stage of fermentation-alcohol reaches a certain accumulation, sugar is basically exhausted and fermentation is slow. The whole process takes about a month. Through alcohol fermentation, the alcohol content in fermented mash can generally reach 7%.

3. Acetic acid fermentation: the fermented mash is evenly mixed with coarse and fine bran, put into a porcelain helmet, put on a heatable kang, and cover with a quilt for acetic acid fermentation. The main reaction is that alcohol generates acetic acid under the action of acetic acid bacteria in koji. Because acetic acid bacteria are aerobic microorganisms, it is necessary to turn fermented grains constantly, reduce the temperature of fermented grains while increasing air, and turn fermented grains once a day. After seven days, when the acetic acid content reaches 7-8%, the fermentation can be terminated with 3% salt. The fermentation temperature of acetic acid is controlled at 28-30℃.

Third, pour vinegar. Soak the fermented mash in water for 20-24 hours, and then pour in vinegar. Finally, the jar was sealed for a month, and it was delicious.