Fermentation is under the action of yeast, the sugar in grape skin juice generates alcohol and carbon dioxide. The pre-fermentation process of red wine is that the skins and juices are mixed together, and yeast has been inoculated in the juice when the grapes are broken. Because there is yeast in the frost on the grape skin, it is not necessary to add yeast to the homemade wine when fermenting.

The optimum fermentation temperature is 15~25℃ and should not exceed 35℃. However, when fermenting in a small container, the heat dissipation is relatively easy, generally not exceeding 32℃. After the peel juice is put into the container, it usually takes one day to start fermentation. Yeast is facultative anaerobic and produces alcohol when oxygen is insufficient, so it should be kept sealed to make fermentation more vigorous.

Extended data:

Relevant professional departments analyzed the samples of homemade wine, and the results showed that the samples contained different concentrations of methanol and fusel oil. The production of methanol and fusel oil mainly comes from raw materials.

On the one hand, the pectin in grape skin is decomposed into methanol under the action of pectinase or heat energy, and mildew will also produce a lot of methanol. The more thorough the fermentation, the higher the methanol content. On the other hand, protein in grapes is hydrolyzed into amino acids, and then fusel oil is generated under the catalysis of enzymes.

In addition, a lot of gas will be produced during the fermentation of homemade wine. Do not use plastic bottles, stainless steel, aluminum utensils, etc. To avoid chemical reactions. Be careful when brewing and drinking by yourself to avoid harmful substances from causing harm to the body.

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People's Daily Online-Homebrewed wine should be drunk with caution, and four minefields should be avoided in daily drinking.