1, methanol exceeds the standard

The production of methanol is unavoidable during the fermentation process of wine, regardless of whether it is homebrew or industrialized production. Because the production of methanol mainly comes from raw materials. On the one hand, the pectin in the grape skins decomposes into methanol under the action of pectinase or heat, and mold also produces a large amount of methanol, and the more thorough the fermentation, the higher the methanol content will be.

2, easy to explode

Grape winemaking fermentation process, the sugar and other substances will be converted into alcohol, and then a large amount of gas will be produced, the gas in the completely closed container more and more, resulting in a huge pressure, once more than the container's tolerance limit, the container will be blown open. Therefore, when people make homemade wine, they should generally leave 1/3 of the space in the container for fermentation and the lid should not be too tight. A container filled with homemade wine is a time bomb.

3, stray bacteria contamination

Toxic substance accumulation due to stray bacteria contamination is a more frequent problem than methanol overload. What we find tasty and delicious, microorganisms likewise. The large amount of glucose in grape berries provides a suitable source of nutrients for yeast, as well as good conditions for other stray bacteria to survive.

Expanded Information

One, soaking

Sorghum is sent to a soaking pool, where it is soaked in water for 24 hours

Two, steaming

After soaking, the sorghum is steamed in a boiler, commonly known as "steaming sorghum rice" for short

Three, cooling

The rice is then cooled to the point where it is ready for cooking. After steaming, the rice is sent to the cold rice machine by conveyor belt, and hulls are added to the rice on the way so that the rice is not too sticky and cooling is accelerated

Fourth, mixing

The cooled sorghum rice with hulls is sent to the mixer, and granulated rice flour is added to the rice mixer to make it mix evenly with the rice and the rice flour, and then it is poured into the fermentation pool

Fifth, fermentation

Throughout the 10-day period, the rice is distilled to produce the liquor. After 10 days of fermentation, the sorghum rice is distilled into a pot of distillation

6. Distillation (First Liquor)

The fermented sorghum rice is manually poured into a distillation pot and distilled into the so-called "First Liquor".

The first liquor is more sorghum-flavored and must be blended to improve its taste and flavor

Seventh, mixing and re-fermenting

The sorghum residue from the first liquor distillation is cooled by adding hulls to the pot, and then adding the powdered rice to the mix, and then sending it into the fermentation tank for 12 days of re-fermentation.

Baidu Encyclopedia - Brewing