During the wine fermentation process, the pectin on the grape skins will be hydrolyzed into methanol.

Excessive temperature will accelerate the hydrolysis of pectin to produce methanol. People usually start brewing wine in August or September, when the temperature is high. Industry has special temperature control devices to limit the production of methanol. However, it is difficult to control the temperature when making wine at home, which increases the risk of methanol exceeding the standard. ?

When wine is produced industrially, the methanol content is generally reduced through pre-treatment, improved bacterial strains, and improved processes. As for home-brew wine, due to the influence of technical conditions and knowledge level, the methanol content in the home-brew process is often uncontrollable, which may cause higher risks. Home-brew wine should not be drunk openly.

Extended information

Preventive measures: Strictly ensure the quality of the grapes used for fermentation, exclude stale grapes, and strictly control the temperature according to the type of grapes. Early stage of fermentation.

When Saccharomyces cerevisiae does not multiply in large numbers, the alcohol concentration of the fermentation product can be appropriately increased. For example, sulfurous acid can be added at a ratio of 100 mg per liter of grape juice to reduce bacterial contamination and inhibit methanol production.

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