The white film on the surface of home-brewed wine is called acetic acid bacteria.

Acetic acid bacteria are harmful bacteria floating in the air. Acetic acid bacteria have a serious impact on the quality of home-brewed wines. Moreover, when acetic acid bacteria contamination occurs in home-brewed wines, it is irreversible and there is no way to do it. It can be saved. Even if the white film is artificially filtered out, white film will continue to grow on the surface of the home-brewed wine within a few days.

As the storage time of home-brew wine increases, the white film will become thicker and thicker, and will gradually cover the surface of the home-brew wine liquid. Acetic acid bacteria or mold cause the wine to lose its luster, become turbid in color, have cloudy or floc-like sediments, snow-like floating objects, etc. These impurities are not only difficult to remove, but also imply that the wine has been irreversibly damaged. Acetic acid will contaminate the home-brew wine, affect the taste and quality of the home-brew wine, and make the home-brew wine impossible to drink normally.

Extended information:

First, if there is a large amount of sediment at the bottom of the wine, and the wine body does not have any pleasant aroma, but instead smells like soy sauce or pickles, then It means that this bottle of wine has been over-oxidized and is not suitable for continued drinking.

Secondly, the microbial control of some wines is not strict during the production and filling process, and there is contamination by miscellaneous bacteria, such as acetic acid bacteria or mold, causing the wine to lose its luster, become turbid, cloudy, or Flocculate sediment, snowflake-like floating objects, etc. These impurities are not only difficult to remove, but also imply that the wine body has been irreversibly damaged.

Thirdly, if there is a type of wine that retains residual sugar, if it is not filtered sufficiently before filling, a very small amount of yeast will remain. After a certain period of time, a sediment similar to wine lees will appear at the bottom of the bottle. This type of wine is suitable for drinking as early as possible when it is fresh. If it is stored for too long, the sulfur smell and yeasty smell brought by the yeast when opening the bottle will cover up the fruity aroma of the wine, and it is not suitable to continue drinking.

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