Renye Fang's mash is a kind of low-degree fermented sweet wine, which is rich in protein, amino acids and reducing sugar, which provides a good nutritional basis for microbial reproduction. Usually, wine contains alcohol, and when the alcohol content is above the threshold of microbial reproduction, it will not be moldy or deteriorated. If your wine package is open or poorly sealed, it will go moldy and deteriorate when the alcohol in it volatilizes below the threshold of microbial growth.

The white film on the surface may be moldy flowers produced by fermented wine, so it is suggested to discard it and stop eating it.