If the color of the wine is only yellowish and there is no other peculiar smell, it will not affect the consumption. This may be caused by poor disinfection in the production process, for example, the hands are not cleaned, or the microorganisms on the utensils exceed the standard. If it is yellow and tastes obviously sour, it means that microbial miscellaneous bacteria are over-fermented. At this time, it is best not to eat.

In addition, fermented grains will turn yellow if they are left for too long. This is because fermented grains are transformed from starch into fermentable sugar, and then into alcohol to produce organic acids through a series of extremely complicated biological and chemical processes under the catalysis of Aspergillus, yeast and other biological enzymes. At the same time, through the decomposition of protein, fat and other substances, nitroaldehydes, higher acids, lipids and other substances are produced. The yellowing of old rice wine during storage is a metabolic process of microorganisms, which is caused by food browning. It is also called Maillard reaction, that is, nitroaldehydes such as protein and nitroaldehydes react with sugars and fats to form ketones.

Reducing agent is the main substance of Maillard reaction. Maillard reaction can occur when the temperature is 20-25℃ and the water content is 10%- 15%, and the speed increases above 30℃. Therefore, it is normal for yellow rice wine to turn yellow after a period of time. Although it has a slight impact on the appearance, it actually tastes more mellow and sweet, and it is safe to drink Huang Jun's rice wine during the shelf life.