This is because the alcohol is not tightly closed in the fermentation process, and there is oxygen, which oxidizes ethanol into acetic acid, so it has a sour taste.

Normal alcohol will not have a sour taste. If it has a sour taste, it is abnormal, and it can't play a role in disinfection. Therefore, it is not recommended, and if you want to use alcohol for disinfection, you must choose 75% alcohol.

The difference between edible alcohol and medical alcohol;

1, the main component of medical alcohol is ethanol. Medical alcohol is made from starch plants through saccharification, fermentation and distillation, which is equivalent to the process of making wine. However, the distillation temperature is lower than that of wine, the times of distillation are higher than that of wine, the alcohol content is higher and the output of finished products is higher. There are more ether and aldehyde components other than alcohol than wine, so it can not be drunk, but it can be used for human health. It belongs to plant raw material products with a general concentration of 75.

2. Edible alcohol, also known as fermented distilled liquor, mainly uses potatoes, grains and sugars as raw materials to obtain water-containing alcohol for food and industry. Its flavor features are divided into four parts: color, aroma, taste and body, which means the contents of four main impurities in distilled liquor. Different tastes and gases will make the flavor of distilled liquor different.

Low concentration of edible alcohol can't achieve disinfection, so don't choose edible alcohol for disinfection at home.

The difference between medical 75% and 95% alcohol;

1, the main component of medical alcohol is ethanol, so the fundamental difference between 75% and 95% alcohol lies in the different content of ethanol. 75% alcohol contains 75% ethanol and 25% water. 95% alcohol contains 95% ethanol and 5% water.

2. The ability of disinfection and sterilization is different. 75% of medical alcohol has protein coagulation and penetration effect, and the disinfection and sterilization ability is the strongest; However, 95% alcohol forms a protective film on the surface of bacteria because of its high concentration, which prevents it from entering the bacteria and is difficult to kill the bacteria completely.

3, different uses, 75% alcohol is mainly used for disinfection, can contact the skin surface; 95% alcohol is mainly used for cleaning, such as wiping lenses, wiping ultraviolet lamps and bottle caps. You can add distilled water or boiled cold water to 95% alcohol and dilute it to get 75% alcohol.