The sour taste of sweet wine may be caused by two reasons: one is improper links in the brewing process, and the other is improper preservation methods. Some corrupt bacteria multiply and eventually produce organic acids such as lactic acid and acetic acid in the wine, so it will taste sour. Homemade liqueur is an open operation, and it is easy to be contaminated with miscellaneous bacteria in such an operating environment. The most important miscellaneous bacteria is lactobacillus, which is an anaerobic bacteria, and can transform the sugar in the sweet wine into lactic acid, thus making the sweet wine sour.
Cover the stirred rice with a layer of gauze and put it in an environment of about 20 degrees for fermentation (when it is cold in winter, you can put the stirred rice and the container in a pot with water for heating). After about a day or two of fermentation, you can smell the taste of white wine. Put the soaked glutinous rice into a steamer and smooth it, and insert a few holes with chopsticks to facilitate steam convection. Boil water on high fire, and then steam it on low fire for about 40 minutes. After the glutinous rice is steamed, pour it into a clean container, loosen it while it is hot, and air it to about 35 degrees.
The most common reason why glutinous rice wine turns sour is temperature. If the temperature is too high, the fermentation process will start to multiply before the alcohol bacteria are produced, and a lot of acidic substances will be produced at the same time. When the alcohol content reaches 10 degree or above, the acidity will be reduced. Then, seal the lid with plastic wrap, seal it with a plastic bag outside, and wrap it with a piece of cotton like a quilt and put it here. The fragrance will come out when the room temperature is about 36 degrees.