The degree of wine reflects the alcohol content, which comes from the sugar in grape juice during fermentation. Sugar is converted into alcohol and carbon dioxide gas by yeast. If there is enough sugar, when the alcohol content reaches about 16 degrees, because it exceeds the tolerance of yeast, alcohol will kill the yeast and naturally stop the fermentation broth.
If there is sugar left, the wine is still sweet, but the alcohol content will be higher. If there is not enough sugar, the yeast will convert all the sugar into alcohol.
Wine fermentation can last for 7- 10 days, and the specific time is determined by grape varieties, sugar content and fermentation temperature. To determine the separation time. After a period of intense fermentation, the amount of bubbles is greatly reduced or disappeared. When the strong wine smell and sweetness disappear, it can be filtered. Too long will make the alcohol content higher.
Extended data:
The misunderstanding of homemade wine
Myth 1: Grapes are brewed for a long time. Grapes are not easy to preserve at room temperature and are prone to mildew. If the freshness is not high, it will make the wine more moldy.
Myth 2: the brewing container is not suitable. It is best to use non-metallic utensils, such as glass bottles and jars, for homemade wine.
Myth 3: Throw away the grape skins quickly. At the beginning of fermentation, the grape skin, pulp and stone should be kept together for a few days to three weeks, and then the above things should be bottled and sealed separately.
Myth 4: Add sugar to wine. Too much sugar in wine will do some harm to human body.
Myth 5: add white wine.
Myth 6: Fermentation time is too short.
References:
Baidu Encyclopedia-Homemade Wine