The wine is fermented 10 to 30 days. Wine fermentation is related to temperature. When the temperature is kept at 15 to 25 degrees Celsius, the fermentation can be completed in about 10 days. When the temperature is low or high, the fermentation time of wine will be longer, generally not more than one month. Fermentation is the use of yeast to produce alcohol and carbon dioxide from sugar in grape skin juice. The fermentation temperature is preferably 65 05℃ to 25℃, and should not exceed 35℃. At the beginning of fermentation, the liquid level is calm. At this time, weak carbon dioxide bubbles have been generated, indicating that yeast has begun to reproduce. After 2 ~ 3 days, a large amount of carbon dioxide is released, and skin residues float to form a hat shape. When you taste the fruit juice, the sweetness gradually decreases and the taste of wine gradually increases.