2. Add an appropriate amount of rock sugar, with the ratio of 10 kg of grapes plus 2 kg of rock sugar or white sugar. After adding sugar, various enzymes in grapes can react and finally produce glucose. The more sugar, the more alcohol is produced. So it is necessary to put sugar in homemade wine. After the bottle is full, seal it with plastic wrap, cover it tightly and put it in a ventilated and cool place for fermentation.