The brewing method of wine is as follows:

1. Natural wine: grape raw materials are completely used for fermentation, and sugar and alcohol are not added during fermentation. Choose the method to improve the sugar content of raw materials, improve the alcohol content of finished products and control the residual sugar content.

2. Fortified wine: After fermenting into the original wine, the alcohol content is increased by adding brandy or deodorized alcohol, which is called fortified dry wine. Adding brandy or alcohol and sugar to improve the alcohol content and sugar content is called fortified liqueur, which is called concentrated liqueur in China.

3. Seasoning wine: it is made by soaking aromatic plants in wine and blending, and belongs to aperitif wine, such as absinthe, clove wine, osmanthus wine, etc. Or tonic wine, such as ginseng wine, is made by soaking medicinal materials in wine and carefully blending.

The key factors of winemaking are as follows:

Effect of temperature on fermentation Yeast can only survive at a certain temperature. When the temperature is lower than 10℃, the growth and reproduction of yeast are very slow. With the increase of temperature, its reproduction speed is accelerated. When the temperature exceeds 35℃, the growth of yeast will be inhibited, and the propagation speed will slow down rapidly. At 40℃, yeast stopped budding and began to die. In order to obtain fermentation broth with high alcohol concentration and reduce alcohol loss, fermentation temperature must be controlled.

Effect of air on fermentation; Yeast needs air to reproduce. In the case of complete isolation from the air, yeast reproduction stopped for several generations. With a little contact with air, yeast can continue to reproduce. Most yeasts will die if there is no air for a long time. In order to maintain yeast fermentation for a long time, a small amount of O2 must be supplied.