The hanging cup of wine cannot be directly equated with the quality of wine, but it can directly reflect two problems: one is the viscosity of wine, and the other is its surface tension.

The viscosity of wine means that there are not only alcohol and water in wine, but also other trace substances, such as sugar and glycerol, which will directly affect the viscosity of wine. Alcohol content affects the surface tension of wine. The higher the alcohol content, the faster the wine volatilizes, so the greater the surface tension of the wine, the stronger the adhesion on the glass wall. Therefore, the higher the sugar content, glycerol content and alcohol content of a bottle of wine, the better the hanging cup of wine.