The next compound I want to talk about is sugar. (And not just because I am majorly jonesing for any and all sweet desserts.)
Sugar is essential to making any type of alcoholic/fermented beverage, but it is also a key characteristic in choosing grapes to make wine.
Technically you can make wine from any type of fruit, but one of the reasons grapes are the most successful choice is due to the exceptionally high sugar content of their juice. Understanding how this sugar develops in a grape and then how it is used in wine making can help you quite a bit when figuring out what a wine will be like.