Wine and concentration
First of all, it must be understood that Wine is a pure beverage product obtained from the fermentation of wine wholly or in part from the juice of fresh grapes, or from a mixture of grape juice and grape pulp pressed into water. It is "An active liquid that can carry disease, can grow old and die".
Yeast that eats sugar turns into alcohol and CO2.
Or to put it briefly: Wine is grape juice that is alcoholic through fermentation.
So the high or low alcohol content in each bottle of wine is due to the high or low natural sugar in the grape juice. Strictly speaking, the sweeter the grape juice, the higher the alcohol content of the wine bottle after fermentation (of course, full fermentation is required) and vice versa, the less sweet grape juice will give the wine a lower alcohol content.