IT'S ALL ABOUT THE GRAPE

How you go about making wine from grapes depends on the class of grape you are going to use (see "Grape Classifications").
Some grapes will require only a little dilution with water to get its sharp acidic flavor under control. Others will require none at all. Then there are some that may require as much as three gallons of water for every 5 gallons of wine, such as in the case with many wild grapes. Not only does the high acid level of the wild grapes require dilution but their excessive, strong flavor demands it as well.
Sugar may need to be added to the juice in some cases. Sugar is what the yeast ferments to make alcohol. When the fermentation is done the sugar is gone. When there is not enough sugar for the yeast, there will not be enough alcohol in the wine.
Certainly in the case of wild grapes sugar will be in short supply and marginally so with some native wine grapes. Sugar will need to be added to these mixes. But, in the case of European wine grapes only rarely is sugar needed.
The point here is that making grape wine is not necessarily about following a recipe, but rather, going through a procedure of adjustments based on the juice that is at hand. The situation can vary dramatically based on the grape so to apply a recipe to all grapes or even a class of grape is not practical.