Juice is a Must, no pun intended.
The production of wine is a simple scientific process. The fruit juice or the vegetable extract containing natural or added sugar, acid and yeast, ferments, and produces carbon dioxide. This appears as bubbles and escapes into the year. Alcohol is also produced which stays in the wine.
Wine may have anywhere between the up to 17% of alcohol, be sweet, medium or dry and still or bubbly.
It is the percentage of alcohol that determines the strength of the wine. Assuming that the wine is properly made and that fermentation is efficient, then the greater the sugar content, the higher will be the alcohol content, up to the time when the added yeast stops fermentation.
To obtain an alcohol content of 10%, each gallon of prepared juice or extract which is known as “must” will require 1 ¾ pounds of sugar. Add ¼ pounds of sugar for every additional 1% alcohol required.
Dry wines hardly contain any sugar. That is because all the sugar has been used up during fermentation. These dry wines also have a low alcohol content. A much weaker wine than this would not keep well and will have to be drunk when young.
A sweet dessert wine with an alcohol content of 17%, needs more sugar for conversion into alcohol. And as much as 3 ½ pounds of sugar is added for gallon of extract or juice so that when fermentation ceases some sugar is still going to remain.
To produce a rich dessert wine with them. I will call content of more than 17%, it is necessary to fortify the wine by adding alcoholic preparations like vodka at the rate of 2 fluid ounces per 26 ounces of wine. This is definitely not pure wine and is normally used as a herbal tonic.