Alcohol is the natural by-product of fermentation—mash some grapes in a barrel, wait a spell, and voilà! Booze. It's created when the grape's natural yeast feeds on the sugar, resulting in equal parts carbon dioxide and ethanol (the type of alcohol that makes you tipsy). Most table wines naturally range from 7% to 14% alcohol by volume, depending on the amount of natural sugar in the grape varietal or the amount of sugar added by the vintner in a process called chaptalization. Grapes grown in cooler climes have less sugar and thus create less alcohol. This doesn't necessarily make a wine better or worse, but alcohol is definitely crucial for the development of a wine, acting as a preserver while adding a sense of sweetness, strength, weight, and character.