Wine is fermented fruit juice. It can be made from any fruit, from pineapple to peach to pear, though over time, grapes have been singled out as the most successful ingredient.
Sounds pretty easy, doesnt it? Obviously, theres a little more to it, or wed all have a crock of fruit fermenting away in our basements. Only its likely that our basement crocks would do more festering than fermenting, which makes all the difference in the end.
Wine owes its greatness to fermentation: Without fermentation, its just grape juice. Once fermented, formerly staid and straightforward fruit juice becomes complex with different flavors as time, yeast, and chemistry work away. Most strikingly, fermentation makes grape juice alcoholic—not so much to make the head spin after just a few sips, but about 8 to 14 percent alcohol on average, enough to lubricate the tongue and provoke an appetite for food and socializing alike.
If wine averages 8 to 14 percent alcohol, where does that put it in regard to other alcoholic beverages? In the middle, but toward the low end. Beer averages 3 to 6 percent alcohol; fortified wines, like Port, run 1 8 to 21 percent; most hard liquors reach 40 to 50 percent (which equals 80 to 100 proof). Another way to think about it is that a 5-ounce glass of wine, a 1 2-ounce beer, and a 1.5-ounce shot of 80-proof vodka or other spirit all contain the same amount of alcohol.
How does it happen? The short answer is this: A grape is a grape until yeast gets into it. Yeasts are single-celled sugar junkies found on grapes, in vineyards, in wineries, and in the air everywhere. When they get into a grape, they begin to devour the grapes sugar. As they eat, they give off alcohol and carbon dioxide. When the yeasts have eaten all the sugar, or when they’ve produced so much alcohol it kills them, fermentation is complete.
Broken down into its simplest steps, it looks like this:
Sugar + Yeast = Ethanol (alcohol) + Carbon Dioxide
How anyone figured out that this is a good thing when applied to grapes is a mystery that historians, archeologists, and scientists have researched for ages and continue to study.