If you have spent any time around wine bottles, you will have noticed the number on the labels declaring its wine alcohol content.  The number is listed as a percentage and reads something like 13 % Alcohol by Volume or ABV.  What does a wine alcohol’s content really mean? And why do some wines have a higher content than others?

To answer that question, let’s first look at how a bunch of grapes becomes an alcoholic beverage.  This knowledge won’t make you a wine connoisseur, but it will make you very interesting to talk to at parties. We hope. This blog can’t work miracles, so you’re on your own with the delivery. Back to our bunch of grapes. As those little orbs ripen on the vine, they produce sugar. Have you ever bitten into a sour grape? That would be an unripe grape with high levels of acid and low levels of sugar. The longer the grape hangs around on the vine, the lower the acid levels drop and the higher the sugar levels rise. This process, for those of you who really want to sound like a somm, is called veraison.

When those grapes are nice and sugary and ripe, Winemakers collect and crush them, releasing all those sugary juices. If left on their own, natural yeasts in the air will eat up all the sugar and turn it into alcohol. This is called fermentation and it can take anywhere from 10 days to more than a month.

If you happen to be sipping wine and after one glass, maybe two, you’re ready to tell the people you just met thirty minutes ago they can use your vacation home or borrow money, you are most likely enjoying a vintage derived from very ripe grapes. The riper a grape is harvested, the higher the alcohol content a wine will have. Grapes with higher sugar content have more food to feed the yeast, so more alcohol results. Picture little yeast monsters gobbling up sugar and excreting alcohol. Second thought, don’t picture that, it’s gross. Moving on; if fermentation goes on unchecked, the yeast will convert all the sugar into alcohol and a dry wine emerges. Winemakers will stop fermentation earlier to preserve some of the sugar and create a sweeter wine.

As we mentioned, a wine’s alcohol by volume (ABV) is found on the wine label. But what if you have a glass, the bottle is nowhere to be found and you’re wondering about its alcohol content? Look at the wine itself; more specifically, it’s legs.  Wine legs are nothing more than the droplets of wine that form on the inside of a wine glass. To test the legs, hold your glass of wine at an angle so that it can flow up on side of the glass.  Then tip it back to level and watch to see how the wine flows.  A thicker, stickier wine is said to be more viscous and probably has a higher ABV. Look at the droplets that form in the glass after you tip your glass. If you see a lot of legs, you know the wine has a higher alcohol content.

Lower alcohol wines, those with an ABV of 12.5 percent or lower, include varieties of White Zinfandel, German Riesling and sparkling wines. Most wines, both red and white, fall into the medium alcohol content category (12.5-13.5 percent), including Italian Pinot Grigio and Rose’s from France and Spain. Medium-high wines (13.5-14.5) would typically include Pinot Noir, Malbec and Merlot and Italian Barolo.  Some examples of high content wines, those above 14.5 percent, would include California Zinfandel, Petite Sirah, Madeira and Italian Amarone.

Other than wanting to get the party started (heh, heh, heh), why would winemakers want to create wines with ABV’s higher than 14 percent? Alcohol draws out a wine’s more intense flavors and the famous Parker rankings routinely give the better scores to the higher alcohol wines. And, since advances in science make it possible to ferment grapes much longer to produce higher alcohol content, you have some veritable fruit bombs coming out of wineries. California winemakers have especially jumped on this, producing greater and greater numbers of high alcohol wines.

Not everyone is on board with this. Court Master Sommelier, Gianna Cardinale Gaudini says many famous winemakers and sommeliers are now refusing to produce or include on their lists, wines with an ABV of higher than 14 percent. Besides, wines with a medium range ABV pair more easily with food and you are less likely to offer your vacation home to total strangers after one or two glasses.  Food or in this case—wine—for thought.