James T. Lapsley, Ph.D, a Professor of Viticulture at the University of California, Davis—who co-authored a 2011 paper on the subject for the Journal of Wine Economics, tellingly titled “Too Much of a Good Thing?”—claims that the grape sugar levels in wine have increased between 7 and 10 percent over the past few decades.
“A 10% increase in sugar concentration would result in 10 percent more alcohol,” says Lapsley. “I don’t think that has a huge health impact.”
As long as you drink moderately (a glass or two daily), that’s likely true, though metabolizing ethanol in alcoholic beverages produces acetaldehyde, a toxic chemical thought to be a carcinogen in humans.
So what does sugar have to do with a wine’s alcohol level? During the process of fermentation, natural yeasts in the environment break down the sugars in the juice released by the grapes when crushed.
The yeasts then convert the sugars into alcohol as well as carbon dioxide, which generally dissolves in the bottle.
Likewise, the longer a grape ripens, the more sugar it’s apt to develop. When there’s more sugar, the yeasts have more to convert, which results in more alcohol.
Don’t blame the grape, though, for the rise in alcohol. Instead, says Seattle-based certified sommelier Yashar Shayan, the rise can at least in part be attributed to the consumer.
“People like it,” he says. “They may claim they don’t, but they do.”
It’s not dissimilar from how people say they want to avoid sweet foods, “but then they consume plenty of cola, ketchup, and other processed foods which are loaded with sugar,” says Shayan. “The consumer likes the sweetness.”
Mark Aselstine—the founder of Berkeley-based Uncorked Ventures, a wine of the month club—points to the dominance of wine reviews published by The Wine Advocate and its founder, lauded critic Robert Parker, for pushing the trend of higher-alcohol wines by often rewarding them with high scores.
“Parker, generally speaking, enjoys higher-alcohol content in his wines than the higher acidity and more austere versions of generations past,” says Aselstine. “As his reviews became more and more popular, and as retailers increasingly used scores to do their jobs for them, vintners started trying to hit that style with at least some of their offerings.”
Many wine professionals point to climate change as helping heat up the “hotter” wine trend. The warmer the weather, the more sugars in the grape that are converted to alcohol during fermentation.
Shayan also believes that, in the United States at least, viticulturists are choosing to plant in hotter regions because vineyards in dry places are easier to manage than those in cool, rainy places.
The economic climate is another contributor to alcohol percentages.
The U.S. has a thirst for cheaper wines. Most Americans spend less than $10 a bottle, says Keith Wallace, president and founder of the Wine School of Philadelphia and author of Corked & Forked: Four Seasons of Eats and Drinks.
“To mass-produce wines that are inexpensive and tasty, a winery has to use cheap grapes. Unfortunately, those cheap grapes will make lousy wine—they are cheap for a reason,” says Wallace. “To make these wines taste good, the winery will add a grape concentrate called Mega Purple to the vat.”
Mega Purple and its close relative Ultra Red not only impart more color, they can also introduce additional sugar.
When this occurs during fermentation, those sugars can convert into slightly more alcohol. Also, higher alcohol content can mitigate a wine’s acidity and adversely affect its flavor profile.
“You start to lose acidity, which you need to make a wine balanced—or not taste like alcoholic grape juice,” says Elizabeth Schneider, a certified sommelier and co-host of the podcast WineforNormalPeople.com.
“High-alcohol wines will seem hot going down, like a shot,” she says. “Without the mitigating forces of acidity or tannin, which are sometimes diminished in the over-ripening process, you get a wine that is all fruit and alcohol.”
That said, some industry veterans predict a sea change in upcoming vintages, with a general trending-down of alcohol percentages.
A gradual shift in consumer taste, or at least in markets whose palates have developed toward more nuanced wine, is likely to drive the decrease in alcohol. A larger part of the market is becoming more discerning.
Another reason for the downturn can be attributed to the winemakers and their own proclivities. “I think it’s because winemakers are making a concerted effort to become better farmers,” says Sonoma County-based sommelier Christopher Sawyer. “They’re really trying to optimize the grapes and not over-accentuate the sugar, while paying more attention to acidity by taking more time per vineyard, per site, to maximize the fruit quality.”
Though the lower-alcohol wine trend is already in motion, Wallace says it “really won’t be obvious for another 5 years. Things progress really slow in my trade.”
Orson Welles might agree.