Photo: Flickr/David Huang
Over the past several decades, viticulturists find themselves increasingly facing a problem you might not expect: Their wines are becoming too alcoholic.
Boozy wine isn’t necessarily a preferred characteristic for connoisseurs: High alcohol content can “compromise wine quality, including increasing the perception of hotness, body and viscosity and, to a lesser extent, sweetness and acidity,” according to researchers at the Australian Wine Research Institute.
“It can lead to a decrease in aroma and flavor intensity,” they say, which is not a good look if you’re trying to pick out notes of licorice or a hint of lemon at your wine tasting.
Like many other things in agriculture, the rising alcoholic content of wine can potentially be blamed on climate change. Grapes grown in warm climates, such as Australia, generally have higher sugar concentrations, which leads to wine with higher alcoholic content. It’s one of the reasons previous research has suggested that, eventually, large regions of France and Italy might no longer be suitable for wine grape production and that the best wines in the industry might eventually come from places such as Oregon and Montana.
In the past few years, the average alcoholic content of wine has increased from roughly 12 percent to more than 15 percent, a modest change but one that can deeply change the flavor profiles of some wines. In Bordeaux, for example, one vineyard owner said rising alcoholic content threatens the industry.
“The Merlot has got so high in alcohol that we run the risk of losing the Bordeaux style,” Didier Cuvelier, owner of Chateau Leoville Poyferre told Decanter magazine in 2011.
Rising alcohol content can also cause economic problems in countries that begin to classify drinks above 15 percent ABV as hard alcohol and thus tax it more heavily.
There is, however, a way of bringing down alcoholic content: use different types of yeast. To try to do that, researchers made wine with more than 50 different types of yeast in hopes of finding one that converts sugar into products other than ethanol without severely changing the flavor profile.
It kind of worked: In a study published in Applied and Environmental Microbiology, the Australian team added a combination of two types of yeast, Metschnikowia pulcherrima and Saccharomyces cerivisiae to unfinished wine mixes, which successfully reduced the alcoholic content in a shiraz from 15 percent to 13.4 percent without changing its flavor. That’s not a huge change, but it might be enough for stave off the changes that global warming are quickly bringing to the industry for at least a few more years.
It’s not quite that simple, however: While the process works in several types of grapes, when tried on a Chardonnay, the alternative yeasts created side products that reduced the quality of the wine. But, unless warming can be stopped or slowed, continued band-aid solutions might be the best that some vineyards can hope for.