Wine Becomes More Like Whisky as Alcohol Content Gets High

(ScientificAmerican) - It's not your imagination. Wine really has gotten boozier.

In the past two decades the maximum alcohol content of wine has crept up from about 13 percent to, in some cases, northward of 17 percent, a side effect of the growing popularity of wines with richer fruit flavor. The intoxication inflation has gotten so bad that wine scientists have begun to bioprospect for wild yeasts that turn a smaller quantity of the sugar in grape juice into alcohol during fermentation than does the yeast Saccharomyces cerevisiae—humanity’s partner in inebriation for thousands of years—but which can still produce a fine, finished wine.

A team of scientists from Australia and Spain now has apparently accomplished this enological first, having identified a new, wild yeast that reduced alcohol concentrations in Shiraz wine by 1.6 percent. The yeast may even improve or at least diversify the quality of the wines it helps make. Although many people enjoy stiffer wines, others are concerned by the effect of so much alcohol on these wines’ quality, not to mention imbibers’ health, and would welcome an option that provides the flavors associated with high-alcohol wines without the accompanying effects on blood–alcohol content.

The recent surge in wine's punch is largely a result, scientists say, of a fashion for deeply colored wines with fewer “green” qualities and more bright, ripe, fruity flavors. As New World wines in this style have drawn more fans, even European winemakers accustomed to making lower-alcohol wines in less ripe styles are beginning to follow suit. But producing wines with those flavors means letting grapes hang longer on the vine, and with longer hang times comes bigger sugar. The more sugar the wine yeast S. cerevisiae has to work with, the more alcohol it will make.