06 Mar 2014 Wine’s surging alcohol punch: the good, the bad, the remedies
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 flavours 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 coloured wines with fewer “green” qualities and more bright, ripe, fruity flavours. 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 flavours 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.
According to Matt Stamp, master sommelier and education director at the Guild of Sommeliers, the trend has its origins in wine expert Robert Parker’s lauding of the 1982 Bordeaux vintage, but other critics and high-profile wine magazines have followed suit in giving high praise to full-bodied, concentrated, high-alcohol wines.
“Those are the wines that are making 100-point scores,” he says.
More alcohol can also counterproductively dampen wine’s characteristic bouquet. Most of the volatile components of wine—the chemicals responsible for the many fruity, herbaceous or earthy aromas—become more reluctant to diffuse from liquid to air in higher-alcohol wine.
Stiffer wines may also incur higher taxes. And then, of course, there are alcohol’s well-documented effects on waistlines, health and well-being.
“You want to be able to have a glass of wine with lunch or dinner and be able to still function afterwards,” says James Kennedy, chair of the Department of Viticulture and Enology at California State University, Fresno, and president of the American Society for Enology and Viticulture, “and I think with these creeping alcohol concentrations people are concerned generally about ‘Are we drinking too much alcohol as a society?’ and ‘Should we perhaps try to tone it down a little bit?’”
Stamp agrees, and sees other problems. “Wines that are 15 percent alcohol and more are not exactly wines you can make it through two or three bottles of over the course of a meal with friends,” he says. “They’re wines you might want to drink a glass of, but they’re not wines that respond well to a lot of the more delicate styles of food we see in modern restaurants.”
Sommeliers, he says, have begun pushing consumers to consider more moderate-alcohol wines with higher acidity and more delicate character that pair better with many foods, he says, and some have embraced the suggestions. But for those who prefer big, bold wines and would still like to be able to drive home, science may have a solution.
Finding ways to produce weaker dry wines from riper grapes has proved a challenge. Although there are more than 100 varieties of winemaking yeast—all S. cerevisiae—each of them produces virtually the same amount of alcohol given the same amount of sugar. Winemakers could stop fermentation early to reduce alcohol, but the unprocessed sugar would remain and make producing dry wine impossible.
Winemakers and scientists have already tried a variety of approaches to promote or preserve ripe flavours while reducing alcohol: clipping the leaves covering grape clusters, for instance, or changing irrigation practices or artificially removing alcohol from finished wine, all of which can affect flavour. The success of these strategies has been limited.
Alan Bakalinsky, associate professor of food science and technology at Oregon State University, who’s long studied wine yeast, says that winemakers have tried to tinker with S. cerevisiae for years to get it to reduce it’s alcohol production efficiency. But doing so can alter the yeast’s winemaking abilities or cripple it, and certain methods of doing it may involve genetic modification that consumers may not like. Finding a wild yeast that already has the desired suite of traits would be a simple and elegant shortcut, he says……