When we grab a bottle off a retail shelf, we have expectations about the wine’s smell and taste. Some Champagnes are richer and rounder than others, but all share refreshing acidity and bright, edgy, mineral, and chalk flavors that wake up taste buds. In 2019 the region’s grapes were very ripe, but because they were balanced by super-high acidity, the classic style prevailed this year.

Harvests will not always be that way.

In simple terms, soaring temperatures from global warming lower acidity in grapes and increase sugar, which yeast turns into higher alcohol during fermentation. Heat also affects trace compounds in the grapes that contribute to flavor and aroma.

Vineyards over the hills between Acqui Terme and Nizza Monferrato, Piedmont, Italy.

Gaia Gaja, whose family owns an eponymous winery in Italy’s Piedmont, points out the most obvious taste changes: “Wines are becoming fuller-bodied, more alcoholic, and riper in flavor.” She worries that subtle notes and fleeting, delicate aromas that add so much to wine’s drinkability are at risk.

 

Warmer conditions shift red wine flavors from red fruit notes like raspberry and cherry toward black fruit tastes such as blackberry. They flatten aromas and the refreshing brightness that gives wines energy. In the Rhône Valley, summer heat is already pushing alcohol levels to 16%, about the strength of sherry. Some wine domaines—Charbonniere, for instance—plan to blend small amounts of bourboulenc and clairette, white grapes, into their reds to give more freshness to the wine in the glass.

 

Because of warming, grapes ripen more rapidly, and in many regions harvest is two weeks earlier than it once was. “With a shortened growing cycle, there’s also a risk that sugar and flavor ripening get out of sync and flavor ripening doesn’t reach its full potential,” says Kimberly Nicholas, senior lecturer at Lund University Center for Sustainability Studies in Sweden. “Finding the sweet spot, when sugar, acid, color, tannin, and flavor in the grapes are in perfect harmony, will be more and more difficult.” Especially in the face of weather extremes.

 

There’s also a plus side. Global warming has helped cooler places such as Burgundy produce more exceptional vintages, says Philippe Drouhin of Maison Joseph Drouhin, one of the region’s largest and most diverse estates. “Even if the flavor profile changes in the future, that doesn’t mean the wines won’t be as good,” he says.

-Bloomberg