Forced to start picking grapes much earlier than normal because of torrid temperatures, winemakers across France are worrying that grape quality will suffer from the climate-induced stress.
The exceptionally dry conditions spread from the rugged hills of Herault along the Mediterranean, where picking is already underway, to the normally verdant Alsace in the northeast.
"We were all a bit surprised, they began maturing very rapidly these past few days," said Francois Capdellayre, president of the Dom Brial cooperative in Baixas, outside Perpignan.
He said the shears came out on August 3 for the region's typical muscat grapes, followed by chardonnay and grenache blanc.
"In more than 30 years I've never started my harvests on August 9," saidJerome Despey, a vineyard owner in the Herault department.
- Stressed out -
Like other farmers, French winegrowers have been grappling for years with increasingly common extreme weather including spring freezes, devastating hailstorms and unseasonably heavy rains.
Only 10 percent of France's winegrowing parcels use artificial irrigation systems, which can be difficult or prohibitively expensive to install.
And while grape vines are more hardy than many other crops, with roots that descend deep into the ground over years of growth, even they can withstand only so much.
When water is scarce, the vines suffer "hydric stress" and protect themselves by shedding leaves and no longer providing nutrients to grapes, stunting their growth.
In Alsace, "we haven't had a drop of rain in two months," said Gilles Ehrhart, president of the AVA growers' association.
"We're going to have a very, very small harvest" after picking begins around August 26, he said.
And when temperatures surpass 38 degrees Celsius (100 Fahrenheit), "the grape burns -- it dries up, loses volume and quality suffers" because the resulting alcohol content "is too high for consumers," said Pierre Champetier, president of the Protected Geographical Indication (PGI) for the Ardeche region south of Lyon.
Champetier began harvesting Monday, when "40 years ago, we started around September 20," he said.
Now he worries that global warming will make such premature harvests "normal."
Some winemakers are still holding off in hopes of rain in coming weeks, such as red grape producers in Herault, where harvests should begin as usual in early September.