Time to savour every last drop of the good stuff.

By Mike Huyhn

Posted on October 4, 2019

Savour that last glass of pinot noir or chardonnay from your beloved French wine label because it may never taste the same again.

A recent investigation by the National Geographic outlined the effects climate change has had on the flavour of French wine and the results are evident.

When scientists and historians analysed a 700-year-long record of grape harvest dates from the town of Beaune (starting in 1354), they found that air temperatures have increased significantly to a point where in the last 30 years, grapes have been harvested almost two weeks before their historical markers.

Two weeks might not sound like much across seven centuries, but in the vineyard world it could mean the difference between achieving a perfectly balanced flavour and one that’s too sweet and alcoholic.

“We can clearly see the reaction of the grapes to the rise in temperature,” said Thomas Labbé, a historian at the University of Leipzig.

To understand this climate effect on French wine, it’s wise to understand the importance that temperature plays in creating the perfect glass of wine. According to the study, pinot noir and chardonnay grapes from the wine region of Burgundy is known for its sensitivity to the region’s climate conditions over hundreds of years.

Red wine

The winemakers in Burgundy understand every growth stage of their harvest and often look at factors such as the vines before they bud, the plant condition as they mature, and most importantly the fat, sugary, fragrant curve of a grape just as they’re ready to be turned into wine.

Miscalculate these crucial time windows and the wine could lose the subtle flavour that the region’s winemakers pride their craft on. More specifically a grape that stays on the vine for too long loses its acidity which is what gives wine the feel in the mouth. Pick it too early and the grape’s fragrant chemicals may not be fully developed to achieve the wine’s distinct flavour.

If you have really hot temperatures, you increase the sugar and decrease acidity.”

Elizabeth Wolkovich, a biologist at the University of British Columbia who studies wine and climate relationships told the nature publication: “Grape harvest date records are the longest records of phenology in Europe.”

“We have these hundreds of years of records of what the summer temp was like, and we can use them like a thermometer.”

Grape harvest dates are used to identify the temperature that the grapes have been subjected to over the growing season. If spring and summer see warmer temperatures, the grapes mature quicker and must be picked sooner. This same rule applies during colder periods of the same seasons.

Using the patterns in grape harvests derived from tree rings and the length of glaciers in the Alps, climate historians were able to figure out that a majority of central Europe experienced warmer weather during the Medieval Warm Period between 900 to 1300. The region cooled slightly between the 15th and 19th centuries during the Little Ice Age.

These temperature fluctuations were observed to be consistent over the next few hundred years until the last 30 years in which temperatures have been more extreme.

“We winemakers are on the front line to see what happens with the weather, with the climate,” said Aubert de Villaine, the co-director of the Burgundy wine producer, Domaine de la Romanée-Conti.

“The fluctuations we have today are more significant than any time before.”

Red wine

Contrary to expectations, the warmer temperatures aren’t hurting the Burgundy wine region – yet. De Villaine told National Geographic that so far his vines have survived the heat thanks to the protection provided by their location on high hills and latitudinal position.

Jean-Marc Touzard who is a wine scientist at the French National Institute for Agricultural Research believes that by 2050, prime harvest time will occur at the peak of the summer. This in effect will likely affect how French wines taste and feel as well as how strong they are.

That will almost certainly affect the way wines taste and feel, and how strong they are. Already, as temperatures worldwide have warmed, the alcohol content of wines has bumped up from about 12 per cent in the 1970s to about 14 per cent today, though that number varies from region to region.

Part of that, though, is winemaker preference, says Greg Jones, a viticulture expert and scientist at Linfield College, but part of it is because grapes are maturing faster in the heat. The more sugar they accumulate, the more of it is converted to alcohol during the winemaking process.

“If you have really hot temperatures, you increase the sugar and decrease acidity,” says Oudin. “Here, we don’t really like too heavy, sugared, ripe chardonnays—we want to keep them fresh. And that is harder with the warmer summers.”

Burgundy’s iconic pinot noirs and chardonnays are still safe, for now. But the future is much less certain for French wine.

“We’re out dealing with the soils every day, keeping it properly and caring for them and doing what we can to make our wine. But the climate, that’s one part of our wine that we can’t control. Even if we do everything else right, we can’t control that,” adds Oudin.

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