Just a few days into this year’s harvest at the Château de Saint-Martin, a vineyard tucked into a valley in inland Provence owned by the same family since 1740, estate owner Adeline de Barry spotted one of her worst fears playing out on the vines: leaves browned at the edges surrounded by bunches of dried-out grapes, some of them irrevocably spoiled.

Putting a quick tour of the property on hold, she crouched down under the sweltering sun and ran her hands through the damaged vines. “They’re suffering,” she told me with a sigh. “This is exactly the concern.”

Vines in this condition do not make for good rosé, which is what Château de Saint-Martin is known for. “When the seeds cook, you have a smoked quality which is atrocious in wine,” de Barry says. “It’s like you’ve burned them.”

Adeline de Barry at the door of Château de Saint-Martin, in Taradeau, France.

Charred grapes have long been one of the risks of making wine in one of the sunniest regions in Europe. Growers in Provence have dealt with this challenge ever since a group of Greek settlers set down roots in present-day Marseille and introduced their vines to the fertile windswept backcountry around 600 B.C. And as de Barry noted with some relief, the vast majority of this year’s crop—which covers half of her approximately 247-acre property—appears to be in good shape.

But heat waves and prolonged droughts make scorched grapes and ruined harvests all the more likely. And as they navigate these obstacles, rosé producers are growing worried about a more subtle but potentially devastating by-product of global warming: hotter year-round temperatures that threaten to alter the very taste—and therefore identity—of their products.

It’s a cruel contradiction: as warmer temperatures push more consumers to drink rosé as a summer wine, those same temperatures threaten to transform the production methods of rosé, challenging the hallowed notion of terroir, the concept at the heart of French winemaking that refers to the distinctive environment, grapes, and modes of production that give a wine its individual essence.

At stake is the very notion of terroir.

Over the past two decades, particularly in Europe and North America, consumers have developed a taste for a certain style of rosé—dry, pale, fresh. Such wines have been perfected in the South of France, a far cry from the sugary rosés that have long been frowned upon by sommeliers. “It’s the right wine at the right place at the right time,” explains rosé expert Ben Bernheim, co-author of Rosés in Southern France.

One day all this will be rosé.

The question, however, is whether Provençal winemakers will be able to keep delivering that wine and that taste. Warmer weather and water-deprived summers threaten to lower the acidity of grapes—a key source of rosé’s signature freshness.

As regional newspaper La Provence reported last month, the area could be on track to produce denser, more full-bodied wines associated with the fiercer Mediterranean climates of North Africa, Sicily, or Greece. Fed up with the changing climate in Provence, one anonymous winemaker told the paper he was selling the family estate and moving to a more temperate plot of land. For a preview of what could be in store, look no further than France’s Languedoc region, where alcohol content in wines has shot up three or four percent since the 1980s.

Adeline de Barry also worries about the effects of warmer weather. “If it’s really, really hot this week, we’re going to lose acidity in the berries,” she told me. “For a wine to be good—and especially a rosé or a white—you need a balance between fruitiness and acidity. If you don’t have acidity, it all falls apart.”

Earlier harvests are one of the most obvious ways of adjusting to warmer weather—and like others, Château de Saint-Martin has inched forward its harvest date over the years. But to conserve that taste and to boost their crops’ resilience in general, the vineyard’s 10-person production team has experimented with a slew of new techniques, some of which are likely to make traditionalists scoff.

That starts with harvesting machines, which Château de Saint-Martin adopted a couple of decades ago. Sweeping the fields from three in the morning until just after sunrise during harvest season, the machines are meant to minimize the grapes’ exposure to temperature shifts before being processed.

Night-harvesting the grapes at the Château de Saint-Martin.

De Barry’s team also practices a form of micro-irrigation, deploying pipes to slowly trickle water and nutrients into the roots of vines. They’ve planted trees near crops for shade. And they’ve encouraged their plants to develop root hair—absorbent outgrowths from the root—allowing the plants to collect more water.

De Barry has even installed speakers that play music—a succession of single notes played on an organ, not unlike a medieval dirge—to a section of her vines for a few minutes a day. The goal is to stimulate proteins in the vines. “There are people who howl with laughter, saying this is ridiculous,” de Barry told me. “I think it’s interesting. Last year, when we suffered a lot from drought, I thought this section suffered less than the other section.”

However, the team at Château de Saint-Martin has also adopted a far more common tactic—setting aside a parcel of land to experiment with grape varieties that have proven their effectiveness in warmer climates: Xinomavro (Macedonia), Agiorgitiko (Greece), Nero d’Avola (Sicily), and Verdejo (Spain). Trials like these are now commonplace across rosé country.

Since December 2019, France’s National Institute of Origins and Quality, the agency in charge of the nation’s tightly controlled “protected designation of origin” rules, has allowed the producers of Côtes de Provence to add a couple of new grape varieties—Caladoc and Rousseli—to the traditional grapes used in rosé production—Cinsaut, Grenache, Syrah, Mourvèdre, and Tibouren. Adeline de Barry is cautiously optimistic about the new, foreign additions. “If the grape varieties have shown their benefits [in hotter regions], there’s no reason why they won’t work here,” she says.

But not everyone is so thrilled. Rosé expert Bernheim believes the decision to authorize grape varieties with no prior history in Provence undermines France’s protected-designation-of-origin system—which, by regulating different variables shaping terroirs, is meant to guarantee certain standards and an inimitable sense of place.

“It’s not really protecting the wine from climate change if you have to sacrifice the identity of the wine to do that,” he says. “We have a certain amount of protection to define a Côte de Provence or a Rhône red, and to experiment with these new varieties is to change that. At that point, what’s the point of protecting the authenticity in the first place?”

Grenache grapes are one of the staples of rosé. But can they stand the heat?

Either way, it’s too soon to know if the new foreign varieties will make for good rosé. Under the experimental phase, winemakers have to wait 10 years before deciding whether to formally request adding the new grapes to the state-regulated Côte de Provence standards.

De Barry, who is determined to pass on the family business to her children, has no qualms about updating the classification system. She says it will just be another chapter in the wine’s long history. “There have always been evolutions in taste and demand for rosé,” she says with a smile. “There’s always going to be rosé from Provence. Maybe the taste will change, but people’s tastes evolve, too.”

Cole Stangler is a Marseille-based journalist and author. His book, Paris Is Not Dead, will be released in October