Bring up the topic of climate change to vinegrower Steve Matthiasson and you’ll find he is prone to strong opinions. Ask him “Is Napa is getting too hot for Cabernet Sauvignon?” and he’ll tell you “That’s ridiculous,” his voice rising. “Complete horseshit.” 

“The Napa Valley,” he goes on, “is a climate-diverse place. Carneros has two-thirds the heat accumulation as Calistoga, and Carneros is still thought of as too cool for Cabernet. Even Oak Knoll [just north of Carneros] is too cool. If you’re Larkmead, it’s a different situation than if you’re Sinsky.” Blanket statements, in other words, aren’t of much use to a grower and winemaker whose attention to detail is particular, granular, and even subterranean, as we shall see.

With his partner Garrett Buckland, Matthiasson founded Premiere Viticulture Service in Napa in 2002. Together they manage vineyards up and down the Valley (current and past clients include Spottswoode, Duckhorn, Stags’ Leap Wine Cellars, Dalle Valle, and Eisele Vineyards). Most hire Matthiasson to convert conventional farming practices to organic. It’s made Premiere Vit, as it’s known, one of the most successful organic consultants in California. And Matthiasson has been staring into the hot maw of global warming for the entirety of his thirty-year career, taking its measure, countering its effects, adding to his toolbox. So far he hasn’t blinked.

That’s not to say that climate change hasn’t thrown some serious shit in his path: years of drought, heat spikes, cold snaps, untimely atmospheric rivers, off-season lightning strikes, fires and firelines advancing to within yards of his home vineyard, his home, his winery. This is not a person who’s disbelieving of climate change. But he’s a vineyard manager, and managing does not mean sitting idly by and watching the Valley air-fry to a crisp. It means actively, preemptively, taking steps to mitigate its effects. And it means helping the vines manage their own defenses against heat, against drought, against cataclysm.

Adaptation is key, he’ll tell you. He takes issue with the doomsayers, those who assume that climate change will be inherently drastic for the Valley. He will tell you that the challenges brought on by global warming, at least for now, are manageable. “Organics, regenerative farming, it’s all about encouraging the vine to rely on its own microbiome,” he says. “A balanced vine in healthy soil can acclimate. It can handle heat.”

Moreover—and this is particularly good news for the region—he contends that few varieties are more adaptable than Cabernet Sauvignon. “I work with a lot of varieties,” he says. “I haven’t found anything more heat tolerant than Cab. “It can handle crazy climate swings, dry weather, north winds, heat, drought. It can roll with the punches. It’s rugged, man.”

Matthiasson’s own wines bear this out. With his wife Jill, Matthiasson founded their eponymous winery in 2003—it’s an NWR favorite—applying lessons learned in Napa vineyards with a restrained hand in the cellar. The results are some of the Valley’s most graceful bottlings; Cabernets, blends, and other varietal packages known for lifted aromatics, vibrant fruit, and mouthwatering tension. Wineries like Matthiasson’s–wineries like Corison, Spottswoode, Dunn, Frog’s Leap, Stony Hill, Smith Madrone, Ashes and Diamonds, and Philip Togni–might still be in the minority, but they’ve  proven that such wines are achievable in the Napa Valley, even in the age of global warming.

“I’ve got PTSD trying to convince the wine world that it’s possible to make a delicate red wine in the Napa Valley,” he says. “I’d have thought that between my wines, Cathy Corison’s, others who’ve embraced the pursuit of balance thing, that we were beginning to win that fight. We’ve proven it’s possible: our alcohols have gone down over the last decade. If you’re not making wines below 14% alcohol,” he continues, “it’s because you don’t want to.“

“And now you want to blame climate change? Fuck that. Taste the wines. We don’t remove anything. The only thing we add is SO2. You can say what you like about these wines, but you can’t say they’re overripe.” 

It begins in the vineyard, of course. Matthiasson and Buckland have myriad practices to slow down the ripening progress and mitigate the effects of heat, drought, and seasonal extremes. 

For decades, the paradigm was the reverse; growers aimed their viticultural practices so that the fruit could attain maximum ripeness. “All of your pruning, trellising, shade, row orientation, all of it was designed to get the fruit as ripe as possible,” says Matthiasson. But he was never happy with the fruit quality. “What does heat do to Cab?” he asks. “It makes it flabby basically.  Dull flavors, flabby textures, soft, lacking energy.”

After 2010, the paradigm began to shift. Robert Parker’s influence receded, while the climate became more extreme, leading to not just warmer weather, but weirder weather. After a severe drought in 2013, the mindset shifted to vine resilience. “The idea was to protect the fruit, and keep berry temperatures down,” explains Matthiasson. “You don’t want to warm the fruit up. When you do that you lose acid, lose flavors, anthocyans. Exposed fruit gets sunburn.” 

In a typical Premiere Vit vineyard, the fruit is shaded by the canopy. In some vineyards, the team even resorts to shade cloth, enveloping the fruit zone. “If you keep fruit shaded you don’t get that heaviness that comes with sun exposure,” says Matthiasson. “Most of our clients are looking for ripeness at lower brix—that’s one of the reasons they work with us. We want to stave off sugar development, but speed up phenolic development so we can get fruit off the vine more quickly.”

When planting new vineyards, Premiere Vit have begun to orient the rows thirty-five degrees off true north—again, to reduce sun exposure, and allow the vinerows to shade the fruit. “In August, at 3:30 PM, at our latitude, the sun is shining right over the vines, and so the fruit is protected by the leaves,” explains Matthiasson. “There’s more morning sun, but the heat load is balanced.” This being Napa, they have other nice, tech-forward toys to help keep tabs on the heat. Recently, in a Rutherford vineyard, Buckland showed me an imaging app which measured a grape’s temperature just by scanning it with his phone’s camera.

But in the face of environmental extremes, much of a vine’s resilience occurs below ground. According to Matthiasson, organics is largely about making the vine dependent on soil for its nutrition, disease resistance, overall hardiness, instead of what cynics call ‘fertigation.’ Through compost, teas, and other judicious  use of inputs, he seeks to nurture a biochemical universe of microbial organisms to for the vine to interact with. A vineyard manager manages a microbiome, too.

“A plant with plenty of fertilizer becomes less dependent on its microbiome,” he explains. “Nutrition from its microbiome isn’t used.” In a working system, according to Matthiasson, microbes, rhizomes, and bacteria all feed off the plant’s carbohydrates, from the root. They need the same nutrients as the plant does: phosphorous, potassium, nitrogen. “When a plant works for its own nutrition,” says Matthiasson, “it has to grow more roots, it has to make friends with microbes to use their organic acids. The microbes in turn send signal molecules that help with its immune system, which improves the plant’s health. You get better phenolics, and less water stress.” 

Simply put, that symbiosis, where the soil is dependent on the plant which is dependent on the soil, leads to more resilience, and better flavors. “The idea is to feed the soil, not the plant,” says Matthiasson. 

The day may come when climate change disrupts this symbiosis irrevocably in the Napa Valley, at least as far as Cabernet is concerned. Steve Matthiasson, at least, is looking to put off that day as long as he can. For now, it seems to be working.