Science

After a fiery 2017, West Coast winemakers are adapting to a changing climate

It isn’t obvious, standing by the stainless steel tanks where wines are supposed to ferment, that Tom Eddy’s winery was at the epicenter of the Tubbs Fire, which last year burned about 20 miles from north of Calistoga in Napa Valley to Santa Rosa. In fact, on October 8th last year, the winery was at the heart of the conflagration. But even though the charred meadow below has recovered, and the tanks appear unharmed, there was a casualty: the wine. The juice the tanks held had been tainted by smoke.

Eddy lost 80 percent of his 2017 wine, representing what he says was a $2.5 million loss. “The only reason I can still function is that I don’t have that much work to do,” the 66-year-old winemaker wryly tells me. Now, left without a harvest, Eddy walks me into his cave, in which oak barrels sit, each holding the previous three vintages.

He pulls his 2015 cabernet sauvignon, which was trapped in barrels during the fire and bottled five months later. The wine, called Elodian, will be released next year at $60 a bottle. Eddy insists that I’ll find no fire smoke in the aroma or flavor.

When I taste the wine later, I do so slowly over the course of hours, to see if the smoke taint shows. The only suggestion of smoke came at the top of the palate, apparently from the barrels in which the wine sat for 17 months. (Coopers char barrels over open flames during the construction process.)

It’s possible most consumers will have no clue that Eddy’s wine had come from a source that was inundated with smoke from the fire. That’s precisely what the wine industry wants.

When the record-breaking fires swept California last year, there were only a few grapes left out — 90 percent had been harvested already. The wine industry is anxious to tell you that the wine was mostly unaffected. I talked to more than a dozen sources for this article, and all of them were afraid that the ‘17 vintage would be forever tainted as the Fire-Damaged Year.

But fires are more frequent than they used to be, which is why wineries are trying to identify what the industry calls smoke taint — a specific flavor profile that comes from fire exposure — and remove it, as quickly as they can.


Wildfires have always threatened world wine regions. In Australia, Chile, Portugal, Spain, Washington state, and California, fires have for decades damaged wine, resulting in billions of dollars lost. But the fires are only getting more frequent and more serious as climate change warms and dries certain wine-growing regions.

It matters when in the year fires happen, too. For instance, in the summer of 2008, California experienced wildfires for weeks. The timing meant that the fire’s detritus was absorbed by the vines, before budbreak; and will therefore carry molecules into the skins. When the fruit actually begins to appear, smoke penetrates the skins of the grapes, compromising the juice. In 2017, the fires occurred over a shorter period of time, and later in the season when most of the grapes were picked; whatever accumulation of smoke there was, entered through the grapes. More drought means more fire and less certainty about when in the growing season it will be.

Even the places where wines can be grown have begun to shift. For instance, wine grapes are being grown in England and Sweden — two areas that heretofore, have not planted vinifera (grapes specially cultivated for making wine). Grapes that are currently being grown in known wine regions might have to be planted elsewhere due to climate change. More heat — and more drought — during the growing season poses a challenge to winemakers, says David Graves of Saintsbury winery in Napa Valley.

Cool climate varieties such as chardonnay and Pinot Noir, the grapes that make French Champagne, are also being harvested in southern England as a hedge against climate change. The Champagne region may become too warm to grow top-quality grapes, according reporting from The Atlantic and Vinepair.

The rising summertime temperatures will make business as usual impossible for wine regions, Graves says. “Some of my colleagues think they can change a few management practices but otherwise pretty much stay with business as usual,” he tells me. “I don’t think that is a wise strategy.”

Compounding the problem, New World wines generally use a narrow selection of wine grapes. So examining genetic diversity of those grapes might reveal varieties that could adapt to the future climate, Graves says. He predicts that Napa will grow a broader mix of grape varieties in the future — but figuring out how to fully deal with fire could take decades. After all, fire doesn’t just pose a risk to the wine — it threatens the people who grow it, and the places where they live.

Graves isn’t alone in sounding the alarm. When Harry Peterson-Nedry, an Oregon winemaker who owns Ribbon Ridge Winery, started growing grapes in 1980, the region was ideal for cool weather grapes like Pinot Noir and riesling. Now his winery is almost warm enough for cabernet sauvignon.

Nedry, who is a chemist as well as a winemaker, has been tracking climate records for decades. Temperatures in the Willamette Valley’s McMinnville, the commercial center for that wine region, were 17 percent higher during the growing seasons of 1997 to 2007 than they were from 1961 to 1990. “It seems to really have ramped up in the last five years,” he told McClatchy DC last year. “If we see this for another five years, we will really be questioning what is going on.”

A decade ago, Greg Jones, the director of wine education at Linfield College in McMinnville, was already talking about the dangers of climate change. He predicted then that we’re going to experience warmer and longer growing seasons, longer dormant periods and altered ripening profiles. Then, he said that he was no longer on the fence about climate change — the climate in wine-growing regions would be different in the future.

“Climates have changed actually more rapidly than anticipated,” he says now. The climate is both more variable and warmer — bad news for specialty crops like wine grapes that are very sensitive to the weather.

Not only is it getting warmer in Oregon, there’s more temperature variation, Jones says. “Grape growers can anticipate that to some degree; and perhaps they can adapt to it,” he says. But if drought, heavy rainfall, or frost start to be less predictable, it will be even harder for growers to adapt.

What’s a winemaker to do? Does it make sense to create a bigger canopy to shelter the fruit, or plant on a different, cooler slope? As it happens, there are some models.

Some growers in southern Sweden, parts of Canada, and Michigan are planting wine grapes that can cope with variable temperatures, and that resist smoke, Jones says. In Oregon, California, and Washington, for instance, less than a century ago, the climate was “marginal” for grape production, Jones says. In those days, because of climate difference, only two or three vintages were considered good. The climate now is becoming more suitable for Pinot Noir, pinot gris, and Müller-Thurgau grapes in places such as Washington’s Puget Sound. “That region is in the same place the Willamette Valley was in the ‘70 and ‘80s,” Jones says.

But wine growers aren’t the only ones on the problem. Scientists in Australia and in the US are frantically analyzing grapes to determine if certain varieties can be grown elsewhere, in places that are less susceptible to wildfires. They’re also looking for grapes that are less likely to be ruined by smoke, and to sort out what to do with grapes that have been exposed to fire, leading to what those in the industry call smoke taint.

Wine has always been chemically sophisticated, a point illustrated by a 170-year-old bottle of Champagne discovered in a shipwreck in the Baltic Sea. The find, reported in a 2015 paper in the Proceedings of the National Academy of Sciences, shows how much can occur in sealed 750-mL microlaboratories. When modern scientists analyzed the bottles, the results revealed “unexpected chemical characteristics in terms of small ion, sugar, and acid contents as well as markers of barrel aging.”

The earliest winemakers didn’t have our sophisticated knowledge of the microbes that drive fermentation, though. It wasn’t until Antonie van Leeuwenhoek first observed cells in 1680 that “modern” chemistry took hold. But even before we knew exactly how it happened, yeast and fermentation have been the cornerstones of winemaking for millennia.


The chemistry of smoke taint was kickstarted in 2008, after a series of near-annual Australian bushfires began proliferating, destroying vineyards, and causing smoke tainted grapes. That fire damage was the catalyst that prompted the Australian wine industry to begin extensive testing. At first, scientists had identified only one compound that contributed to smoke taint: guaiacol, which affects taste and color. Now, at least four others that contribute to the burnt odors in wine have been identified. But only recently have scientists begun to realize those molecules may not predict whether the grapes will make smoky wines.

So nervous Californian winemakers — worried about the possibility of smoke taint — can now take samples to the American wine industry’s most important lab, ETS Laboratories. The unremarkable two-story office building in Napa Valley’s St. Helena, is devoted exclusively to analyzing grapes. When I visit, cars pull up and people emerge carrying small boxes filled with test-tube samples of wine.

Inside, Gordon Burns and his crew of about 25 scientists and technicians hunch over their instruments. At first, Burns is reluctant to speak about the fires — too much has been written about it, he says, and he doesn’t want to hurt the industry by associating all 2017 wine with fire. Three media outlets had called him just that day.

For the last seven months, most of ETS’s work has been telling panicky clients whether their specimens show the telltale signs of smoke taint. There are at least a half-dozen compounds that stick to sugars, and their presence indicates smoke-tainted aromas and flavors.

Burns’ lab uses more than a half-dozen gas chromatography and mass spectrometry machines to detect trace amounts of identifiable compounds that might indicate fire-smoke markers. ETS claims it can measure compounds to one part per billion. The lab was running 24 hours a day after last year’s California fires. In the two or three days after the fire, there was no power at the lab, forcing ETS to use its generators; it was possible that smoke might have infiltrated his equipment. After testing, ETS determined little or no smoke was detected in the instruments — and so the lab got to work.

Burns’ lab isn’t trying to figure out whether the wines will smell or taste different, he tells me repeatedly. Instead, the goal of ETS is to show which varieties of wine are most susceptible to smoke taint.


But what to do with the grapes that have already been tainted by smoke? Vintners have a few choices: discard them or sell them on the bulk market, where likely they’ll be blended into other wine.

It may be possible to remove some of the offending flavors of smoke taint, according to Bob Kreisher, president of Mavrik North America (MNA) wine processing in Santa Rosa, California. His company filters wine, using a membrane (the type is proprietary) to separate the known smoky compounds from the rest of the wine — which, ideally, spares the aromas and flavor of the wine in question. “Fortunately, nobody has determined that they have to get rid of a single lot we’ve treated,” he says.

Commercial labs are not the only entities working to understand — and, ideally, mitigate — smoke taint. Universities such as UC Davis, Washington State, and Oregon State are working together on the problem, too.

For instance, there’s Davis’ Anita Oberholster, whose focus is developing analytical methods to diagnose smoke taint. She’s gotten grapes from growers that were affected by last year’s fires. “The main reason why they offered me the grapes is they were not going to pick them otherwise,” she says. “All my grapes come from vineyards that were pretty close to the fires and had several days of heavy fresh smoke exposure.” Oberholster’s team has tasted all the wines from those grapes, and though the degree of smokiness varies, all of them were affected.

Most solutions for removing smoke taint rely on one form or another of filtration. Some ways to reduce smoke taint rely on enzymes to remove fire-related solids from the wine. Another technique involves passing wine through a tight filter, removing the compounds known to cause smoke taint by dissolving and removing them. A third method, the process which MNA and others use, involves certain kinds of membranes — but because that technology is proprietary, labs tend to be secretive about how it’s done. With any of these methods, there’s a risk that natural aromas and flavors could be removed with the smoke taint, though.

As the climate changes, extreme weather events will happen more often. Joe Cafaro, a winemaker and grower in the eastern hills of Napa Valley, lost half his vineyard in October’s fires. “This is our new normal,” he says.

When all else fails, there’s always marketing. Take, for instance, France’s solution: a yeast called Brettanomyces, which is found in dirty cellars, sometimes remains in the Burgundy region’s wine, causing a distinctly barnyard aroma. But through creative marketing, the region has associated that aroma with high-quality wines. And now, Burgundy lovers insist they love the earthy aroma in their Pinot Noirs. With a little creative force, smoke could become a positive for certain wine regions — reinforcing the wine’s authenticity.

Another option is cutesy brand names. When the now-defunct Carmenet Winery’s vineyards in Sonoma County were damaged by a fire in 1997, the winemaker debuted Dynamite Red and a white it called Burning Leaf. Those brands, created by wine industry veteran Michael Richmond, sold a lot of wine; 8–10,000 cases per year, which eclipsed sales of the parent brand. Or after the New Zealand Boxing Day fire of 2000, the Fire Road brand was created by folks who fought the blaze in Fireroad.

Once, Tom Eddy, the winemaker from Calistoga, set a wine barrel on fire, quickly put it out, poured wine into it, and tightly sealed the bung – just to see how the wine would fare. It was as smoky as one can imagine. He raised the price $20.

This year, he can’t do much — the tanks that overlook the meadow where the fire raged are empty, and most of his 2017 crop was wiped out. But the scale of the fires means that the market may soon be clogged with newly named, smokier wine. And that means he won’t be able to add a $20 surcharge for smoke.

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