It’s not just burns and evacuation that winegrowers worry about. Smoke is another disrupter. It causes an insidious defect: an off-taste or smell that may not reveal itself until the wine has been bottled.
The financial losses from smoke taint are substantial, and they’re why the industry is closely watching lawsuits filed in 2019 by two Sonoma-based wineries, Kunde Family and Vintage Wine Estates. Their insurance carriers refused to cover smoke damage estimated at $7 million and $12 million, respectively, from the 2017 fires. Meanwhile, the threat of future fires has also sent grapegrowers’ insurance rates soaring with increases as high as 200 to 300 percent. Some carriers have dropped coverage altogether.
“So if you cannot afford insurance and you have a loss, there aren’t many businesses that can weather that,” says Steve Tamburelli ’87, a former CEO at Stags’ Leap Winery and Clos du Val, now co-owner of Vinitas Wine Group consulting firm.
Jaeger, the Cakebread Cellars CEO, says wildfires are “a critical variable to deal with,” so the industry is focused on coming up with solutions to address potential damage like smoke taint. “We believe that the frequency of fires is increasing,” he says, “so we’d better have a good understanding about the impact of smoke and its effect on vineyards and our winemaking production.” While specialists are researching ways to correct for smoke taint, there is still no perfect solution.
Even in the absence of the infernos, though, changing climate trends are already impacting the wine business.
Vineyards blanketed in morning fog. Cool temperatures. These are the conditions that helped make southern Napa County, Napa—ideal for growing chardonnay grapes.
Over the years, though, the temperature has climbed— about 1.3 degrees Celsius on average since the 1800s, according to a statistical analysis by The Washington Post that relied on data from NASA and the National Oceanic and Atmospheric Administration.
The same analysis shows average temperatures have increased 2.3 degrees Celsius in Santa Barbara County. That’s above the target for limiting the average increase of global temperature set forth in the Paris Climate Accords of 2016.
So what does heat do to wine?
It disrupts the precarious combination of soil, water, and weather that makes up a wine’s terroir—the environment-driven flavor and mouthfeel. The balance is so delicate that, for example, grapes are often grown on one side of a hill but not the other to best take advantage of coastal fog.
When it’s hotter, grapes ripen more quickly, intensifying the fruit’s natural sugars and changing the flavor. Think of the difference between sweeter white zinfandels or muscats compared with drier cabernet sauvignons or syrahs.
When he was just starting out in 1980, Paul Dolan ’72, a fourth-generation winemaker who spent almost three decades at Fetzer Wines, says he was “super happy” producing a cabernet at 23 or 24 percent sugar, and a 13.8 percent alcohol content. Today, Dolan runs Truett-Hurst in Healdsburg and says because of more “heat degree days”— how much heat a grape vine is exposed to during a growing season—he is struggling to keep the sugar level below 30, and alcohol content to 16 percent.
As it happens, these riper grapes have translated into denser wines that are popular. But as the years go by and temperatures continue to climb, Dolan says already hot areas like the Central Valley—where more than 107,000 acres of wine grapes currently grow—could struggle.
Experts say the Central Valley will hit more boiling temperatures more frequently because of human-caused climate change. A 2019 report by the Union of Concerned Scientists forecasts the region will experience an average of more than 25 days per year with a heat index above 105 degrees Fahrenheit. Given that the Central Valley produces 40 percent of the nation’s fruits and nuts, that heat will have a profound impact on agricultural workers and California-grown produce beyond grapes for wine.