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Grapes exposed to smoke during the growing season can impart an unpleasant, smoky flavor to wines, potentially wiping out a year’s work in a community that’s still reeling from wildfires.

October 01, 2015

The people of Lake County, California, have already weathered a devastating fall, facing fires that ravaged 75,000 acres, destroying businesses and forcing residents from their land. Thankfully, the fires are now largely contained, and the county is beginning to rebuild, but there’s still lingering concern about another potential problem: the loss or degradation of this year’s harvest due to smoke taint.

Lake County lies just west of Napa, separated by the Mayacamas Mountains. Though it gets infinitely less attention than its posh, famous neighbor, Lake County is an integral part of northern California’s wine world—the cultural and economic heart of the region. (Just Napa’s wine sector alone employed 46,000 people as of 2012, and was thought to have more than a $25 billion impact on the state’s economy.) Not only do countless Lake County residents work in the industry, but the county is also home to dozens of wineries, and its vineyards supply grapes to many Napa and Sonoma producers. Damage sustained by any one of these counties reverberates throughout the area.

This past month, all local winemakers have been keeping an eye on the fires. “When the fire blew up, it looked like an atomic bomb went off,” said Matt Crafton, the winemaker for award-winning Napa winery Chateau Montelena, which is relatively close to the Lake County border, of the first major fire day. “We knew it was close and knew it was big.”

So far, Crafton says, constant westerly winds have protected Napa from the fires. But many of Montelena’s workers live in Lake County and have been displaced. “We’re really concerned for our people,” Crafton says. The winery has taken them in for their own safety, and many are sleeping onsite while the fires rage on.

Northern California has been through this before. In 2008, Mendocino, which borders Sonoma and Lake counties, was hit hard. “There were over 100 fires for five weeks, and areas were blanketed in smoke,” says Glenn McGourty, a viticulture and plant science advisor at the University of California in Ukiah. “It affected Sonoma, too. There were smoke flavors in the fruit. Some we could fix, and some we couldn’t.”

This smoky flavor, which results from grapes in the vineyard being exposed to smoke, is called smoke taint, and it could wipe out a year’s worth of work.

The 2008 fires occurred in July, which was even worse for the industry, since the grape skins are more apt to absorb smoke earlier in the season. When making white wines, McGourty explains, the threat of smoke taint is less of an issue than with red wines since there’s little or no skin contact for whites during the winemaking process. But with red wines, it’s a different story: winemakers can try using techniques such as ultrafiltration and reverse osmosis to mitigate the smoke’s effects, but the result is often far from ideal.

It’s an evolving science, and for all the wrong reasons, since fires in the drought-ridden state are getting worse. “No one even knew there was a line that could be crossed until about ten years ago,” says Jim Gordon, the editor of the industry publication Wines & Vines, of the sorts of challenges California winemakers now face.

 “2008 was a vintage none of us want to remember,” says David Green, winery president of Lake County’s Brassfield Estate, makers of an excellent Sauvignon Blanc and other wines. In part because of smoke damage during that annus horribilis, Brassfield didn’t make wine under its own label and declassified its grapes (meaning the company sold them off for bulk wine, at a loss).

During that difficult time, a few lessons were learned about how to deal with possible smoke effects. “New oak is not your friend,” says Green, referring to aging reds in barrels made of new oak, opposed to older, milder oak. “It exacerbates the ashtray taste.”

In the 2008 season, quite a few wines were released into the market that had smoke taint, though as McGourty points out, “Not everyone can taste it. Winemakers are super sensitive. A lot of people wouldn’t notice, frankly.”

McGourty hasn’t been over to Lake County since the current fires because of road closings, but the most recent reports from wineries there are somewhat encouraging. The local associations of wineries and grape-growers recently issued a joint statement saying that they hadn’t seen elevated levels of guaiacol and 4-methylguaiacol, two organic compounds that correlate to smoke flavors—at least not yet.

Hopefully this year’s crops will emerge unscathed. But, unfortunately, without a solution to the drought in sight, the threat of smoke taint may become a lasting part of the parched state’s new reality.

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