The West Coast of the United States produces more than 90% of the country’s wines but the region is also prone to forest fires – a combination that spells disaster for it industry in 2020 and which scientists are struggling to neutralize.
Taste a good wine and you can smell notes of oak or red fruit. But drink a wine made from smoke-infused grapes and it will feel like someone poured the contents of an ashtray into your glass.
Wine experts from three West Coast universities are working together to tackle the threat, including developing spray coatings to protect grapes, identifying the strange compounds that create that unpleasant smell. ashy taste, and deploying sensors in the vineyards to better understand the nature of the smoke.
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The American government is funding this research with millions of dollars. Wineries are also taking steps to protect their products and brands.
The risk to America’s top wine regions — where wildfires caused billions of dollars in losses in 2020 — is rising, with climate change worsening droughts and reforested forests turning into powdery mildew. . According to the US Department of Agriculture (USDA), grapes are the most valuable crop in the United States, with approximately 405,000 hectares of productive land, 96% of which are on the West Coast.
Wine producers around the world are already adapting to climate change, mainly by moving vineyards to cooler areas and planting varieties better adapted to drought and heat. Wildfires pose an additional, more immediate risk that scientists at Oregon State University, Washington State University and the University of California, Davis are addressing.
“What’s at stake is the ability to continue making wine in areas where smoke exposure is becoming more common,” said Tom Collins, a wine scientist at Washington State University.
Researcher Cole Cerrato was recently at Oregon State University’s vineyard, nestled under wooded hills near the village of Alpine, as he turned on a fan to push smoke from a Weber grill through a dryer vent hose. Smoke billows from a row of grapes surrounded by a quasi-greenhouse made of plastic sheets held together with tape.
Previously, grapes exposed to smoke in the MacGyvered setup were turned into wine by Elizabeth Tomasino, an associate professor leading the effort at Oregon State, and her researchers.
They found sulfur-containing compounds, thiophenols, in wine affected by smoke, and determined that they contribute to the ashy taste, along with “volatile phenols,” which Australian researchers identified over a decades ago. Bushfires have long affected the Australian wine industry. In Washington State, Collins confirmed that sulfur compounds were found in wine exposed to smoke in an Oregon vineyard, but not in samples without smoke exposure.
Scientists want to discover how thiophenols, which cannot be found in fire smoke, appear in smoke-affected wine and learn how to eliminate them.
“There is still a lot of chemistry and very interesting research to start investigating new compounds,” Cerrato said. “We don’t have answers yet.”
Wine made from contaminated grapes can be too terrible to sell. If it hits the shelves, the winemaker’s reputation can be tarnished – a risk few are willing to take.
When the record forest fires of 2020 covered the West Coast in brown smoke, some wineries in California refused to accept the grapes unless they were tested. But most producers cannot find places to analyze their grapes because the laboratories are overwhelmed.
Industrial losses in California alone are $3.7 billion, according to an analysis conducted by Jon Moramarco of the consulting firm bw166 for industry groups. The losses are mainly the result of wineries having to forgo future wine sales.
“But what it really boils down to is that most of the impact is in Napa (Valley), an area of some of the most expensive grapes and most expensive wines in the US,” Moramarco said, adding that if the one ton of Cabernet Sauvignon grapes are destroyed, you will probably lose 720 bottles of wine. “When it costs $100 a bottle, it goes up quickly.”
Between 165,000 and 325,000 tons of California grapes will be left withered on the vine by 2020 due to real or perceived exposure to smoke from wildfires, said Natalie Collins, president of the California Wine Grape Growers Association.
He said he has never heard of producers leaving the business because of the effects of the fires. “But many of our members find it difficult to get insurance because of the risk of fire in their area, and if they can secure insurance, the rate is astronomically high.”
Some winemakers try techniques to reduce the effect of smoke, such as passing the wine through a membrane or treating it with carbon, but this can also rob the wine of its attractive nuances. Mixing affected grapes with other grapes is another option. Limiting skin contact by making rosé wine instead of red reduces the concentration of smoke flavor compounds.
Collins at Washington State University experimented with spraying finely powdered kaolin or bentonite, which are clays, mixed with water, on wine grapes so they would absorb the materials in the smoke. The substance is then washed before harvesting. Oregon State University has developed a spray coating.
Meanwhile, more smoke sensors have been installed in vineyards across three states, funded in part by a $7.65 million grant from the USDA.
“The instruments will be used to measure smoke tracer compounds,” said Anita Oberholster, leader of the effort at the University of California, Davis. He said such measurements are important for developing mitigation strategies and determining the risk of smoke exposure.
Greg Jones, who runs his family’s Abacela winery in southern Oregon’s Umpqua Valley and director of the Oregon Wine Board, praised the scientists’ efforts.
“This research has gone a long way in helping us try to find out: Are there ways we can get fruit from the vineyard and quickly identify if it has potential compounds that lead to wine affected by dog?” Jones said.
Collins predicted success. “I think it’s increasingly clear that we’re probably not going to find a silver bullet,” he said. “But we can find a set of strategies.”