ALPINE (OREGON), USA: The West Coast of the United States, known for producing over 90% of the nation’s wine, faces a perilous conundrum—the nexus of wine production and wildfires. The devastating events of 2020 showcased the destructive impact of this combustible combination on the industry. In response, scientists are racing against time to mitigate these threats and protect the future of American winemaking.
When you savour a well-crafted wine, you might discern notes of oak or red fruit. However, wines made from grapes exposed to wildfire smoke can be marred by an unpalatable ashy taste, reminiscent of an ashtray poured into your glass.
Researchers from three prominent West Coast universities are joining forces to combat this issue. Their collaborative efforts encompass developing innovative spray coatings to shield grapes, identifying the elusive compounds responsible for the unpleasant taste, and deploying smoke sensors in vineyards to gain a deeper understanding of smoke behaviour. Generous funding from the U.S. government supports these vital research endeavours.
Wineries are also taking proactive measures to safeguard their products and reputations. The escalating risk to America’s top wine-producing regions, exacerbated by climate change-induced drought and overgrown forests turning into tinderboxes, demands immediate attention and innovative solutions.
According to the U.S. Department of Agriculture, grapes constitute the highest-value crop in the nation, with a vast expanse of grape-bearing land—96% of which is situated on the West Coast, amounting to a million acres (405,000 hectares).
Winemakers worldwide are adapting to the challenges of climate change by relocating their vineyards to cooler zones and cultivating varieties resilient to drought and heat. Nevertheless, wildfires pose an imminent and additional threat, prompting scientists from Oregon State University, Washington State University, and the University of California, Davis, to intensify their efforts in finding solutions.
What’s at stake is the ability to continue making wine in areas where smoke exposures might be more common, cautions Tom Collins, a wine scientist at Washington State University.
Researcher Cole Cerrato from Oregon State University conducted experiments in their vineyard, simulating smoke exposure. Their findings revealed sulfur-containing compounds called thiophenols in the smoke-impacted wine, contributing to the ashy flavour, along with “volatile phenols,” previously identified by Australian researchers over a decade ago. Thiophenols, undetectable in wildfire smoke, manifest in smoke-impacted wine. Understanding their presence and finding ways to eliminate them is a pressing goal for the researchers.
Wine made with tainted grapes can be so awful that it can’t be marketed. If it does go on shelves, a winemaker’s reputation could be ruined — a risk that few are willing to take.
In 2020, record wildfires inundated the West Coast with brown smoke, prompting some California wineries to refuse grapes unless tested. However, most growers faced challenges finding laboratories to analyze their grapes due to overwhelming demand.
The economic impact on the California wine industry alone was a staggering $3.7 billion, primarily resulting from wineries forfeiting future wine sales. The losses were particularly acute in regions like Napa Valley, known for some of the highest-priced grapes and wines in the U.S.
Between 165,000 to 325,000 tons of California wine grapes were left unharvested in 2020 due to actual or perceived smoke exposure, leading to financial strain for grape growers. The difficulty in securing insurance due to fire risk is a pressing concern for many in the industry.
Winemakers are exploring various techniques to reduce smoke impact, including membrane filtration, carbon treatment, blending impacted grapes with unaffected ones, and limiting skin contact to lower the concentration of smoke flavor compounds.
Researchers at Washington State University are experimenting with spraying fine-powdered clays like kaolin or bentonite mixed with water onto wine grapes to absorb smoke-related materials. Meanwhile, Oregon State University is developing a spray-on coating to shield grapes from smoke exposure.
Additionally, extensive efforts are underway to install smoke sensors in vineyards across the West Coast. These sensors, funded in part by a substantial USDA grant, play a crucial role in measuring smoke marker compounds, aiding in the development of mitigation strategies and determining smoke exposure risks.
Greg Jones, a director of the Oregon Wine Board, applauds the scientists’ tireless efforts and expresses confidence in finding effective strategies to mitigate the impact of smoke on wine production.
I think it’s increasingly clear that we’re not likely to find a magic bullet, notes Collins. But we will find a set of strategies.
The collaborative research and proactive measures being undertaken by scientists and winemakers alike hold promise in securing the future of American winemaking amidst the escalating threat of wildfires.
