UC Davis researchers investigate multiple preventative, detection and purification methods to prevent wildfire smoke taint from ruining wines
By JACLYN BOUNLUTAY — science@theaggie.org
In 2025, the California Department of Food and Agriculture valued the California grape industry at $5.21 billion. As the frequency and severity of wildfires increase, researchers at the UC Davis Department of Viticulture and Enology are investigating ways to protect this multibillion-dollar industry from the effects of smoke exposure.
Arran Rumbaugh, an assistant professor of cooperative extension in enology explained how a previous series of wildfires in 2020 economically damaged the California wine and grape industries.
“The industry lost $3.7 billion due to the wildfires and smoke exposure in vineyards,” Rumbaugh said. “Around $600 million worth of grapes were left unharvested.”
Burning plant material releases volatile phenolic compounds such as guaiacol and 4-methylguiacol, which are absorbed through grape skins. These compounds bind with sugar molecules inside the grapes to form water-soluble sugar conjugates called glycosides. During winemaking fermentation, glycosides break down and release smoky aromas, causing unpleasant, ashy flavors in wine referred to as smoke taint.
Working with a multidisciplinary team including atmospheric chemists, plant biologists and sensory scientists, Rumbaugh’s research focuses on rapidly assessing risk, linking grape chemistry to sensory outcomes in wine and developing strategies to mitigate smoke taint’s effects on wine quality.
“Growers and winemakers need tools to better understand when they are at risk, when to pick fruit or leave it unharvested, and how to manage winemaking to produce the best wine possible,” Rumbaugh said.
Her lab is working on a portable screening method that could detect smoke exposure in grapes quickly, instead of the slow and expensive lab testing that growers currently rely on. She is also collaborating with UC Davis researchers on barrier sprays that coat grape berries, testing them in controlled smoking chambers to see how well they prevent smoke compounds from entering the fruit.
Five years ago, researchers focused mainly on guaiacol. They have since identified a complex mix of smoke compounds that cause ashy flavors, some of which don’t show up until months after a wine is bottled.
Because smoke taint can slip past early detection, other UC Davis researchers are working on ways to remove it from the wine itself.
This past summer, third-year chemical engineering major Anvi Gore worked alongside chemical engineering Ph.D. candidate Connor Patton to develop a method to selectively extract smoke compounds from wine while preserving desired sensory characteristics.
Existing methods of extracting smoke compounds use materials, like activated carbon, which inadvertently remove desirable flavor compounds. Instead, the team experimented with various porous crystalline substances called zeolites to selectively extract the contaminants. Zeolites are already approved by the International Organisation of Vine and Wine for removing cork taint. The pair found promising results with Zeolite Y, a microporous material commonly used as a catalyst. After various experiments, Gore and Patton found promising results.
Gore explained her process of choosing Zeolite Y to selectively adsorb smoke compounds while preserving positive sensory characteristics.
“We [noticed] that this pore size is 0.7-0.8 nanometers, which is just perfect to be able to adsorb the free volatile phenols and also prevent adsorption of desired compounds,” Gore said.
While the results from their work are not published, Gore and Patton’s efforts are a small fraction of the department’s project to prevent smoke taint from ruining wine bottles.
This work is part of a larger effort by winemakers and scientists to improve the quality of affected wines; since 2020, the United States Department of Agriculture has dedicated about $5 million of its $27 million annual grape research budget to smoke exposure research, with UC Davis as a major hub of ongoing work.
For more information about the department’s resources and ongoing work, visit the UC Davis Department of Viticulture and Enology’s wildfire and smoke exposure resources webpage.
Written by: Jaclyn Bounlutay — science@theaggie.org
Dining and Cooking