Safeguarding US Vines and Wines from Wildfire Smoke

Authors: Rumbaugh, Arran

Submitted to: Online Publication
Publication Type: Popular Publication
Publication Acceptance Date: 7/23/2025
Publication Date: 7/31/2025
Citation: Rumbaugh, A.C. 2025. Safeguarding U.S. wines and vines from wildfire smoke. Online Publication. https://graperesearch.org/2025/07/29/safeguarding-us-vines-and-wines-from-wildfire-smoke/.

Interpretive Summary: Wildfires present a significant threat to the grape and wine industry, specifically across the western United States where the frequency and severity of wildfires have been increasing. While direct damages to property are notable, an emerging concern is smoke exposure in vineyards that can lead to smoke taint in wines characterized by undesirable smoky and ashy flavors. However, the precise levels of smoke in a vineyard that can cause such and impact in the final wines remains unclear. To address this issue, a two-day workshop organized by ARS researcher Arran Rumbaugh in November 2024 brought together 50 scientists and industry stakeholders to explore key concerns and research directions. Discussions centered on detection, establishing exposure thresholds, vineyard prevention strategies, mitigation in wineries, and utilizing atmospheric models for risk assessment. Researchers have identified volatile compounds like guaiacol, cresols, and thiophenols as key markers for smoke taint, with emerging analytical tools like chromatography aiding detection. Moving forward, priorities include developing affordable testing methods, creating predictive models for smoke exposure, and exploring prevention strategies such as smoke-resistant grapevines. Despite progress, variability in grapevine responses and environmental factors complicate universal solutions. Ultimately, this research aims to safeguard wine quality and the economic viability of the industry amid increasing wildfire risks.

Technical Abstract: Each year the grape and wine industry faces the risk of wildfire smoke exposure in vineyards. As wildfire seasons become longer and more intense across the western United States, researchers are dedicated to understanding how smoke impacts grapevine physiology, grape composition and wine quality. While it is established that smoke could potentially lead to a phenomenon known as smoke taint- characterized by undesirable smoky and ashy flavors due to chemical changes in the grapes and wines- it is unknown how much smoke is too much. Therefore, ARS researcher Arran Rumbaugh organized a two-day workshop, held in November 2024, to examine the state of current research, key industry concerns, and future directions. Approximately 50 university scientists, ARS researchers, and industry stakeholders were invited to engage in structured discussions across five topical areas: detection and monitoring, establishing thresholds and baseline values, prevention in the vineyard, mitigation in the winery, and utilizing atmospheric modeling to assess risk. Research has shown that when wildfire smoke lingers over vineyards, grapevines absorb certain volatile compounds released from burning vegetation. These compounds are later transformed into odorless forms by the plant itself and stored in grape skin and pulp. During fermentation—or even upon consumption—those compounds are released back into their aromatic form, producing smoky aromas that can obscure a wine’s intended profile. In response, researchers are working to establish best practices that will enable growers and winemakers to detect smoke impact early, even before any sensory changes are apparent in the wine. Analytical tools like gas and liquid chromatography, alongside small-scale test fermentations, known as nanofermentations, are helping identify key chemical markers of smoke taint. Among them are compounds like guaiacol, cresols, syringol, and their glycoconjugates, as well as a newly identified group called thiophenols, which may be especially responsible for that lingering ashy aftertaste. Yet detection alone is not enough. The industry needs actionable guidance on prevention and real-time decision-making. Growers want to know: When is it safe to harvest? Can a crop still be used? What treatments in the winery work? And how can we model smoke exposure during a fire event? On going research priorities include: • Building a baseline database of smoke compounds in grapes and wines, • Developing quick, affordable testing tools for vineyards and wineries, • Using atmospheric models to predict vineyard-level risk, • Exploring prevention strategies like barrier sprays or breeding smoke-resistant vines, • And designing winery-based techniques to reduce or neutralize the presence of smoke compounds. While progress is being made, many knowledge gaps remain. Grapevine physiological responses are still being investigated to properly develop prevention and mitigation tools. However, different grape varieties may react differently to the same level of smoke exposure. Complicating matters further, variables such as environmental conditions, vineyard management practices, and winemaking styles make it unlikely that a universal solution will emerge. Instead, future strategies will need to be flexible and based on regional conditions. Ultimately, researchers hope that by better understanding the science of smoke taint, the industry can make more informed choices during fire seasons and preserve the quality, identity, and economic viability of American wines. As one researcher put it, this work isn’t just about chemical analysis. It is about safeguarding a tradition rooted in the land, the fruit, and the people who cultivate it.