D. Cole Cerrato, Michael Penner, and Elizabeth Tomasino*
*Oregon State University, 100 Wiegand Hall, Corvallis, OR 97333 (elizabeth.tomasino@oregonstate.edu)

Smoke exposure to winegrapes is a growing concern for vintners, winemakers, and consumers as many vineyards in the United States and Australia reside in areas where wildfire intensity has been increasing since at least the 1950s. Wine is particularly sensitive to smoke exposure, often acquiring “ashy,” “burnt rubber,” or “medicinal” flavors or aromas after grapes are exposed to wildfire smoke and then made into wine. To better serve the industry, we have designed a method to perform a more thorough inventory of chemical compounds associated with smoke. A fuel source for smoke, barley, was chemically labeled using the stable isotope of ¹³CO₂. Upon assimilation after 10 days of ¹³CO₂ exposure, the 13C is expected to be incorporated into smoke precursor compounds such as lignin. After drying, the barley was burned and the smoke piped “cold” to Chardonnay and Pinot noir grapes grown in the Williamette Valley, Oregon, postharvest in a sealed container designed for this study. Chemical analysis using RP-HPLC, mass spectrometry, and ¹³C-NMR will be used to elucidate the chemicals potentially responsible for smoke flavors and aromas in affected wines.

Funding Support: American Vineyard foundation USDA-NCSFR