Anita Oberholster,* Yan Wen, Samnang Hay, Sandra Dominguez Suarez, Jesse Erdmann, Bishnu Neupane, Charles Brenneman, Hildegarde Heymann, Scott Lafontaine, Raul Cauduro Girardello, and Arran Rumbaugh
*UC Davis, One Shields Avenue, Davis, CA 95616 (aoberholster@ucdavis.edu)

The increasing incidence of wildfires in winegrape-growing regions poses a significant risk to the grape and wine industry. One risk is the potential of persistent exposure to smoke to compromise the quality and value of winegrapes and adversely affect wines made from smoke-exposed grapes. A wine is seen as smoke-impacted or -tainted when there is an overpowering smoky, medicinal, chemical, burnt, or ashy aroma on the nose and a distinctive retronasal ashtray-like character in the mouth. Several solutions for smoke taint have been promoted, such as treatment with enzymatic enzymes, fining, reverse osmosis, and spinning cone treatments. These amelioration techniques were investigated using smoke-impacted wines made from Cabernet Sauvignon grapes from Napa and Lake Counties (UC Davis Teaching and Research Winery) in 2017 and 2018. The impact on wine composition: specifically, smoke-taint marker compounds (both free and bound volatile phenols as determined by GC-MS and LC-MS/MS) and other key volatile and non-volatile compounds important for wine quality were evaluated to determine their efficacy. Additionally, descriptive analysis was performed on the treated and untreated wines. Results indicated that although most amelioration techniques removed some smoke taint markers (mostly free and some bound) and decreased smoke taint perception, they lacked specificity and impacted the overall character of the wine in a negative way. However, the im- pact depended on the level of treatment needed and the decrease in mouthfeel could be adjusted using TTB-approved products or blending. Amelioration techniques were not 100% fixes of smoke taint, but significantly decreased smoke-taint perception. Further research could result in recommendations regarding the feasibility of treatment success based on the wine matrix, so that winemakers can make informed decisions.

Funding Support: American Vineyard Foundation