Rosemary Veghte, Madeleine Higgins, Payton Booth, Garrett Lattanzio, and Thomas Collins*
*Washington State University, 359 University Drive, Richland, WA 99354 (tom.collins@wsu.edu)

The wildfires affecting the Pacific Coast states during the 2017 harvest season have increased concern over the impact of smoke on the quality of grapes and wine. With this heightened concern comes the need to evaluate the compositional differences in smoke generated by fires from different fuel sources to determine how fuel source might affect aroma and flavor in wines. This study quantitatively evaluated the compositional differences in the combustion products of 16 assorted plants native to southeastern Washington. These include sagebrush, cheat grass, rabbitbrush, and puncture vine, among others. An amount of desert plant material sufficient to burn consistently for 5 min in triplicate was collected in July 2017 and dried two to five days (depending on plant type) before being burned in a modified commercial smoker. Smoke particle concentration was monitored using a TSI Sidepak AM510 aerosol monitor (Shoreview, MN). Smoke particles were collected using Whatman glass microfiber filters (1.0 µm pore size) positioned in-line with the smoker exhaust. Three 1cm discs were removed from each filter and analyzed using solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS). Preliminary results showed differences in the composition of smoke produced by burning the 16 different botanicals, with p-cresol, m-cresol, 4-ethylphenol, and syringol present in the highest concentrations in sagebrush, while the conifer bark mulch exhibited the highest levels of guaiacol and creosol. By contrast, rabbitbrush contained several late-eluting, tar-like polyaromatic hydrocarbons that were not present in most samples, but it had lower concentrations of guaiacol. Future work will focus on understanding the relationship between wildfire fuel source and the presence of various smoke taint compounds found in grapes and wine.

Funding Support: Washington State Wine Commission