Garrett Lattanzio and Thomas Collins*
*Washington State University, WSU Wine Science Center, 359 University Drive, Richland, WA 99354 (tom.collins@wsu.edu)

Grapes from vineyards exposed to wildfires can result in wines that have aromas described as ashy, cigar butt, or smoky. In recent years, there have been increased incidences of wildfires in close proximity to viticultural areas. This study exposed trial vineyard blocks to simulated wildfire smoke for periods of 26 to 48 hours, replicating conditions seen in recent wildfire episodes in Washington and California. Research was carried out by smoking 60 vine sections of the WSU Roza research vineyard in Prosser, WA. Modular hoop houses were used to contain the smoke in the exposed block of vines and to cover a control block, which was not smoked. Chardonnay and Merlot were smoked using a mixture of steppe land vegetation, while Cabernet Sauvignon was smoked using a mulch of coniferous bark and wood. Smoke intensity was monitored during each trial via TSI DustTrak DRX 8533 particle monitors (Shoreview, MN). Wines were made from the fruit using research winemaking protocols. Samples were analyzed for smoke-related compounds and their glycosides using gas chromatography/mass spectrometry (GC/MS) and ultra high pressure liquid chromatography/quantitative time-of-flight mass spectrometry (UHPLC/QTOF-MS). Principal component analysis of the UHPLC/QTOF-MS data for finished wine samples showed separation between Chardonnay, Merlot, and Cabernet Sauvignon wines, and between smoked and control samples within each variety. Wines from smoke-exposed fruit contained guaiacol, syringic acid, dihydroxy-benzaldehyde, and glycosides of at least two volatile phenols. Preparation and analysis of the samples collected during this study and identification of additional smoke-related compounds is ongoing.

Funding Support: Washington State Grape and Wine Research Program