Thomas S. Collins,* Scott C. Frost, Bojana Leonard, Danielle J. Fox, James F. Harbertson, and Matthew Boenzli
*Washington State University, 359 University Drive, Richland, WA 99354 (tom.collins@wsu.edu)

Small-scale, “bucket” fermentations have gained acceptance as a way to predict the risk to wine quality from vineyard smoke exposure. However, there is no published data supporting their use. When conducted several days prior to the anticipated harvest date, wines from these fermentations can be evaluated for smoke-related aromas and flavors or analyzed for smoke taint marker compounds. In this study, bucket (5 kg) fermentations and small commercial-scale (362 kg) fermentations were conducted using fruit from a vineyard affected by a wildfire that burned up to one edge of the vineyard. We examined the effects of cultivar and fire proximity by harvesting Cabernet Sauvignon, Syrah, Grenache, and Petite Verdot fruit from blocks that were adjacent to or remote from the most fire-affected edge; for each cultivar a high- and low-impact block was selected. The sensory and chemical profiles of the resulting wines were evaluated using descriptive analysis and solid-phase microextraction-gas chromatography-mass spectrometry. Volatile phenol concentrations were comparable in both large- and small-scale fermentations and were consistent with expectations based on proximity to the fire-affected vineyard edge. However, a significant cultivar effect was also found: Petite Verdot and Syrah had higher concentrations of guaiacol and 4-methyl guaiacol than the Grenache or Cabernet Sauvignon, while the Gre- nache had more o-cresol and m-cresol than any other cultivar. Sensory evaluation found that the flavor profile of the bucket fermentations was impacted by cultivar and fire proximity. Cabernet Sauvignon wines had more fresh bell pepper aroma and astringent mouthfeel, while the Syrah wines had more canned asparagus character. Proximity to the fire increased the intensity of the peaty/medicinal aromas, but an interaction between cultivar and location was shown for wood smoke/ash intensity.

Funding Support: Washington State Wine Commission