Baseline Levels of Smoke-related Volatiles and their Glycosidic Precursors in California Grapes and Wines
The increasing incidence of wildfires in grape growing regions of California and the West Coast has highlighted the need for enhanced understanding of the levels of volatile phenols and their non-volatile glycoside precursors that contribute to smoke taint off-flavors in grapes and wines. In this project, we measured ten volatile phenols in non-smoke exposed grapes to begin to understand baseline levels of these compounds in red and white grape varieties. Free and total levels of guaiacol, creosol, phenol, 4-ethylguiacol, o-, m-, p-cresol, 4-ethylphenol, 4- methylsyringol, and syringol were measured in grapes from different regions of California. Air quality data for these regions is also presented. We will obtain data over a minimum of two years in order to begin to assess year to year variability. We have submitted a proposal to continue this work in 2022-23.