Evaluation of passive samplers as a cost-effective method to predict the impact of wildfire smoke in grapes and wines.

Abstract

Wildfire smoke exposure alters grape composition, potentially resulting in "smoke tainted" wines. This has been correlated with elevated levels of smoke-derived volatile phenols (VPs) in grapes and wines. This work sought to create a predictive tool that could correlate levels of VPs in smoke with concentrations in grapes and wines. Therefore, passive samplers and Cabernet Sauvignon grapes were intentionally exposed to various smoke intensities, and wines were made thereafter. As expected, concentrations of VPs in grapes and wines were positively associated with the intensity of smoke exposure. Interestingly, levels of guaiacol in the passive samplers had a strong positive correlation with concentrations in grapes (R² = 0.9999) and wines (R² = 0.9998). The passive samplers were able to accurately predict guaiacol levels in smoke exposed grapes and wines with percent errors ranging from 0.08 to 11.3 %. These results suggest the capability of passive samplers to act as a monitoring system in vineyards during smoke events.