From descriptive analysis to rapid sorting: sensory approaches for the identification of smoke-affected Cabernet-Sauvignon wines

Abstract

The increasing incidence of wildfires in the United States has raised the risk of vineyard smoke exposure, consequently possibly changed grape composition and the development of negative sensory attributes, commonly referred to as smoke taint (1.). During smoke exposure, grapes absorb volatile phenols that are subsequently glycosylated into odorless bound precursors capable of releasing aroma-active compounds during winemaking and aging (2.). The objectives of this study were to establish threshold levels of free and bound volatile phenols associated with undesirable sensory impacts in wine and to evaluate efficient sensory approaches for differentiating smoke-affected wines. A proof-of-concept design was implemented in which harvested grapes were exposed to smoke generated from various fuel sources, such as wood and grass, at defined intensities. Experiments conducted in 2023 and 2024 focused on Vitis vinifera L. cv. Cabernet-Sauvignon is a cultivar of significant importance to premium wine production. Grapes were smoked in a chamber to achieve three exposure levels (low, medium, high) in addition to a non-smoked control. Wines were produced following a standardized UC Davis winemaking protocol and analyzed for volatile phenols and their glycoconjugates using GC–MS/MS and LC–MS/MS, respectively (4.,5.). Sensory evaluation comprised descriptive analysis with a trained panel and a rapid sorting task performed by experienced wine assessors utilizing a targeted smoke-related lexicon (3.). In 2023, Cabernet-Sauvignon (CS) wines subjected to high smoke exposure were consistently distinguished through descriptive analysis, while separation among the different treatments improved in 2024. Given the substantial time and resource requirements of descriptive analysis, rapid sorting was evaluated as an alternative. The results from the CS wines suggest that sorting may offer a “quick and dirty” method for identifying sensory differences among smoke-affected wines and may serve as an efficient screening tool in conjunction with chemical analysis.

References

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