Bottle Aging of Smoke-Affected Wines: Changes in Smoke Flavor and Chemical Composition

Winegrapes exposed to environmental wildfire smoke during ripening can be identified through analysis of volatile phenols and phenolic glycosides. While elevated concentrations of these smoke marker compounds in grapes have been shown to be predictive of composition and smoke flavor in young wines, recent research has demonstrated that not every wine produced from smoke-exposed grapes will inevitably have discernible smoke flavor when assessed as young wine 6 weeks after bottling. This is supported by anecdotal reports from wine producers that wines that do not appear noticeably smoky when young become noticeably smoky during aging. Yet there is little data available to date on the chemical composition and sensory attributes of aged wines produced from grapes exposed to environmental wildfire smoke. Data are largely limited to smoke-affected wines from model studies with deliberately smoked vines, and suggest that the concentrations of volatile phenols and glycosides may remain relatively unchanged after 5 to 6 years of bottle aging. To address the gap in knowledge, this study followed 49 wines made from grapes exposed to wildfire smoke during the 2019-2020 ripening season and reports the results obtained from monitoring chemical composition and smoke flavor intensity up for to three years after bottling. Notably, the concentrations of volatile phenols and glycosides did not change significantly over 39 months in the bottle, with the exception of syringol, which increased in both smoke-affected and control wines. Significant smoke flavor ratings were consistent over the three years for the majority of the wines (73%). For nine mildly smoke-affected wines, smoke flavor became apparent in older wines, while it had not been apparent in the young wines, likely due to masking by other attributes. These data represent a substantial database of smoke marker concentrations in wine and smoke flavor to provide context when interpreting smoke marker analysis in the future.