Erik Swanson,* Ignacio Arias-Perez, Yan Wen, Cristina Medina-Plaza, and Anita Oberholster
*UC Davis, 3401 Bermuda Avenue, Apt 30, Davis, CA, 95616 (ejswanson@ucdavis.edu)

In recent years, concerns have been raised regarding the reuse of barrels that contact smoke-tainted wines. Anecdotal reports from winemakers exist, stating that non-smoke impacted wines were negatively impacted by barrels that previously contained smoke-tainted wines. Thus, the current study was designed to evaluate the potential risk of reusing barrels that contained smoke-impacted wines. In a first step, the efficacy of standard barrel cleaning and sanitation procedures at removing volatile phenol smoke marker compounds from barrels that contained smoke-tainted wines was determined. Six American oak blocks were soaked in model wine, as a control, and 30 similar blocks were soaked in heavily smoke-tainted 2020 vintage Cabernet Sauvignon from Healdsburg, CA, for six weeks. After soaking, these blocks were removed, patted dry, and subjected to cleaning (hot water rinse) and various sanitation protocols such as steam and vacuum, ozone, and sulfur wick. Blocks were then shaved to depths of 0 to 4 mm, 4 to 8 mm, and 8 to 12 mm before each layer was dried, ground to powder, and extracted for chemical analysis. The extracts were analyzed by LC-MS/MS to determine the presence of volatile phenol glycosides. Free volatile phenols are naturally present in oak and would not be an indicator of smoke marker compound adsorption. Upon completion of the chemical analysis of each layer, the most effective cleaning protocol was used on a larger trial with three barrels each of non-smoke tainted wine, low-medium smoke-tainted wine, and medium smoke-tainted wine. Upon cleaning, these barrels underwent the same analysis as the oak blocks and their corresponding shavings. Analysis is ongoing and the presence of phenol-glycosides in different layers of oak staves will indicate concerns regarding barrel reuse after storing smoke-impacted wines and which cleaning method is most effective.

Funding Support: UC Davis Oberholster Lab