A combination of thiophenols and volatile phenols cause the ashy flavor of smoke taint in wine

• Published in: Food chemistry advances 2023-10, Vol.2, p.100256, Article 100256
• Main Authors: Tomasino, E., Cerrato, D.C., Aragon, M., Fryer, J., Garcia, L., Ashmore, P.L., Collins, T.S.
• Format: Article
• Language: English
• Subjects: 2-Methoxybenzenethiol; 2-Methylbenzethiol; Grape smoke exposure; LC-MS/MS; Pinot noir
• ISSN: 2772-753X; 2772-753X
• DOI: 10.1016/j.focha.2023.100256

•Thiophenols and napthalenethiols were present in ashy flavor standard.•Thiophenols were found in higher concentrations in wines made from smoke exposed grapes.•A combination of thiophenols and phenols resulted in ashy flavors in wine. Grapes exposed to wildfire smoke can develop reduce wine quality, imparting unpleasant smokey and ashy flavors. Research has primarily focused on the increased concentration of volatile phenols (VPs) in grapes and wine acquired from smoke. This study was undertaken to determine the chemical compounds that cause the ashy flavor in wines produced from smoke exposed grapes. The chemical composition of a tasting standard produced from charred leeks was determined using UPLC-QToF/MS. Several thiol derivatives were identified. Analyses of smoke-impacted wines and grapes revealed the presence of thiophenols, napthalene thiols, and additional thiol-derived compounds. LC-MS/MS of wines produced from smoke-exposed grapes showed higher concentrations of thioguaiacol and thiocresols. Chemical causation of smoky and ashy flavors by these compounds was investigated using sensory descriptive analysis. Wines with both thiophenols and VPs were described as ashy and smokey, contributing to more than 90% total variance for each wine.