Ethanol Difference Thresholds in Wine and the Influence of Mode of Evaluation and Wine Style

This study sought to determine the minimum change in ethanol concentration (ETOH) before consumers could perceive a difference in wine (ethanol difference threshold, EDT). Ethanol difference thresholds were determined orthonasally and retronasally in four base wines in order to investigate the effect of wine style, evaluation mode, and initial ETOH on EDTs. Wines were Chardonnay with 11.6% v/v ETOH (CL), Chardonnay with 13.4% v/v ETOH (CH), Zinfandel with 11.5% v/v ETOH (ZL), and Zinfandel with 13.4% v/v ETOH (ZH) Individual best-estimate thresholds were determined for 13 Asian and 13 Caucasian subjects using the ASTM method E679-04. Group ethanol difference thresholds (% ethanol, v/v; orthonasally and retronasally, respectively) were CL: 0.50 and 1.20; CH: 0.58 and 1.03; ZL: 1.08 and 1.32; and ZH: 1.14 and 1.31. Significant effects on ethanol difference thresholds were found for wine style, evaluation mode, and their interaction, but not initial ETOH. Differences in best-estimate thresholds were observed for ethnicity, wine consumption level, sensory panel experience and experience*gender, but not for gender. While ethanol difference thresholds in wine were found to be lower than previously reported, the results raise questions about the rationale underlying some alcohol adjustment decisions and practices in industry.