Influence of wine composition on consumer perception and acceptance of Brettanomyces metabolites using temporal check-all-that-apply methodology

Abstract

Brettanomyces spoilage in wine is due to the production of metabolites, which together create the distinctive ‘Bretty’ aroma and flavor profile associated with wine. The objective of this study was to assess the influence of three wine flavor matrices on consumer acceptance and the temporal sensory properties of wines containing high and low concentrations of Brettanomyces-metabolites. A commercial Shiraz red wine was altered through additions of whiskey lactone (oaky) and 2-isobutyl-3-methoxypyrazine (green). The Shiraz wines (unaltered, oak and green) were spiked with either low or high concentrations of 4-ethylphenol (4-EP), 4-ethylguaiacol (4-EG), and isovaleric acid (IA). All wines were evaluated by consumers (n = 105) using check-all-that-apply (CATA) for wine aroma. In-mouth flavor and mouthfeel perceptions were evaluated with temporal check-all-that-apply (TCATA) and a ranking evaluation where the top three most prominent attributes were reported. Lastly, consumers evaluated each sample on overall liking. Consumers were classified as having low, medium, or high wine knowledge level, in addition to wine industry experience. Differences in flavor and aroma attribute citation across all wine samples were described by consumers. In comparing oak and green treatments, the presence of whiskey lactone in the oak wine more strongly masked Brettanomyces associated aromas than did a 2-isobutyl-3-methoxypyrazine in the green wine. Brettanomyces metabolite-associated flavor terms commonly increased in citations by consumers when concentrations of 4-EP, 4-EG, and IA were increased from the low to high Brett levels (p < .05). At the high Brett treatments, citations of Band-Aid®, smoky, and leather flavor attributes were all significantly lower when oak was present. Consumers identified as having wine industry experience had lower liking ratings for the wine samples as compared to those without experience (p < .05). Results demonstrated the influence of wine composition on the perception of Brettanomyces metabolites, and provided valuable information to the wine industry as to how composition, or further wine style may influence the perception of wine spoilage aroma and flavors.