Dynamic Viscosity Levels of Dry Red and White Wines and Determination of Perceived Viscosity Difference Thresholds

Abstract

Wine mouthfeel significantly contributes to the overall sensory perception and quality of wines. However, the influence of dynamic viscosity on the mouthfeel of dry table wines is still not fully understood. The three objectives of this study were to 1) determine the perceived viscosity difference threshold in wine using wine/xanthan gum solutions, 2) measure dynamic viscosity levels of Australian commercial dry Shiraz and Chardonnay table wines, and 3) investigate in wine samples the relationship between dynamic viscosity and chemical parameters, specifically, residual sugar, ethanol, and pH. A wine viscosity difference threshold value of 0.138 mPa·sec at 20°C was determined by ascending two-alternative forced-choice difference threshold tests with a sensory panel (n = 45). The dynamic viscosity for 34 commercial Chardonnay wines at 20°C ranged from 1.448 mPa·sec to 1.529 mPa·sec, and from 1.488 mPa·sec to 1.695 mPa·sec for 29 Shiraz wines. These results indicate that on the basis of the determined threshold values, tasters could likely differentiate wines in terms of viscosity within the viscosity range of this sample set of Shiraz, but not Chardonnay, wines. Furthermore, significant correlations between dynamic viscosity and ethanol concentration, but not for pH and residual sugar, were found for both varieties, indicating that ethanol may have been the main compositional factor that increased dynamic viscosity in commercial dry wines.