The effects of ethanol and glycerol on the body and other sensory characteristics of Riesling wines

The effect of ethanol and glycerol concentration on the body, sweetness, acidity, aroma and flavour intensity, and perceived viscosity and hotness of three Riesling wines was assessed. The ethanol and glycerol contents of the wines were adjusted by addition to give three realistic levels (5.2, 7.2, 10.2 g/L glycerol and 11.6, 12.6 and 13.6 v/v ethanol). The nine treatment combinations (3 glycerol x 3 ethanol) were rated on the above attributes by a panel of trained tasters. Increased alcohol levels resulted in increased perceived hotness in all wines, and in higher body and perceived viscosity in two of the three wines. The effect of increasing glycerol content was less consistent with only one of each of the three wines showing increased viscosity and body. However, the mean viscosity ratings given to wines with 10 g/L glycerol was higher than at 5 g/L at all alcohol levels and for all wines, suggesting that differences in glycerol concentration typically displayed between dry white table wines can affect their perceived viscosity. Neither alcohol nor glycerol consistently affected sweetness, acidity, aroma or flavour intensity. Higher ratings of the abstract term 'body' were most commonly associated with higher ratings of flavour and/or perceived viscosity, suggesting that for the majority of tasters, these two attributes contributed to their interpretation of the term 'body'. Perceived hotness was not an important component of body, while the role of acidity in body perception was taster dependent.