Effect of pH and Alcohol on Perception of Phenolic Character in White Wine

The in-mouth perception of textures of white wine arising from the interactions among white wine phenolics, pH, and alcohol level was evaluated. Phenolics were extracted from white wines and added back to white wines that were adjusted to different pH and ethanol concentrations within wine realistic ranges. Adding phenolics to a white wine at pH 3.3 significantly increased its astringency, but the same addition did not contribute to the higher astringency elicited by the same wine when adjusted to pH 3.0. Higher phenolics generally increased bitterness and viscosity, but the effect depended on the source of the phenolics. Wines with added phenolics were generally perceived to be hotter, and significantly so when the wine was low in alcohol. The combined effect of phenolic content and alcohol concentration on astringency and bitterness was additive, suggesting that alcohol directly contributes to these attributes in white wines. Overall, the tastes and textures produced by white wine phenolics were more pronounced in wines with lower alcohol levels.