Ethanol is the second major component of wine after water and exhibits important sensory properties. Previous studies suggested that its bittersweet taste varies according to the alcohol content and the matrix. However, the organoleptic impact of ethanol on wine remains largely ambiguous. Various sensory tests were carried out with a trained panel and the results were statistically analyzed. Tastings revealed that variations of ethanol content usually observed in dry wines have no direct effect on sweet taste of wine. The role of ethanol in white wine bitterness was also studied, revealing its ability to impart the perception of bitterness due to sensory interactions with other constituents. Moreover, a threshold effect was observed between 7 and 10% alc. vol.. These results underline the importance of sensory interactions in the perception of taste and illustrate the role of matrix effects.