Ethanol (alcohol) interacts with sensory attributes of wine and can decrease the potency of aromas as the amount of alcohol increases, according to Dr. Carolyn Ross of Washington State University.

Ethanol affects the solubility and volatility of binding properties, masking or swamping out other aromas, said Ross, WSU food science professor. Research literature also shows that ethanol enhances heat, roughness, and can be bitter, she said, adding that it interacts with major wine components like glucose, glycerol, and catechin.

“Ethanol affects the head space of wine so that you smell fewer compounds when you take a whiff of wine,” said Ross, manager of WSU’s sensory evaluation unit. Ross has conducted several studies on the effects of ethanol on the sensory perception of wine, using trained panelists to learn when consumers can notice changes in alcohol levels and detect sensory differences.

In her sensory studies using model and actual wines spiked with odorant compounds, she found that as alcohol concentrations increased, panelists detected a decrease in fruity, floral, and caramel aromas and an increase in sulfur aromas and flavors.

“Ethanol was the main factor influencing sensory perceptions of wine,” she said. “As ethanol increased from 8 to 16 percent, we saw an increase in sulfur notes and a decrease in the fruit and ­floral notes.”