Influence of Ethanol on Flavor Perception in Distilled Spirits

People often enjoy drinking distilled spirits on the rocks or with a splash of water to open up the flavors. From a physicochemical perspective, the addition of water (dilution of ethanol) affects the spirit's matrix in several ways. These include a decrease in surface tension, a change in the structure of the liquid water and ethanol matrix, and a change in volatile compound partitioning and release from the bulk solution. From a physiological perspective, the dilution of ethanol partially reduces the pungency associated with high ethanol content, and more importantly, it increases olfactory sensitivity to the aroma compounds. However, there is not enough evidence to prove which effect dominates nor are there any systematic studies to link sensory perception alteration to quantitative data. This chapter discusses the influence of ethanol on flavor perception from both physicochemical and physiological perspectives and provides additional insights into the physiological effects of ethanol on individual aroma compound perception based on our own recent studies.