Alcohol is an exceptional solvent. It extracts and holds onto the flavor compounds (phenols, esters, aldehydes, and fatty acids) that give whisky its character. When whisky is maturing in a cask, the interaction between the spirit and the wood is driven by the alcohol concentration. At cask strength (often 55-65% ABV when bottled from the cask), the whisky contains the maximum possible load of these flavor compounds.
However, high alcohol also brings a physical sensation: heat. Ethanol activates the TRPV1 receptors on your tongue, the same receptors that detect heat from chili peppers. A whisky at 60% ABV can be so "hot" that it overwhelms your palate, making it impossible to taste the delicate vanilla, fruit, spice, and oak notes underneath. It can also cause a numbing effect. percentage of alcohol in whisky
This is why most professional whisky tasters add water. A few drops can lower the ABV to a "release point" (often between 35-45%) where the flavor compounds are no longer locked in by the alcohol matrix and become more volatile, releasing their aroma. Alcohol is an exceptional solvent