What is the characteristic taste imparted by barrels during aging?

The characteristic taste imparted by barrels during aging is primarily known as oak flavor. When spirits or wines are aged in oak barrels, various compounds from the wood interact with the liquid, leading to distinct flavors associated with oak. These include not just the basic taste of oak itself but also the extraction of vanillin, which contributes to vanilla notes, lactones that can give coconut flavors, and other chemical compounds that can enhance the spirit's overall complexity.

While cherry, vanilla, and cinnamon flavors can certainly be present in aged spirits, they typically arise from a combination of the base ingredients (like grains or grapes), fermentative processes, and sometimes the specific type of barrel used. However, the predominant flavor derived specifically from the oak material of the barrels is what is referred to as the oak flavor.