What is the whiskey that evaporates from its barrel during the aging process called?

Much like a child matures over time, whiskey, brandy, and other aged alcohols become more refined as they spend years resting in a barrel. The aging process is vital to many types of liquor because it gives them the color and flavor we expect.

The goal of aging or maturation is to remove harsh flavors from the raw alcohol while adding distinct flavor characteristics found in the wood at the same time.

When the raw alcohol enters the barrel it is clear and relatively flavorless, much like vodka. During the aging process the barrel wood (usually American or French oak) absorbs sulfur compounds from the liquid inside. At the same time, the whiskey picks up unique flavors and aromas from the barrel.

Because the wood is porous, over time some of the whiskey inside the barrel will evaporate. Around 2% of the total liquid inside a barrel is lost each year. This can lead to a substantial loss of product in the case of long-aged whiskeys. For example, a 15-year whiskey will have lost at least 30% of its original volume by the time the barrel is tapped, or opened. The product loss explains why whiskeys which have aged for longer periods of time are generally more expensive.

The whiskey which evaporates is referred to as the “angels’ share,” since the missing liquid presumably evaporated and wafted up to the heavens.

“The devil’s cut” refers to whiskey which is still present, but is “lost“ because it has soaked into the wood of the casks.