What Is the Aging Process of Whiskey Like?

aging whiskey in barrels affects flavor, richness

By Jonny Lupsha, Wondrium Staff Writer

Whiskey is distilled beer that has been aged in barrels of oak. The distilling process itself came from Africa to Europe courtesy of the Moors and spread throughout the United Kingdom by the 14th century. When whiskey is aged, how is it affected?

A glass of whiskey sits atop of a whiskey barrel that is aging product. The look of the photo has a vintage feel with a modern spirit.
The taste and aroma of whiskey comes from being stored in oak barrels while it ages. Photo by Jake Hukee / Shutterstock

The process of making whiskey is complex and time-consuming. Even before it’s properly aged, whiskey must be malted, fermented, and distilled. Then it’s aged in barrels for several years. Depending on multiple factors of the whiskey-making process—including the number of barleys used, the dilution of water in the whiskey, and others—it will be labeled differently and sold as such.

A fungus in Tennessee is currently running rampant and is fueled in part by alcohol vapors from aging barrels of Jack Daniel’s whiskey. This incident has led to multiple complaints and at least one lawsuit. So why and how do distillers age whiskey? In her video series The Everyday Guide to Spirits and Cocktails: Tastes and Traditions, Jennifer Simonetti-Bryan, Master of Wine and Certified Specialist of Spirits, uncovers the aging process of whiskey, which is crucial to its richness and flavor.

What Is Whiskey?

“If you distill wine and age it in oak, you get brandy; whiskey is distilled beer aged in oak,” Simonetti-Bryan said. “Distillation was brought from Africa to Europe by the Moors. Between 1100 and 1300 [C.E.], distillation spread in Ireland and Scotland through monastic distilleries. The Moors used this technique to make perfumes, but the monks used it largely for medicinal purposes such as the treatment for colic, palsy, and smallpox.”

Countries in the southern belt of Europe based their alcoholic beverages on grapes and wine, but in the northern belt, they had far fewer grapes, so they based theirs on grains. This is part of the reason that the Mediterranean is known for wine and barley beer is so prolific and popular in parts of Europe to the north, especially the northern isles.

Scotland and Ireland were the first producers of whiskey, and the first step is malting. Malting is the process of turning the starch in barley into fermentable sugar. At its simplest, barley is soaked in water, heated, and often infused with various flavors. Next, the barley is milled, fermented, and distilled before it can be aged.

Why Is Whiskey Aged?

Whiskey producers use various kinds of stills to distill their whiskey.

“Whichever kind of still you use, you end up with a clear liquor called aqua vitae, or water of life, which is then put in barrels,” Simonetti-Bryan said. “These oak casts give whiskey not only its color but up to 70% of its flavor. The origin, type, and length of time in barrel significantly affects the type of flavor.”

The more time that a whiskey spends in a barrel, the deeper its color becomes. Furthermore, the whiskey will become fuller and more concentrated. It will also have more subtle notes in its flavor, from caramel and citrus to chocolate and spice.

“Because oak is a porous material, the liquid inside it is subject to evaporation,” Simonetti-Bryan said. “This concentrates the flavors, but it also reduces the amount of alcohol.”

The Everyday Guide to Spirits and Cocktails: Tastes and Traditions is now available to stream on Wondrium.

Edited by Angela Shoemaker, Wondrium Daily