Every connoisseur knows aging is one of the most integral and consequential elements in the whiskey making process. The choice of grain, the quality of the malt, whether it is single malt or a blend of malts, the exact method of distillation and the recipe of the master blender are pivotal elements. But it is aging that imparts the unique characteristics in a whiskey. The same whiskey made by the same brand using the exact same process will have different tastes and flavors depending on the aging process. The simplest aspect of aging is how long the whiskey has been allowed to mature. The more complicated aspect of aging is the exact choice of barrel. You can even do your own aging at home now by buying a small oak barrel whiskey making kit.

Why is Whiskey Aged?

The classification of scotch whiskey is a post industrialization concept, wherein a whiskey must be matured for at least three years in Scotland to be called scotch. Whiskey anywhere in the world should be aged for a certain period of time and must be made from one or more of the grains accepted as the primary raw material. Bourbon whiskey has no minimum ageing requirement unless it is straight bourbon. There is no capping to how long whiskey should be aged. Although three years is the minimum for scotch and two years for straight bourbon, most fine whiskeys are aged for anywhere from eight to twenty five years.

Whiskey is aged for flavor, color, aroma, taste and distinct composition. These depend on the recipe of the whiskey and the exact factors contributing to the ageing process, including the choice of barrel and the environment in which the whiskey is aged. For instance, new oak barrels will have a certain effect on whiskey during maturation that will be different from used oak barrels, which may have facilitated ageing of another whiskey or wine. Aging whiskey in barrels is deemed by most connoisseurs as an imperative process. Those who love whiskey tend to dive deep into the exact aging process and choose their bottles accordingly.

Ageing Whiskey in Oak Barrels

Whiskey is aged to help it attain a unique character. It is aged in oak barrels because of the way the wood interacts with the whiskey. Oak is a strong wood. It is physically stronger than most other hardwoods. Oak is also a pure wood. It doesn’t have the resin canals commonly found in pine trees and rubber trees. Additionally, oak itself undergoes many changes as it undergoes the barrel making process and then facilitates the aging of the whiskey. In the process, oak imparts many beneficial properties to the whiskey.

Oak is a natural additive for whiskey. It enhances the aroma and the taste of the alcohol. The type of barrel used in the maturation process determines the exact aroma and taste. For instance, some oak barrels lend a coconut flavor to the spirit while some oak barrels lend a woody aroma, some increase the sweetness while some change the color rather dramatically. Oak also gets rid of some undesirable elements such as sulphur compounds, which are byproducts of immaturity. Oak also adds desirable elements such as converting tannins to acetals or by transforming acetic acid to the fruity esters.

The hemicellulose in oak adds wood sugars to the spirit, thereby caramelizing the aroma and lending a toasty flavor. Lignin present in oak, which is the component holding the cellulose together in the wood, yields vanillin when exposed to heat during the steaming, toasting and charring process of barrel making. Vanillin adds the smoky, sweet and spicy aromas to the whiskey. Tannins in oak enable oxidation and impart the delicate fragrance one is accustomed with in fine whiskeys. Lactones from the lipids in oak lend the strong woody aroma and flavor during the aging of whiskey in barrels.