Buzz
I'm a huge fan of wine cask-finished whiskeys (okay, just whiskeys, but I like to imagine I have a sophisticated palate). The Glenmorangie Madeira Wood was one of my first loves in the world of Scotch, and I recently came across the Basil Hayden Red Wine Cask Finish, which combines Kentucky Straight Bourbon with bourbon partially aged in red wine casks, creating a flavor that's nothing short of spectacular (i.e., absolutely delicious).
This got me thinking about what makes it so delightful, which led me to explore the entire finishing process. Transforming raw ingredients into drinkable spirits is truly fascinating—and much more complex than what I imagined, especially compared to the still on that old TV show M*A*S*H (if you don't get that reference, well, it means you're not as seasoned as I am). Many spirits undergo aging (also known as 'maturing') to make them more palatable, because the initial distillation process often results in something quite raw. For instance, bourbon starts out as a clear liquid that lacks the character or flavor of a well-crafted bourbon—those distinctive qualities develop during the aging process in barrels made of charred American oak (white whiskey, by contrast, typically follows a different recipe or mash bill because it doesn't go through this process). According to Wine Magazine, barrel aging is responsible for both the flavor and the color of bourbon.
There are specific rules regarding aging—for a whiskey to be called bourbon, it must be aged in oak barrels for at least two years. Scotch must be aged for a minimum of three years in used bourbon barrels; añejo tequila generally ages for one to three years in used whiskey or wine barrels; and aged rum must spend at least one year in a bourbon barrel at some stage.
If so much care goes into aging a spirit, why does finishing matter for certain spirits?
What Exactly Does Finishing Mean?
Finishing refers to the process of giving a spirit its distinct flavor and color by storing it in a container—typically wood barrels that have previously held another spirit, though this isn’t always the case. It's a secondary aging technique where the already aged spirit is transferred into a new vessel to achieve a specific flavor and color. Imagine this: You distill a substance into a clear alcoholic liquid. You age it in a barrel, and it transforms into whiskey. Then, you age the whiskey in a second barrel that once contained red wine, and it becomes something like Basil Hayden Red Wine Cask Finish.
The chemistry of aging and maturing spirits is intricate, but it ultimately boils down to three primary interactions:
Subtractive: The interaction between the wood and the spirit eliminates unwanted or undesirable flavors.
Additive: The time spent in the barrel draws color and flavor notes from the vessel into the spirit.
Interactive: As the spirit rests in the vessel, it interacts with both the vessel material (e.g., wood) and oxygen.
This is essentially the same process that occurs during the initial maturing process, where the clear distillate produced in distillation is transformed into what we recognize as whiskey, rum, or tequila. The finishing step introduces secondary flavors—for instance, adding a hint of wine to a whiskey.
Another aspect of finishing is resting. Some spirits are 'rested' in a 'neutral' container, such as stainless steel or glass. These materials don't interact with the spirit, meaning there's no additive or subtractive process taking place. According to Master Distiller Harlan Wheatley, this neutral resting allows the spirit to calm and mellow without taking on additional flavors. Resting is commonly done with white spirits like pisco or tequila, but it’s also applied to whiskey and other spirits.
For a long time, certain spirits were never finished. As VinePair explains, spirits like vodka and gin were not traditionally aged or finished because they don't contain many compounds that could interact with, for example, a wood barrel. While vodka might be rested in a neutral vessel like a stainless steel tank, it wouldn’t be finished in a cask. However, this view is changing—increasingly, you'll find 'barrel rested' or 'barrel aged' vodkas and gins as distilleries experiment with new techniques. Technically, this means those spirits are no longer legally classified as vodka (which the Alcohol and Tobacco Tax and Trade Bureau [TTB] defines as 'without distinctive character, aroma, taste, or color') or gin (which the TTB only recognizes in its unaged form), but that doesn’t mean these innovations aren’t worth sampling.
Finishing is about shaping the final product by exposing it to specific materials and conditions over a defined period of time. There are several methods of finishing a liquor. One of the key factors is the history of the barrel used—what it previously contained. The wood absorbs the flavor of its former contents and then imparts that flavor back into the spirit placed inside it, resulting in a complex layer of flavors.
Here’s how some spirits are commonly finished.
Whiskey
Although a variety of spirits are finished nowadays, it’s particularly prevalent in the world of whiskey. The most typical finishing method for whiskey is using wood barrels or casks, including:
Bourbon barrels. Many whiskeys are finished in bourbon barrels because bourbon can impart flavors that other whiskeys typically wouldn’t pick up during their own aging process.
Wine casks. Whiskey is often finished in wine barrels to absorb the fruity and spicy flavors from various wines. Common options include sherry, port, madeira, and marsala barrels, selected based on how well they complement the whiskey’s taste.
Rum barrels. If you prefer a sweeter whiskey profile, finishing it in rum casks is an ideal choice.
These are just the most widely used options. You can also find whiskeys finished in vermouth, maple syrup (!), brandy, and beer barrels.
Gin
Finishing gin is becoming more popular, and during this process, the spirit adopts a whiskey-like character, often taking on a brown hue and a subtle whiskey flavor. Most barrel-aged gins are finished in unused, new wooden barrels. While traditional American or French oak is commonly used, gin makers can get quite inventive and even create custom barrels specifically to enhance their product.
Barrel-finished gin is frequently used as a whiskey substitute in cocktails, adding juniper and spice notes that whiskey lacks, thus altering the entire drinking experience. Whether this is considered a positive or negative change largely depends on whether you view gin as a refined spirit or the devil’s own brew.
Vodka
Similar to gin, vodka was once thought of as a white spirit that couldn’t be aged or finished (though it was common to 'rest' it in neutral vessels made of steel or glass), but that perspective is also shifting. After all, flavored vodkas are now widespread, and when vodka is placed in a non-neutral vessel like an oak barrel, it undergoes the same additive, subtractive, and interactive processes as whiskey (though to a lesser degree), emerging with a 'honey-like' color and unique flavor.
Vodka is often finished in both charred and un-charred oak barrels, but it’s also possible to find barrel-finished vodkas that have been aged in wine barrels, or even bourbon or other whiskey barrels.
Rum
While rum has traditionally only undergone a single aging process in bourbon barrels, in recent years there has been a surge in 'finished' rums. These 'cask-finished' rums start with their usual maturation in bourbon barrels and then spend a few additional months in other types of casks, with wine casks being the most popular. Sherry, port, and cognac casks are frequently used to complete the aging process. Rum has also been finished in various whiskey barrels, aside from bourbon, and even in tequila barrels.
Tequila
Tequilas vary in terms of aging: Blancos are typically bottled right after distillation or after only a minimal amount of time, while reposados are aged for up to a year, and añejos are aged for at least a year, sometimes up to three. Like vodka and rum, tequila wasn’t traditionally finished, but this trend is changing. You can now find tequila that’s been finished in Scotch barrels, bourbon barrels, and wine barrels, especially sherry casks.
Brandy
You might notice a recurring theme here: traditionally, brandy wasn’t thought of as being 'finished' in secondary vessels, though an initial maturation in oak barrels is standard. Additionally, certain brandies, like pisco, are legally required to rest in neutral vessels for a while. However, the trend of finishing brandy in wine barrels and even whiskey barrels is becoming more common.
Finishing can introduce additional flavor and complexity to a spirit, especially when the choice of vessel material and its prior contents are carefully selected to shape a distinct flavor profile. While some argue that finishing something like gin is just a marketing gimmick, ultimately, what truly matters is whether you enjoy the result. Which means you have the enjoyable task of sampling many spirits ahead of you.
