All Good Things Get Better with Age

From rum and brandy to starka, whiskey, and tequila—these spirits all share one common trait: their color. All are clear when they come out of the distiller; some remain so, while others acquire color during the aging process. But color is not the only change that occurs during barrel aging.

If you've ever wondered how these spirits become so refined, here lies the secret in their aging process. If you're seeking authentic taste and essence that stands out, then barrel-aged spirits are what you desire.

How Does Barrel Aging of Alcohol Work?

Aging involves storing distilled spirits in barrels for a specified time. The purpose of aging is to eliminate the harsh flavors of raw alcohol while enriching it with a unique taste and aroma derived from the barrel wood.

When alcohol is poured into a barrel, it is relatively colorless and tasteless. During its time in the barrel, alcohol gradually absorbs flavor and color from the wood, which explains why some spirits, like whiskey and brandy, have a warm amber hue. In contrast, clear spirits like vodka remain colorless because they are not aged that way.

To achieve optimal taste, color, and aroma, spirits typically mature for about three years.

Barrel aging is a crucial stage in producing high-quality whiskey and other distilled spirits. This centuries-old practice, deeply rooted in history, enriches the final product with complexity, flavor, and aroma. Understanding the nuances of barrel aging, choosing the right barrel, and maintaining ideal conditions are essential for achieving the desired results.

Ideal Barrel Aging Time

The aging period for whiskey and other distilled spirits can vary significantly, usually ranging from three to twenty-five years. The specific duration depends on the type of whiskey and the desired flavor profile. Longer aging can lead to more complex and refined flavors. However, small barrels have an unfavorable ratio of alcohol volume to the internal surface area, which can lead to "over-oaking" the distillate—hence, small barrels (20-50 liters) are only used for finishing, and larger barrels, at least 100 liters, are chosen for long-term aging.

Types of Wood Used for Barrels

Different types of wood impart unique flavors and characteristics to distilled spirits. The most commonly used wood types are:

  • American White Oak: Ideal for aging whiskey, bourbon, and Scotch. Known for imparting vanilla, caramel, and coconut notes.
  • Mizunara Oak: Known in whiskey as Japanese oak, it features unique notes of spices, oriental incense, and sandalwood.
  • European Oak: Adds spicy, vanilla, and bitter undertones to spirits. It has a denser fiber structure and is more absorbent, allowing deeper penetration of the spirit during aging.
  • Sessile Oak: Also known as Irish oak, it is popularly used for aging cognac.

Which Barrel to Choose?

It depends on the purpose—if you want to place a small keg on a wedding table, it doesn't matter much as the alcohol will stay in it for only a few hours. It won’t be harmed by a tap or even, heaven forbid, sealing with rush or beeswax. However, if you're thinking about long-term storage, ensure the barrel has split staves, not cut ones—look at the grain direction and how it’s arranged from the head's side. If the barrel has hoops screwed on (yes, it happens, unfortunately)—go elsewhere immediately. Avoid barrels with a tap or lacquered exterior (beeswax is also NOT okay here!); a good barrel doesn't need additional sealing. Do not agree to engravings (laser engraving reduces the head’s breathing surface) or barrel painting.

The optimal capacity is from 100 liters and up; using smaller barrels requires significantly shortening the maturation time. Barrels up to 30 liters are essentially suitable only for serving (e.g., weddings, parties, festivals) or finishing, to give the distillate a final touch. For this purpose, we use smaller barrels previously containing interesting wines, meads, or even beers.

How to Prepare a Barrel?

Fill it with alcohol :) Remember not to fill the barrel with water before use—if the seller advises this, it means they know their barrel is of low quality. If the barrel will be empty in a dry place, you can mist it with water from the outside, but never pour water inside. Diluting alcohol for barrel aging is an individual matter, usually around 50-something percent for new barrels or >60% for used barrels. For used barrels, it’s crucial that the alcohol poured in has a higher concentration than the one previously aged in it.

The Role of Wood in Flavor Development

The wood of the barrel plays a crucial role in developing the unique taste and aroma of whiskey. Experts often char the barrel interiors with fire. This process helps the oak release its natural sugars, caramelizing the tannins into vanilla notes. Depending on the level of charring, new flavors develop to varying degrees. Light charring gives a sweet, toasty flavor, while heavily charred barrels impart sharper flavors with notes of spice and smoke. The darker the wood, the deeper the alcohol’s color.

For example, brandy is usually aged in lightly toasted barrels, while American whiskey often ages in heavily charred barrels.

Climate and Storage Conditions

Climate and storage conditions are crucial for the aging process. Temperature and humidity affect how alcohol interacts with the wood. Higher temperatures can accelerate the aging process, while constant humidity helps maintain the barrel’s integrity and prevents leaks. Distilleries carefully control these factors to ensure the best possible outcome for their spirits. The humidity of the barrel room is key to keeping it in good condition, even when it’s not filled with alcohol.

The Best Alcohol for Barrel Aging

To achieve optimal results, the alcohol used for barrel aging should be distilled in a copper still. Copper stills are known for their ability to remove sulfur compounds from the distillate, resulting in a cleaner, clearer alcohol. Therefore, alcohol distilled in copper is an ideal candidate for barrel aging, allowing the wooden flavors to flourish without undesirable notes.