You don’t have to be a whiskey expert to know that barrel aging is an absolutely essential part of the modern production process. But you may not be aware that the earliest whiskey drinkers took it straight from the still. In fact, this practice went on for centuries until an accident of history changed the game forever.
Spanish sherry was all the rage among the French aristocracy in the 1800’s, and it wasn’t long before those empty sherry casks started to pile up. Scottish distillers in need of shipping solutions started buying up the empty barrels, and unknowingly ushered in a new dawn for whiskey production.
Soon enough, distillers began to notice that the longer the whiskey spent in barrels, the richer the flavor and color became. And the rest, as they say, is history.
So the next time you’re sipping on your favorite whiskey, take a moment to appreciate the clever Scottish distillers who brought that one-of-a-kind taste to life. And in the meantime, brush up on your knowledge of the barrel-aging process.
The types of barrels are important
First, an important distinction. All barrels are casks, but not all casks are barrels. A “barrel” is a large cask (usually 50-53 gallons). Most whiskey barrels are made of white oak, which is a strong, moldable wood found throughout North America and Europe.
The tree’s place of origin affects the way flavors are imparted during the aging process. Wood from colder climates, where trees grow more slowly, have a tighter wood grain and more concentrated flavors that take longer for the spirit to absorb.
The typical steps of the barrel aging process
A bit of barrel science
While lay people like us rely on distillers to manage the science behind barrel aging, it’s not a bad idea to get a handle on a few of the finer points.
Don Livermore, master blender for Canada’s Hiram Walker and Sons, compares the three main compounds in wood to a brick wall. According to Livermore, cellulose and hemicellulose are the bricks, and lignin is the mortar.
“Cellulose and hemicellulose will contribute caramel, toffee, nutty, maple, cardboard or cotton candy notes to whiskey, whereas lignin contributes vanilla, smoky, leather, spice, creamy or medicinal flavors,” says Livermore.
Another important point to remember is that although barrels appear solid, they do allow airflow—gradually inviting oxygen into the aging process while allowing evaporation to take place.
Why barrel aging matters in whiskey production
The importance of aging whiskey in barrels can be distilled (couldn’t help it) down to three main points: flavor, color, and filtration.
Flavor: Experts say 60-80 percent of a whiskey’s taste comes from the barrel. That’s why distillers pay such close attention to the type of wood, age, size and previous liquid in the barrel.
American white oak often produces a sweet taste with notes of vanilla and caramel, which is a typical bourbon flavor. European oak has a spicy taste and stronger wood notes. Charring contributes to flavor by removing tannins and deepening the flavor of sweet-tasting compounds like vanillin.
As you might imagine, whiskey stored in a new cask absorbs the most flavor from the wood. (By law bourbon must be aged in a new cask.)
Color: Whiskey gets 100 percent of its color from the barrel. As changing temperatures move the whiskey in and out of the porous wood, the alcohol draws out pigmentation that gives it that signature color. Typically, the longer it stays in the barrel, the darker in color the whiskey becomes.
Filtration: The char on the inside of a barrel filters out chemical impurities that affect the final taste and quality of the whiskey. This process helps the flavor evolve from a harsh “moonshine” taste to the smooth, mouth-watering goodness of a fine whiskey.
So let’s raise a glass to barrel aging, the happiest of historical accidents. If you’re interested in taking your whiskey journey to the next level, check out our exclusive barrel ownership options.
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