Commercial Barrel Aging

February 8th, 2024

Scotland has long been synonymous with whisky, crafting some of the world’s most revered spirits for centuries. Its rich tradition of whisky-making has influenced distillers worldwide, setting the gold standard for aging, flavor, and craftsmanship.

February 8th marks International Scotch Day, a time to raise a glass and celebrate one of Scotland’s greatest contributions to the world.

At Midwest Barrel Co., we don’t like to pick sides when it comes to spirits. That’s why we have to point out that two neighboring countries claim to be the true birthplace of whisky—or 'whiskey,' depending on who you ask.

However, today, it’s Scotland’s time to shine for its undeniable influence on the global whisky industry.

In this blog post, we’re taking a deeper look into not only Scotch but also the oak casks that age this distinct, often smoky style of whisky. So grab your favorite bottle of Scotch off the shelf and pour yourself a glass.

It’s time to drop some barrel knowledge.

Putting aside the debate over which country created whisky, one certain fact is that Newburgh is the birthplace of Scotch whisky. It was in this small town in 1494 that monks at Lindores Abbey recorded the first mention of an early version of whisky. The document stated that one of the monks, Friar John Cor, distilled 'aqua vitae,' or water of life.

By 1644, Scotch had become so popular that the Scottish Parliament wanted its take. That was the year of the first taxes on Scotch. The story unfolds in a way many in the U.S. will find similar to the Prohibition era. Illegal Scotch became the norm.

This continued until the Scottish government passed the Excise Act in 1823, making it profitable for distillers to make Scotch legally. And just like that, those who had been smuggling Scotch found it made more sense to practice their trade above board.

The rest, as they say, is history.

By law, Scotch whisky must be aged in oak casks for at least three years—some are aged for 50-plus years. Of course, many distillers age their whisky in barrels for much longer periods to achieve the desired flavor profile. Scottish law also states that the minimum ABV for bottled Scotch is 40%.

Although some say John Cor stored his spirits in casks, it’s not entirely clear whether this was an intentional aging process like it is today or if he was simply storing the liquid in a common container for many goods and liquids at that time.

Barrel-aging as it’s now practiced may have been discovered by accident at some point in the 1800s. Before this, it’s believed most of what we’d today call Scotch was consumed directly from the still.

The accident, which we can imagine was an amazing discovery, likely first occurred after blight greatly affected Cognac supplies and Spanish sherry was imported instead. Scottish distillers bought the casks that aged the sherry and used those to send whisky back to Spain.

The results of that accident continue to shape Scotch whisky even today.

Before we take a look at how oak casks affect Scotch, we first need to cover the different types of Scotch whisky: single malt, blended malt, single grain, and blended grain. Each of these types of whisky meets the definition of Scotch: they are made from three natural cereals, water, and yeast; must be distilled and matured in Scotland in oak casks for at least three years; and must be bottled at 40% ABV minimum.

• Single Malt Scotch Whisky – Distilled at a single distillery from water and malted barley, with no other cereals added. Must be produced by batch distillation in copper pot stills and bottled in Scotland.

• Blended Malt Scotch Whisky – Made from a blend of single malt Scotch whiskies distilled at more than one distillery.

• Single Grain Scotch Whisky – Distilled at a single distillery from water and malted barley. It may include whole grains of other malted or unmalted cereal.

• Blended Grain Scotch Whisky – A blend of single grain Scotch whiskies distilled at more than one distillery.

Aside from blend versus single and ingredients, multiple additional factors influence a Scotch’s flavor—where it’s made, whether peat is used, and the oak cask used to age the whisky.

There are five regions where Scotch is distilled in Scotland: Campbeltown, Highland, Islay, Lowland, and Speyside. Each region’s whisky boasts unique flavors thanks to the surrounding natural environment. In addition, the size and shape of the still impact the whisky’s flavor. The taller the still, the lighter the flavor.

Then there’s peat. That’s the source of the smoky, campfire-like flavor featured in some Scotch whiskies. Peat is decomposed plant matter found in bogs and wetlands. It’s sometimes used to fuel the kiln that dries the barley during the malting process. Peat is similar to coal but significantly younger.

And then there’s our favorite factor in adding flavor to Scotch—the cask (or barrel)!

Did you know at least 60% of Scotch’s flavor is imparted by the cask while the liquid matures? Plus, that flavor varies widely based on the source and type of cask.

In many cases, the flavor differences begin with whether the cask is made of American oak or European oak. American oak casks are typically used bourbon barrels, while European oak casks formerly aged sherry, port, or table wines. Each previous liquid influences the Scotch’s unique flavor.

Bourbon casks are used for 95% of Scotch, according to The Scotch Malt Whisky Society. These casks are often broken down, shipped overseas, and then reassembled into larger casks. When it comes to maturing Scotch, they’re known to produce lighter colors and impart sweeter flavors of coconut and vanilla. European oak delivers darker colors and imparts flavors similar to fruitcake, raisin, dates, and toffee.

It’s a common misconception that the longer a Scotch is aged in casks, the better it will turn out. However, Scotch is just like other whiskies—older does not always equate to higher quality. It all comes down to taste and preference.

It also boils down to the barrel. Like any aged spirit, Scotch depends on cask quality, previous contents, and the right timing.

As Mark McLaughlin, the co-founder of Old Line Spirits, tells Food & Wine:

“Harvesting the right barrel at the right time to achieve the desired profile is an art, and age is one of several factors at play.”

This is true with Scotch and any other aged spirit. It all comes down to the barrel—its previous contents, age, and composition.

If you’re on the hunt for the perfect barrel, contact us. Our team will hook you up with quality barrels backed by our brand promise of Damn. Good. Barrels.™