By Mike Smith, Brewery Educator for Goose Island Beer Company

When a distillery is done using a Bourbon barrel, the life of that barrel has only begun. Bourbon barrels are frequently used to age other spirits from gin to tequila to Scotch whisky. But by law, if a whiskey was added to it again, it cannot be called Bourbon. Most distilleries send their used barrels to brokers who in turn find a new suiter for them. Since 1992, Goose Island Beer Co. has been working with these brokers to secure used barrels for aging our Bourbon County Stout, one of the most sought-after beers in the world.

Bourbon County Stout is a big, bold American imperial stout aged for 12 months in the Bourbon barrels. This robust beer pulls the vanilla, coconut, smoke, leather, tobacco, oak, and other whiskey flavor nuances out of these charred, wooden vessels. Released only once a year on Black Friday, that notoriously huge shopping day after Thanksgiving, Bourbon County Stout has beer fans camping out overnight at liquor stores around the country in hopes of securing a bottle before it’s gone.

Goose Island gets the majority of its barrels from Heaven Hill, and we use around 350 to 400 per batch. Once the barrels are emptied at Heaven Hill, they’re sent to the brewery within a two week window, ensuring that the barrel has not dried out. (This could potentially add unwanted flavors to the beer). Four to six-year-old barrels are ideal for aging Bourbon County Stout. At that age, there’s a beautiful balance of charred wood and Bourbon flavors left in the barrel… just the right amount for the big imperial stout base. When the barrel arrives at the brewery, we make sure to have a fresh batch of Bourbon County Stout ready to be poured in.

100% of the base beer for our barrel-aged varieties is made at our Fulton Street Brewery in Chicago, just down the street from the barrel-aging warehouse. After the Bourbon barrels are inspected for leaks, we make sure they are not washed, steamed, or cleaned. This means there’s always a bit of full-strength Bourbon left in the bottom, which mingles immediately with the beer being added.

The barrels are stored in a non-temperature controlled part of the warehouse where it will age for the better part of a year. The science at play inside Heaven Hill’s rickhouses continues to affect the liquid inside the barrels as they sit in our warehouse: the heat of summer builds pressure inside the barrel and pushes the beer through the char level of the staves and into the caramelized wood, all the way past the line where the Bourbon once reached. Evaporation happens as well, causing water to leave the barrel and, in turn, raising the alcohol content. The beer goes in at 11-12% ABV and exits at 14-16% ABV. The cold during the winter has the reverse effect of the heat from the summer months: the beer will contract, bringing all the new flavors from the charred oak barrel with it. Finally, after 12 months of carrying this monster of a beer, the barrels are emptied, blended together, and the beer is packaged and distributed.

And then… the hunt is on.

In 2010, the Bourbon County Brand was expanded to include variants, which are small batches of the beer made with different ingredients. Coffee, chocolate, vanilla, and different fruits are a few of the additions that we’ve experimented with. Once we found success there, we then furthered our variants line with the addition of “Reserve,” a variant that allows us to work with an individual distillery to obtain special barrels for aging Bourbon County Stout. Unlike our baseline Bourbon County Stout, the Reserve variant is not blended with any other barrels, so that we can highlight the whiskey flavors that once resided in them. Our 2018 Reserve variant was aged in barrels that held 12-year-old Elijah Craig Barrel Proof, which was voted 2017’s, “Whisky of the Year” by Whisky Advocate magazine. We are huge fans of this Bourbon, and Goose Island acquired these barrels during the summer of 2017, just a few months before they were honored with the award. The beer took on the subtle nuances of the Bourbon that was once in those barrels, showcasing just how special that Bourbon was.

In the fall, the emptying of the barrels and packaging of the beer signals the end of our relationship with that particular set of very special barrels. All of the complex flavors have been thoroughly depleted from the wood, and the soul of the Bourbon it once held began a new life in the black liquid gold that is Goose Island Bourbon County Stout. The used barrels eventually make their way back to brokers, who will usually have them re-coopered and re-charred, and then, most often, sent to Scotland or Ireland to be used for their whiskeys.

In the end, the barrel lives on…

To find out more about what happens to our barrels after they’ve aged our whiskey, visit: