LOUISVILLE, Ky. (FOX 56) — A barrel maker is called a “cooper” and a Louisville factory is full of them around the clock — men and women who carry on a skill that dates back to 300 B.C.

Demand for barrels has never been greater. Kentucky filled two and a half million of them last year and there are eleven million barrels aging in warehouses, filled with bourbon, brandy, and other spirits.

Tyler Mirt, the Brown-Forman Distillery ambassador, said, “We’re all struggling to keep up. It’s a great problem to have. Much better than the 70s, 80s, and 90s when nobody cared about bourbon.”

Brown Forman, the maker of such spirits as Jack Daniels, Woodford Reserve, and Old Forester, is the only distillery in the country to have its own cooperage. It’s been in Louisville since 1945.

MORE SPIRIT OF THE BLUEGRASS:

Mirt said the Louisville cooperage turns out about 2,000 barrels a day and a sister cooperage in Alabama mirrors that.

Industry experts said bourbon wouldn’t be what it is without the barrel. Much of the process is automated these days, but it still takes humans to choose the staves and bind them so they’re leakproof. Those staves, made of white oak, are packed with sugars that contain hints of many flavors, such as vanilla, toffee, or molasses. Those flavors come out when giant flames char the barrels, cracking the wood. The charring also gives bourbon its color.

“Each barrel is a fingerprint, if you think about it,” Mirt said. “You’ve got 40 to 50 different trees in play in each barrel, so not one will ever be chemically identical or taste exactly like the other. That’s what gives us single barrels. That’s what allows us to create different expressions within a lineup.”

It’s a fascinating process to watch from start to finish as barrels take shape, get fired up, and roll on to their destination.

Mirt said the coopers are proud of what they’ve accomplished at the end of the day, carrying on a tradition that has stood the test of time.

The barrels made at the cooperage have a 60-year life. They’ll be used to store bourbon for four to 10 years, then go on to Scotland, Ireland, or the Caribbean to continue their use holding rum tequila or vodka.