If you're a fan of whiskey, you've also got a deep investment in barrels, whether you know it or not. It might sound hyperbolic, but it's true: Without barrels, there would be no whiskey as we know it. Aging in wooden casks is what gives the spirit much of its flavor, and so the care, maintenance, and sourcing of those barrels is a crucial element of any distillery. Just ask Ger Buckley, who, for almost 40 years, has served as the Master Cooper (read: barrel-maker) at Jameson's distillery in Midleton, Ireland.

You'd be hard-pressed to meet someone more enthusiastic or knowledgeable about the history and construction of whiskey barrels than Buckley. He's studied every aspect of cooperage, from its history (cask making dates back to the Pharoahs in Egypt) to the forestry conditions that produce the best kind of wood for constructing barrels. He even keeps an eye out for barrels in pop culture: the Game of Thrones barrels, Buckley says, all have wooden hoops on them rather than the steel ones of the industrial revolution, consistent for the economic climate of Westeros.

Buckley is a fifth generation cooper — or as he noted, "fifth generation that I can prove," though his family's involvement in the barrel-making industry likely dates to the early 19th century. He's one of a very small group of full-time professional coopers in Ireland. At the turn of the 20th century, there were, Buckley estimates, around 10,000 coopers operating in Ireland, constructing everything from beer barrels to household items like butter churns. Now, by his count, there are just four coopers operating in the entire country.

Buckley began his apprenticeship for the trade when he was 17 under the watchful eye of his father, learning the nuances of mending and crafting casks. "He was a really good cooper, and I'm not just saying that because he’s my father," Buckley said. "He had four or five apprentices in his lifetime, which is an indication of the quality of his work." Buckley’s father was also a cooper at one of the distilleries in the Jameson family, so he's been in a distillery for all of his working life.

The barrels that Jameson uses aren’t made from scratch, thanks in part to an Irish timber shortage in the 19th and 18th centuries. Instead, the distillery imports two kinds of barrels: sherry casks from Spain and bourbon barrels from Kentucky. Every bottle of Jameson is a mixture of the whiskeys aged in those two kinds of casks, balanced to get the characteristic notes of vanilla and spice. (Irish law requires the spirit to be aged at least three years before it can officially claim the title "whiskey.") Buckley inspects every cask that comes into the distillery, examining them for damage or flaws in the wood grain that would affect the taste of the whiskey or the integrity of the barrel, and then brings any flawed candidates back into the cooperage to mend.

Jameson's cooperage is a large, sawdust-sprinkled room filled with hundreds of barrels in various stages of repair. The only materials allowed in the construction of the casks are timber, for the barrels, and steel, for the hoops: No glue, no silicone, only the occasional river reed to help seal the top of the barrel. Once barrels are filled, they swell to accommodate the whiskey and become watertight. But the slightest flaw in the barrel making — an imprecisely angled stave, a weakness in the timber — means that the barrel could leak its valuable contents. It’s an exacting process. After all, the liquid inside the barrels has to stay put in order to age, sometimes upwards of a decade. "The whiskey won’t lie to you," Buckley said. "It’ll stay in or it won’t."

Some of the tools that Buckley learned to use are the same ones — not the same kind, mind you, the exact same ones — that his grandfather used. In his cooperage, Buckley displayed an iron tool with the number "1" that was passed down from his father, used to mark the barrel so coopers could distinguish whose work they were looking at. Other tools were so specific to the trade, like a compass used to measure the circumference of the top of a cask, that coopers had to learn to make the instrument themselves, sometimes requiring making another separate tool. Buckley inherited these tools as other coopers retired, and uses many of them to demonstrate technique. It's an impressive collection — they look like something out of Moby Dick — and it makes his workspace feel like a living museum, loving tribute to the craft.

But now, for the first time in his 39 years at Jameson, Buckley isn't worried that the craft he's worked so hard to hone will die out. Two years ago, the distillery brought on an apprentice. "It's a rare thing that you meet a cooper, and it's rarer still that you meet an apprentice," Buckley said. (Buckley's daughters didn't take a shine to the craft themselves, though he notes that there have also been female coopers over the years.)

The time investment to become a cooper is no small commitment: Four years, with the understanding that you'll stay at the distillery for pretty much the arc of your career. But Buckley has been training an apprentice for the last two years, sending him to various other distilleries to absorb the techniques at cooperages around the world. "And then he'll come back and we show him the proper, Irish way," Buckley laughed. "But it’s a great thing. For the first time I can say, 'I won’t be the last of the coopers.'"

For access to exclusive gear videos, celebrity interviews, and more, subscribe on YouTube!