How grown-up acorns make fermented corn water taste better
The tabby kitten’s chest expands and contracts. Somehow, it’s latched itself horizontally to the side of a bourbon barrel. It stares intensely at the wood shavings piled on the floor below, then pounces. Of course, Master Cooper Matthew “Choo” Lipsky is immune to the wee beast’s shenanigans, but everyone else in the warehouse observes, bemused, as the cooperage cat battles nothing but rustles in the sawdust.
That sawdust is remnant of the premium white oak to which Lipsky has devoted his craft and trade. Lipsky is a cooper—a barrel maker. His cooperage is located in the type of place Google Maps gets wrong, the industrial sector of an already industrial Indiana city: Fort Wayne.
Few, if any, American coopers make barrels as artistically as Lipsky does. It’s hard enough to generate revenue from artisan spirit barrels, especially when the coopering industry is monopolized by Independent Stave Company, a Missouri-based barrel-popping machine.
But four years ago, in the midst of a perfect economic storm, ISC fell behind, unable to meet the demand of a massive craft distillery boom. Clients were placed on a two-year waiting list for barrels, and prices shot up 150 percent. Since bourbon, by U.S. law, must age in a new charred oak barrel, distillers got creative with how they aged their whiskey or else went out of business altogether. No barrels, no bourbon.
“There were just not enough suppliers of barrels, and there was a crap ton of new distilleries,” Lipsky says. “We have all these new places opening up with the big craft distillery boom, and they’re trying to buy barrels, and there’s only a half a dozen cooperages to buy barrels from in the United States.”
Craft coopers like Lipsky emerged, filling the void. And even though ISC recuperated from its backlog, the economic lapse reminded Americans just how deeply the bourbon industry relies on white oak.
This story begins 85 to 100 years ago. A few hundred white oak acorns collectively sprout from several acres of Midwestern soil. Oak thrives in sunlight, and for some sudden reason—a fire, a mass timber harvest, an abandoned corn field—this patch of earth just opened for business.
Over the next two decades, the white oak trees—species name quercus alba—grow in unison. If they survive the grass, which grows faster than oak and robs the saplings of their sunlight, they’ll endure decapitation at the jaws of deer or fractured root systems at the hooves of cows. If they survive the fauna, then a slow-motion war unfolds as the oak trees joust with their adolescent limbs, battling for natural resources.
This battle is important. Stave wood—the concave slats of wood that make up a barrel—has to be clear of imperfection.
“It cannot have any defects in it; it can’t have any knots,” says Jim Pierce, president of Pierce Lumber Inc. in Belle Plaines, Iowa. “Knots are limbs. That’s what the tree grew from. It’s got to be a clear piece of wood, and the only way you’re going to have a clear piece of wood like that is competition from the trees around it so its sunlight isn’t hitting all sides of it. It’s only coming from the top, so the tree has to grow straight up to be able to get sunlight.”
Three quarters of a century pass by; generations of Midwesterners are born and die, but if all goes well, the white oak remain. Their trunks dilate to around 18 inches; they tower like static giants 100 feet above the plains. If little to no rain falls that season, the oak is ready for harvest.
The taste of a bourbon is a direct function of the chemical composition of the white oak in which it is aged. But unless the tree is cut correctly, the wood may refuse to hold liquid at all.
This is where things get a bit technical. Lumberers like Pierce know oak trees funnel water through two types of ducts: the capillaries, which run from the roots of the tree to the branches, and the medullary rays, which extend radially from the center—or pith—to the bark. That means if a barrel stave is to prevent the liquid from leaking out, the board face must be perpendicular to both the capillaries and the medullary rays. By extent, the log is quarter-sawn (see animation).
“I’m not a biologist, but I know that in red oak, the capillaries are big,” Pierce says. “They’re like straws compared to [those of white oak], which are like filaments of your hair…You can’t make barrels, period—I don’t care what kind of barrel you’re making out of wood. You can’t make it out of any other species. It will leak.”
Hot off the saw mill, the oak is still green, its cells permeated by moisture. The wood is dried either artificially, via a kiln, or naturally, in the open air. The latter is more expensive. But Lipsky, the master cooper at Anne Grey Cooperage, in addition to the distillers that buy his barrels, argue that air-dried, or seasoned, oak produces better whiskey.
“The wood [some distillers] use is very young, and that flavors the whiskey very poorly,” Lipsky says. “It doesn’t just not give it good flavors; it gives it bad flavors. If you taste whiskey that was aged in a barrel where the wood is only a couple of months air-seasoned, it’s going to taste gross.”
So, after about a century, the white oak finds its way to Anne Grey Cooperage, where Dwight, the warehouse kitten, slides underneath the gaylords—basically giant wood pallets—that carry tons of quarter-sawn lumber.
This oak is seasoned three years, some of the most expensive available. Lipsky buys it cheap, though, as scrap wood off another cooperage in Kentucky that makes barrels much larger than his. He and his employees then chop off the defects and use the truncated planks to make smaller barrels.
Once the oak is sorted and cut, it’s shaped into staves—slightly rounded, beveled, cylindrically symmetric strips, 24 of which will annularly line the inside of a primary metal trussing hoop. The wood is then heated, the fibers become pliable, and a secondary trussing hoop forces the stave tops to merge.
Lipsky props the inside of the barrels over an open flame for a very precise number of seconds; the wood chars.
“The char, it’s a filter,” Lipsky says. “When you put stuff through a charcoal filter and it comes out the other side, it doesn’t taste like charcoal. It purifies it.”
Grooves are chiseled at the top and bottom of the barrel to make room for the heads, which Lipsky makes from scratch using machinery he himself engineered. Dwight instinctively avoids interfering with active machines and fire, opting to mingle with the ankles of the warehouse workers when possible.
After that, it’s a matter of aesthetics: capping the barrels, chiseling the bung holes, sanding the wood, placing the finishing bands, and engraving the floral AG logo.
Coopers don’t need to worry so much about leakage in barrels destined to age corn distillate, specifically. Compared to other grain mash bills, corn has quite a lot of sugar.
“From a barrel-maker’s perspective, when you’re putting a spirit in a barrel, the sugar in the spirit helps to swell the grain, and it tends to not leak as much,” Lipsky says. “But if you put a ferment in a barrel, like wine, the grains have to be tighter because there’s less sugar in it and it will tend to leak more.”
Four hundred years ago, Lipsky might have had an apprentice. Coopering was, historically, an indispensable trade, with barrels used everywhere from whaling ships to wineries. But with the rise of plastic containers, the art of barrel making receded to the craft spirits industry.
“Coopering, it’s dead,” Lipsky says frankly.
The barrels themselves, by contrast, are very much alive.
Imagine, if you will, swimming in freshly barreled distillate. It’s dark. Unassailably quiet. Your skin, shrouded in 125-proof fermented corn extract, turns to velvet, and the liquid surface crimps to the beat of the distiller’s footsteps as she walks away and closes the warehouse door.
It’s a hot, mid-summer day in Indiana, so the grain of the oak that surrounds you is maximally expanded. You watch as whiskey molecules push into the walls, past the char, and perfuse the toasted wood. For a moment, all is still.
But as summer fades to fall, you’ll hear the barrel breathe.
Yes. Breathe. Specifically, it will exhale as the temperature descends. And as it does, you see the whiskey molecules reenter the lake of distillate, accompanied by dark red, brown, and black sediment, as well as vanillin, which gives the liquid its flavor. Smoke residue also leaks out.
“If you taste the spirits as they’re aging in the charred oak barrels, that kind of smoky finish shows up in almost all the barrels in about three months or so,” says Derrick Mancini, owner of Quincy Street Distillery in Riverside, Illinois. “And after about a year, it’s gone…This is something that comes from the char, but the process of aging actually removes it again.”
Mancini’s been experimenting with bourbon aging techniques to find the flavor profile described in historical manuscripts. He achieves this by aging his distillate in Minnesota’s Black Swan barrels with honeycomb staves—staves with divots drilled halfway into the barrel to proliferate the distillate’s access to the toasted, vanillin-filled wood.
“The baby bourbon has a darker, redder color, which was described in the early nineteenth century, and it has a smoky finish,” Mancini says.
Quincy Street Distillery isn’t the only establishment getting creative with whiskey aging. Cedar Ridge Distillery of Cedar Rapids, Iowa, tops off the four years in a new charred oak barrel with another few in Spanish Oloroso sherry barrels, or even ex-port barrels.
It just goes to show the bourbon boom isn’t over yet. In 2005, the U.S. harbored less than 100 craft distillers. By the end of 2018, that number reached 1,800. But there are only so many 100-year-old white oaks in the world.
“The big liquor companies are going to buy up all those barrels,” says Chris Diebel, owner of Bubba, a bourbon lounge and restaurant in Des Moines, Iowa. “So, I do think you’re going to start seeing micro distillers getting entrepreneurial and a little bit more creative with the barrels they use…If they can get their hands on wild oak and make barrels themselves, then it parts a different flavor, which is really unusual and unique. Why wouldn’t we want that, as whiskey drinkers, to try something that’s truly unique to one place and one distillery?”
Transitioning to other barrels may be the smart choice, too. Poor forest management and mysteriously sudden deaths plague North American white oak resources. Over 46 years in the lumbering industry, Pierce has noticed a drawn-out attenuation of the species.
“I’m not real optimistic about the long-term prognosis of our oaks in not just Iowa, but anywhere,” Pierce says.
In a few decades, lumberers, coopers, and the Alcohol and Tobacco Tax and Trade Bureau, which controls the legal definition of bourbon, may collectively have to reevaluate that definition and the whiskey trade’s reliance on new charred oak. But for now, these barrels give soul to the spirit.
“There’s always an X-factor,” Lipsky says. “Always. You just can’t predict it. And all of the people that have all the science-y answers for you, who do all the chemical analyses of wood and different, actual data-driven scientific research, they just can’t put their finger on certain properties or certain functions that happen when you put spirits in a barrel. There’s just a magical thing that happens.”