The Ideal Wood for Whiskey is at Risk.

Jeff Stringer, PhD, chair of the Department of Forestry and Natural Resources at the University of Kentucky, makes it an annual priority to track wood commodities prices. Around 2012, he started noticing a spike in demand for a very particular product: white oak staves, the thin strips of wood that become the building blocks of barrels in which distillers age bourbon, whiskey and other spirits.

In the last decade, as the bourbon and whiskey industry has boomed, so too has the demand for white oak barrels. To qualify as a bourbon, after all, a spirit must be aged in a new, charred oak barrel. White oak is preferred by many distillers for two reasons. One has to do with flavor, the other is more practical: white oak doesn’t leak.

“The barrel provides all the whiskey color and over half the flavor, since the complex sugars in white oak break down over the aging process to allow the whiskey to pick up its sweet caramel flavors,” says Greg Roshkowski, vice president and director of wood planning, procurement and processing for Brown-Forman. “Other hardwoods, including red oak, do not have the tylosis membrane that white oak has, meaning they would leak extensively if you tried to use them for barrels.”

The bourbon industry uses about 10% of the total white oak harvested annually in the United States, Roshkowski estimates.

Aged oak barrels

Brown-Forman uses some 40–50 million board feet, a volume measure for lumber, of white oak each year to produce the roughly 800,000–900,000 barrels needed to house and age batches of Woodford Reserve, Jack Daniel’s, Old Forester and other spirits.

The demand for white oak is equally intense at Buffalo Trace Distillery, where bourbon brands including Buffalo Trace, Blanton’s, W.L. Weller and Van Winkle are produced.

“We are presently building a new warehouse every four months and intend to do so for the foreseeable future,” says Elizabeth Wise, senior vice president of government affairs for Sazerac, the parent company of Buffalo Trace Distillery. “Each warehouse holds 58,000 barrels.”

White oak trees are typically harvested when they’re 80–100 years old. As Stringer and other foresters have known since the 1980s, the problem is that American white oak forests aren’t regenerating very robustly. To ensure a sustainable, long-term supply of white oak, both for the spirits industry and other key sectors that rely on the wood, including flooring and cabinet-making supply chains, something needed to change.

That’s how the White Oak Initiative, launched in 2017, came to be.

Protecting Forests of the Future

Spearheaded by Stringer, along with members of the American Forest Foundation and DendriFund, Brown-Forman’s independent, sustainability-focused foundation, the White Oak Initiative now includes a host of forestry management and spirits industry partners.

Their mission is to help ensure that American white oak forests survive and thrive through targeted forestry management and, when needed, replanting. The initiative currently hosts best practices educational workshops for foresters and landowners. The coursework outlines strategies for selective clearing of competing tree species in the forest, so white oaks can regenerate on their own.

“You have these big white oak trees producing acorns,” says Stringer. “The acorns hit the ground, and the seedlings germinate, but they just can’t grow. There’s too much shade. So, what do you do? You take out that understory of beech and maple to allow light in, and you harvest correctly. It’s all about scientifically proven forest management techniques.”

Stringer and his partner researchers are developing cultivars of white oak that are resistant to insects and other growing challenges and pursuing methods that will improve the yield of stave manufacturers so less wood is wasted in the barrel-making process.

Most bourbon barrels are made by binding roughly 31–33 white oak staves with steel hoops and rivets. The barrels are charred for flavor before they’re filled with spirits. Then, the liquid is aged in the barrels for at least two to four years, though often longer for signature labels, before it’s bottled. By law, barrels can only be used once for bourbon distillation, so Kentucky distillers often ship used barrels nationally and internationally, where they enjoy a second life aging other liquors, including Scotch, tequila and rum, as well as certain wines and even craft beers.

Because of the key role barrels play in bourbon and whiskey production, industry executives realize securing a long-term source of white oak is essential for their products’ future.

“Sazerac and those members of our industry who are also involved in the White Oak Initiative realize the bourbon industry needs to focus on replenishing one of its most important assets for our industry to survive,” says Wise. “The White Oak Initiative is about the long-term sustainability of America’s white oak forests.”

Barbara Hurt, executive director of DendriFund and a fifth-generation Brown family member, agrees. The spirits industry’s embrace of white oak sustainability helps add momentum to a cause that’s bigger than just whiskey.

“We believe that we can only solve the environmental challenges we face with businesses at the table,” says Hurt. “Industry has an important role to play. This initiative seemed like an incredible opportunity to bring a lot of people together that are dependent on white oak.”

There are far-reaching implications.

“It’s not just about bourbon,” she says. “When you’re managing for white oak, you’re actually managing for the health of the full forest ecosystem, which is good for wildlife, it’s good for ecology, and it’s good for our communities.”

Bourbon whiskey distillation equipment