There are many, many kinds of oak tree—it’s a remarkably widespread and diverse genus. Hundreds of species of this long-lived hardwood grow around the world, but especially in the forests of Asia, Europe, and North America. In the United States alone, there are almost 100 species of oak.
Despite this huge range and diversity, coopers use only a few species of the Quercus genus to make barrels, using lumber from trees grown in relatively small areas.
That’s partly because many species of oak are poorly suited for coopering. Some are simply too short, too thin, or too twisted. Others have pores that are too wide, leading to leakage or an enormous loss to the angels. Still other oak species can be used to make tight barrels, but they’re so full of tannins that a spirit aged in them becomes unpleasant and bitter.
Also, the availability of good lumber supply near traditional spirits and wine production—such as the white oaks of the Ozarks near barrel-hungry bourbon country or the well-tended forests that provide for the French wine industry—has led to limited choice.
However, as new alcohol producers take root outside of these traditional boundaries and craft distillers explore unique flavors and materials, there is renewed interest in other American oaks.
A Nudge from Abroad
Ironically, it was Scotland that first showed the most proclivity to explore North America’s different oak species.
For decades, Scotch producers such as Glenmorangie have looked into swamp, burr, and chinkapin oaks, usually as finishing casks. The swamp-oak releases were particularly popular with drinkers. This makes sense to Don McGinnis, president of McGinnis Wood Products, which supplies many of the casks making their way to Scotland. Swamp oak, McGinnis says, “is the best-flavored wood for Scotch whiskey.”
Some newer distilleries, such as Isle of Raasay, also have used new, charred chinkapin casks for the entire aging process, which they say brings “vibrant dark-fruit flavors” to their whiskey. Well-known American distillers such as Buffalo Trace and Michter’s also have explored various oak species.
One challenge for those exploring these other species of Quercus is that many of the trees have a limited range, and they’re not nearly as abundant as the more commonly harvested American white oak. When it comes to chinkapin and swamp oak, “there’s just not much of it,” McGinnis says. While both trees do have a wide range, they’re a bit pickier in their growing conditions than their more widespread cousin, Q. alba.
Another challenge is that many oak species are easy to mix up. Many people mistake Q. alba for its close relative Q. bicolor—swamp oak—and in many parts of the lumber industry, wood from the two trees is mixed together and treated as the same lumber. Confusing things even further, Q. alba is notoriously prone to hybridizing; it will cross freely with burr, post, and chestnut oaks. Furthermore, McGinnis says, once the wood is cut, “few people can tell the difference between chinkapin and white oak.”
Oregon Oak
Oak confusion is not a problem out West. The only oak that grows in Washington and northern Oregon is Quercus garryana, commonly known as the Oregon or Garry oak.
One of the first people to turn garryana into barrels was Rick DeFerrari of Oregon Barrel Works in McMinnville. Trained in the art of cooperage in France, DeFerrari set up shop to serve the West Coast wine industry, which was thirsty for barrels. He quickly found that his home state’s oak comes with many challenges.
For one thing, unlike the managed forests of France that provide tall, straight trees, the oaks from Oregon’s wilderness are often full of “defects” that make for a challenging barrel operation. “We have to work around any kind of defect; we’re looking for a perfect piece of wood,” DeFerrari says. “So, any knots or anything are going to be reject material, so that means our yield from a tree is going to be much lower than a typical yield with the French or the American oak.”
The wood that remains poses additional challenges. “It’s denser than French or American oak,” he says. “So, as far as our machinery, it eats up saw blades and planer knives.”
Fortunately for distillers, the density of Oregon oak wood is accompanied by a density of flavor.
“It is a very impactful oak,” DeFerrari says. “We’re air-drying the wood at least three years, if not four years, to kind of reduce that impact.” After this extended seasoning period, the flavors are complex and multifaceted. “It’s really high in that spice component—nutmeg, clove, all that good stuff.”
Whiskey producers who use these casks tend to agree. Shane Armstrong, master blender for Westland Distillery in Seattle, has a great deal of experience with garryana and its challenges. “It’s very concentrated,” he says. “If you want to ramp up the intensity of your oak profile, use a Garry oak cask.”
Armstrong describes one of the characteristic features of garryana as a “focused clove note,” along with “an indistinct spice that can go in different directions.” Besides the spice, Armstrong says garryana brings “a signature note that we call ‘Kansas City barbecue’—it has the intense concentration of molasses with the savoriness of tomato.”
Although Deferrari founded Oregon Barrel Works to serve the wine industry, he soon found a growing interest from distillers. “Today,” he says, “we do about 90 percent spirit barrels and 10 percent wine barrels.”
One of the first customers looking for garryana barrels was the late Steve McCarthy, considered the “godfather” of American single-malt whiskey. He wanted the casks for his Oregon Single Malt and began using them in the 1990s. Unlike many producers who use unusual oak for finishing casks, McCarthy aged his from the beginning in Q. garryana.
“Oregon oak is a big, bold flavor,” says Caitlin Bartlemay, head distiller at Portland’s Clear Creek Distillery, owned by Hood River Distillers. Instead of overpowering a delicate spirit, however, that boldness works well with McCarthy’s “heavy and flavorful” peated malt. Bartlemay says these two strong components work together to create “beautiful harmony in the glass between all of these really powerful flavors.”
Complementing Oregon Oak
Other distillers use Oregon oak in smaller doses. Besides Q. garryana casks, Westland’s eponymous Garryana whiskey also gets a variety of other barrels. The most recent edition made particular use of red wine and Pedro Ximénez (or PX) sherry barrels.
The use of these barrels was “sort of the obvious thing,” Armstrong says. “PX is bringing a lot of sweetness that Garry doesn’t have. So, there’s a very simple equation there of why that should work, but there’s also some crossover with the dark fruity notes that are interesting.” This combination certainly appears to have worked; Whisky Advocate ranked this edition of Garryana at No. 3 on its Top 20 List for 2023.
At Clear Creek, Bartlemay says they also like that Oregon oak–PX cask combination, which they use for a six-year version of McCarthy’s. “PX highlights the fruity notes—the dried-fruit notes, your dried apricots, your raisins,” she says.
For a newer release with a different kind of sherry influence, Bartlemay and her team also make use of Oloroso casks for finishing. She says these casks are “a little bit more savory because of those tannic, balsamic, fall-leaf notes.” Distiller Garrett Trotter made his first-ever McCarthy’s blend in 2023; it went on to score 95 points in Whisky Advocate, which Bartlemay proudly notes “is currently the highest-rated American single malt in the history of that publication.”
Worth noting: Last year’s Garryana is among just a few sitting at 94 points.
New Saplings
Considering the kind of success seen by Oregon oak recently, and the continued superlatives for swamp oak and other species of Quercus, increased use of these casks seems likely. There is a growing interest among consumers and excitement among distillers both large and small.
Because of challenges in sourcing wood and building tight barrels, American white oak will remain the leader in the United States by a great margin. Still, the future looks bright for some other American oaks.