August 31 2012 issue


Send a letter to the Editor

PAGES (69-73) August 31 2012

COVER STORY The Growing Role of Cooperage in Spirits Kara Newman

At the Independent Stave Company in Lebanon, Mo., distiller clients can choose from a wide range of barrels, amplifying vanilla or smoke flavors here, tannic or creamy textures there. Might a similarly barrel-focused menu be on the way for restaurant imbibers? It’s a real possibility: although cask aging has always been a factor in the production of certain spirits, such as whiskey and Cognac, it has lately become as important as any ingredient in making all kinds of liquors. Cooperage is now a topic on which bartenders need to be as well versed as wine directors are. Are you ready to talk wood?


"Sixty to 70 percent of a spirit’s aroma, flavor, and color comes from the barrels," says Brad Boswell, president of the Independent Stave Company. No wonder distillers guard their barrel sources so closely. Darek Bell, owner of Corsair Artisan Distillery in Nashville, Tenn., is remarkably forthcoming about almost every aspect of his unusual beverages—he’ll happily disclose the mash bill for his 12-grain whiskey and minute details about distilling techniques—but he clams up on the subject of barrels. "I need to keep some trade secrets," he explains apologetically.

"You can kill a product with the wrong barrel," insists Alain Royer, a sixth-generation Cognac maker and the vice president of development for Groupe Renaud-Cointreau in France. Among his recent projects, Royer has partnered with Heaven Hill Distilleries in Louisville, Ky., to create a special blend of bourbons that are aged in Cognac barrels.

Boswell, himself a fourth-generation cooper, works with an array of established American whiskey makers—including those under the Beam, Diageo, and Sazerac umbrellas—all of whom have specific barrel requirements to distinguish themselves from the competition. The results are are dutifully replicated year after year "to keep things consistent," says Boswell. "They want the same flavor that will satisfy the customer—sometimes for generations." But he also has newer customers who are eager to experiment with different types of barrels. "They’re young businesses, trying to make their mark and be different," he says. "A great way to do that is to use special oak, special barrels, or unique combinations of woods."

Here are some of the key variables involved in cooperage.

Wood species: Whether for wine or spirits, oak is the undisputed king of barrels: it’s permeable by air, allowing gradual oxidization to occur, yet it’s also watertight, unlike most other woods. Bos-well estimates that at least 95% of all wine and spirits casks in the world are made of French oak, with American oak the next most popular choice—particularly for bourbon and rye. Woods from Eastern Europe or Asia are used by more adventurous distillers. In addition, a small but growing number of spirits makers are utilizing other species, in the form of chips or staves, to "flavor" their distillates; examples include beech, cherry, apple, and the sweet sugar-maple wood found in some Canadian whiskies.

Wood grain: This may seem like a minute detail, but it can have a surprising impact. At the 2010 Tales of the Cocktail conference in New Orleans, Buffalo Trace offered a comparative tasting of whiskeys aged in fine- and wider-grained barrels. The former showed a more-developed caramel character, while the latter had a hotter feel because more liquid had evaporated through the grain, leaving a more concentrated, higher-proof spirit in the barrel.

Barrel size: "Smaller barrels mean more extraction potential," Boswell says, but he adds that there’s more to aging than the development of specific flavors: "It’s also about maturation—the gentle oxidation, the mellowing. A small barrel might yield more oak but has less air space for oxidation, which can throw the spirit out of balance."

Drying and seasoning: Though the process can take months or even years, drying the wood and "seasoning" it—that is, exposing it to the elements—are critical steps in the barrel-shaping process. According to Royer, newly cut oak contains about 70% humidity; this must be reduced to around 15% before barrel making can commence, since damper wood is harder to cut and shape. Slow drying helps coax out spicy, clove-like flavors; furthermore, Boswell notes, the longer the oak is seasoned, the likelier it is that tannins will leach out of the wood. Renaud-Cointreau allows clients to order according to their preferred level of tannins in the finished barrels.

Toasting: The luscious vanilla and caramel flavors so prized in aged spirits are the result of toasting the interior surfaces of the barrels. "When you heat the wood, it releases vanillin, which is like catnip for humans," Boswell quips, echoing a refrain often heard in the spirits business. Adds Royer, "The toasting is absolutely essential. It enhances the wood’s potential to convey flavor to the spirits." He compares toasting wood to toasting bread—the sweeter the desired spirit, the heavier the toast should be. The darkest toasting, called charring, is popular among some bourbon and cult Scotch producers; Ardbeg’s peaty, single-malt Alligator, for instance, is named for the alligator-skin appearance of the old bourbon barrels in which it’s aged. Known as level-four casks, these barrels undergo a toasting process that imparts a unique mix of smoke, caramel, and spice flavors that some liken to barbecue sauce or bacon. As Boswell explains, "There are simple sugars in the wood; when you heat or char it, you caramelize those sugars." The result is "not always sweet, but has weight and creaminess." Royer, on the other hand, is not so fond of the process: "Charring is like ruining toast. When it becomes black, you should throw it away."


The centuries-old process of "cask finishing," in which a spirit is moved from its normal aging container into a different type of barrel to complete its maturation, has become increasingly prevalent in recent years. Since U.S. Alcohol and Tobacco Tax and Trade Bureau regulations dictate that bourbon barrels must be made of new American oak, once-used ("first-fill") barrels—with some of the bourbon deliciously soaked into the wood—are readily available in the marketplace. Matured rum, Cognac, tequila, and other spirits now spend additional months resting in used bourbon barrels, "chasing" the original spirit out of the wood and adding subtle flavor and color.

Market-savvy spirits conglomerates were among the first to revive cask finishing. Now-adays, Glenfiddich and Ardbeg Scotches are aged in rum barrels, Chinaco reposado tequila sees the insides of Scotch barrels, and Citadelle gin even rests in Cognac barrels. Wine barrels are in hot demand as well, with old containers of Sauternes, Sherry, Port, and Cabernet Sauvignon being used for finishing by distillers of Scotch, bourbon, and some tequilas and mezcals.

Still, cask finishing is far from routine in the industry as a whole. "We use the casks when we are looking for something special," explains Laphroaig master distiller and distillery manager John Campbell, who finishes his 25 Year Old Scotch in used Oloroso Sherry barrels.


If all this seems like a lot to take in, consider that "the menu of barrels has extended greatly versus 20 years ago," says Boswell, "just as bourbon options have expanded." And with increased barrel selection, the mindset of distillers has evolved. In the past, their attitude was "a barrel is a barrel is a barrel," Boswell recalls. Now, they regard barrels "more like fine ingredients and less like mere containers."

Consumers are also more sophisticated than ever before. As a result, both producers and those who sell aged spirits have had to raise their game. "The more you know about the oak barrels, the better job you can do of making good, sound suggestions," says Boswell, who regularly leads tours for the trade.

Even if it seems unlikely that your restaurant guests will soon be quizzing you about wood grains or char levels, there’s no doubt that casks provide not only a great source of flavors, but also an opportunity to discuss how spirits are made. "Consumers like the idea of barrel craftsmanship; it’s very Old World," Boswell concludes. "I think sommeliers would be surprised at how interested consumers are. They have tons of questions."

Download the PDF