All About Beer Magazine - Volume 29, Issue 2
May 1, 2008 By

Walking into the brewery at the Glacier Brewhouse in Anchorage, AK, you might think you were in a wine cellar instead. There in one alcove is head brewer Kevin Burton’s “wall of wood”—an impressive row of about 50 oak barrels, all filled with beer. “Everything goes in the barrel,” Burton says, especially his stout, porter, Scotch ale, bock and barley wines. “It’s a lot of work, but it gives you more options with a batch of beer,” he claims.

But why does Burton put his beer into oak barrels? “Well, beer used to be put in them,” he says. “But I really got the idea from wine and spirits—the flavors they get from wood can work in beer, too. And besides,” Burton adds, “it’s a lot more fun than stainless steel!”

It’s true that in the wine business, small oak cooperage is the norm: winemakers age wines, particularly reds, in 50 to 60 gallon oak barrels to improve their flavors. While some of this barrel-aging tradition is as much mystique as method, it’s undeniable that this technique has worked well for centuries.

The same method is used for spirits, particularly whiskey. All bourbon and Scotch is aged in oak barrels, usually made of American oak. Some brands are well known for using barrels that previously held wine, such as The Macallan, whose whisky is matured in sherry barrels, giving it a unique brandy-like taste.

But the question inevitably arises: since beer is so susceptible to bacterial infection, and sanitation is a fundamental part of any brewer’s craft, why put beer into vessels that can’t be sanitized? Why are brewers like Burton returning to old techniques that practically beg for problems?

The answer is that those “problems,” in the hands of a creative brewer, can also be the source of a complex range of beer flavors—startling flavors that are winning over American beer drinkers.

Unlike stainless steel, wood is naturally porous. Just as the slow evaporation and oxidation of wine in barrels can give it more concentration and body, the same can occur in barrel-aged beer. And for those who like sourness or “horse blanket” aromas and tastes in beer, wood is also the perfect medium for bacteria to flourish. The challenge for a brewer is to manage these processes to add a new dimension to their beers.

The History of Beer Barrels

Wooden barrels, usually made of oak, were once the standard container for beer as well as wine in Europe. Craftsmen discovered that because wood was porous, if it could be dried to a low moisture content before the pieces (called staves) were bent around iron hoops over a fire into a barrel shape, adding the liquid inside would cause the wood to swell, effectively sealing it. In such a cylindrical vessel, a great amount of liquid could be stored and also easily rolled about—a significant advantage in shipping and trade. Moreover, such hardwood barrels were very study and resistant to rough handing, unlike wineskins. It’s been said that the wine barrel was the most highly regarded Western invention by the Chinese.

The idea that such a beverage container could positively influence the flavor of its contents, however, was a realization that evolved slowly. According to Pascal Chatonnet, a researcher at the Enology Institute at the University of Bordeaux (The Barrel and the Wine, 1994), it was not until the end of the 17th century in Europe that wood began to be recognized as a major element in the quality of wine. In fact, the biggest use in France of oak prior to that was for shipbuilding, and it was actually the iron industry that first pressured the French government to guarantee a constant supply of wood products from its forests for smelting fires in the 1880s.

In old England, where oak barrels were also commonly used for storing beer, most were lined with pitch to both seal them against leaks and to prevent the wood from harming beer flavor. This was particularly important in shipping, as in the long sea voyages of beers like India pale ale. As in France, it was only later that brewers discovered that the flavor of oak could also enhance the taste of beer.

In Belgium, a crossroads between winemakers in France and the brewers of England and northern Europe, brewers always seemed to have a different take on barrels. Perhaps owing to the Burgundian technique of fermenting wines such as Chardonnay in small wine barrels, Belgians began making their beer this way (larger oak vats had long been in use for both beer and wine). The smaller barrels proved far better at maintaining the wild yeasts and other bacteria that have defined the different Belgian beer styles, without adding much in the way of woody flavors. Rather than protect the beer from these flavors—anathema to most brewers then and since—the use of barrels encouraged it, particularly for the sour lambic beers. Brewers also often added fruit and spices directly to the barrel to encourage further fermentation and flavor development.

A New Use for Bourbon Barrels in America

In America, oak barrels were also the standard beverage container until the late 1800s, when steel kegs and tanks were introduced. It was the spirits industry that first popularized the use of barrels, both for rye whiskey and for rum. To guarantee the health of the American cooperage business, a law was written (which still in force today) that bourbon barrels can be used only once in the production of this unique American whiskey. Many used bourbon barrels were subsequently shipped to Scotland for the production of Scotch whisky, still a common practice.

This wide availability of used bourbon barrels first brought about the barrel-aged beer phenomenon in the United States. Beginning in the early 1990s, brewer Greg Hall of the Goose Island Brewery in Chicago began experimented by adding his imperial stout to used bourbon barrels he purchased from the Jim Beam Distillery in Kentucky. After its initial fermentation in stainless steel, the beer was aged for about 100 days in the barrels. The resulting Bourbon County Stout (11% ABV) picked up vanilla, tannin and burnt wood flavors from the barrels, as well as some residual whiskey notes. This beer was awarded a gold medal for wood- and barrel-aged beer at the World Beer Cup in Seattle in 2006.

Many American breweries are now using bourbon barrels for a variety of beers, mostly porters, stouts, strong ales and barley wines. With their heavy char and the vanillin flavors of American oak, as well as the maple accents and corn-based sweetness of bourbon whisky, these barrels can add additional depth of flavor to many dark beers.

One of the first barrel beers to hit the West Coast craft beer scene was North Coast Anniversary X, named for the brewery’s 10th anniversary in 1999. This was a huge, sweet barleywine-style beer, with lots of raisiny flavor richness from both the complex malt bill, but also the rich maple and vanilla notes of bourbon barrels. Although it has oxidized and faded somewhat in nearly nine years, the beer still packs a punch (10% ABV).

At Deschutes Brewery in Bend, OR, brewers have now produced two vintages of The Abyss, an imperial stout made with both American and Belgian ale yeasts and an addition of licorice and cherry bark chips and partially aged in bourbon barrels. An 11% ABV, it’s giant of a beer—black, very dense and very full on the palate with the taste of roasted malt, licorice, vanilla and wood tannins, and a long, surprisingly smooth finish. This beer won a gold medal at the GABF in 2007.

But bourbon barrels aren’t just used for stouts and barley wines these days. In Stevenson, WA, Walking Man Brewing Co. makes a bourbon barrel-aged version of its Homo Erectus Double IPA called My Old Kentucky Homo. Alan Sprints, owner/brewer at Hair of the Dog in Portland, OR continues to amaze beer lovers with his barrel-aged brews, including super-hoppy Fred from the Wood (aged in new American oak) and Adam from the Wood (bourbon barrels). His legendary Dave was also aged in a bourbon barrel. At 29% ABV, this was probably the strongest beer ever made in the United States, although Sprints used an eisbock freezing technique to produce the higher alcohol.

Rum barrels, which are generally much harder to come by, are the wood of choice for the Captain Lawrence Brewing Co. of Pleasantville, NY and its Smoke from the Oak, a barrel-aged American-style porter. The Draught House Pub & Brewery in Austin, TX makes Rum Barrel Red. Other brewers have used rum-soaked oak chips to flavor their beers, such as Walking Man’s Ho Ho Homo Erectus and a rare cask of Jolly Roger strong ale made by Maritime Pacific Brewing Co. in Seattle.

Wine barrels have also become popular for aging beer. Fish Brewing Co. of Olympia, WA began a barrel program for some of its strongest beers in the late 90s, using a variety of used wine barrels made of various kinds of wood, including French, American and even Hungarian oak. The results were stunning, especially for the 1999 and 2000 Poseidon’s Imperial Stout, a Chateau Latour of a beer. Unfortunately, the brewery later discontinued using barrels because of contamination problems, and now only uses oak chips for its Old Woody strong ale, which won a gold medal at the GABF in 2007.

But the making of barrel-aged beer is not limited to small American craft breweries. Even the largest brewery in the United States, Anheuser–Busch, has produced barrel-aged beer. For the past two years, the company has released Winter’s Cask Bourbon Ale as a winter seasonal brew. This amber beer is aged in bourbon barrels with the addition of vanilla beans to provide even more “oak” character.

Techniques for Wood-aged Beer

Basically, there are two major ways in which wood is used for beer—with barrels or wood chips. Either can be used in both the fermentation and aging of beer. Chips can be added to beer at practically any time as it matures, but they are normally used in the secondary fermentation process. Generally, the longer wood chips remain in the beer, the more pronounced will be their taste, so this has to be carefully monitored by the brewer. Many brewers have used chips in the past: Bert Grant’s Perfect Porter was made with an addition of oak chips, which gave it a strong vanilla (and somewhat woody) taste.

Likewise, Mount Hood Brewing’s flagship Ice Axe IPA uses chips to mimic the process of barrel aging that was no doubt part of the flavor profile of traditional IPAs, gained from their long voyage to India (it’s likely that Acetobacters and Brettanomyces were part of that flavor, too, however).

Brewers usually like used barrels for their beer, since the taste of new oak is often quite aggressive and can easily overwhelm beer (most wine averages 12% ABV and is not as sensitive to “over-oaking”). Vinnie Cilurzo of Russian River Brewing Co. in Santa Rosa, CA uses only used wine barrels he purchases from top-notch local wineries. “I focus on what was in them before and the quality of the wine, “ he says. His beer Temptation, for example, is all put into former Chardonnay barrels.

An exception to the rule is Alan Sprints at Portland, OR’s Hair of the Dog, who always puts some of his beer Fred into new American oak barrels. With its high hop bitterness, this beer can stand up to new oak flavors, Sprints believes.

Barrel Rotation

Winemakers usually rotate their barrels—replacing a portion of old with new, and/or using barrels that have held one type of wine for another, depending on the type of wood and its characteristics. Brewers are learning to do this as well, since a barrel’s ability to influence beer flavor diminishes each time it is used. The most prestigious French chateaux claim to use only new oak for their wines, but the reality is that even “first growth” Bordeaux will rarely stay in new oak for the entire period of its aging (about two years). Usually these wines will be racked off to older, more “neutral” or “passive” barrels at some point before bottling.

Another common practice in the wine world is to employ used Chardonnay or white wine barrels for red wines, since they have not picked up the stronger tannins and pigments that used red barrels have, and may better affect new wine flavor.

Most brewers new to the art don’t seem to rotate barrels much at present—they simply use them once, as in the bourbon business, or kept them indefinitely for the same beers. Cilurzo, however, after using barrels for a given number of “vintages,” turns them into barrels for his Consecration beer, which is spontaneously fermented in the barrel.

Barrel and Oak Cask Fermentation

Inspired by the Burton Union system at Marston’s Brewery in Burton-Upon-Trent, England, the Firestone Walker Brewing Co. of Los Olivos, CA formulated a plan to ferment a portion of its beer in the barrel. Brewmaster Matt Bryinldson uses 40 new American oak barrels from World Cooperage of Lebanon, MO to ferment the brewery’s flagship Double Barrel Ale. Blow-off tubes are attached to the bungholes of the barrels, where the wort is fermented for seven days, and then moved to stainless steel tanks for cold stabilization. The beer is blended with tank-fermented beer to create the final product, 15 to 20 percent of which is barrel-fermented.

Brynildsnon has used this system for ten years, and is a firm believer in it. “The barrels add a lot of character to the beer. With new oak, a profound oak character is imparted on the beer, with fruity notes and some sulfur,” he says. Brynildson says that he tasted other barrel-aged beers, many of which were seriously oxidized, before starting his program. After that experience, he went straight to the winemakers for help in learning how to use oak effectively in fermentation. Now he purges the barrels with CO2 before filling them, and none remain empty more than 24 hours. Each barrel is used about 20 times for fermentation before being rotated out of the system. “The bonus to this [fermentation] program,” says Brynildson, “is that we can’t afford to give space up for cellaring. It’s a huge incentive to get it in barrel.”

For all the oak that it uses, however, Firestone Walker has made only one truly barrel-aged beer so far, its 10th Anniversary Ale, released in October 2006. This hugely complex beer was made with 100 percent oak fermentation, and then aged nine months in barrel. Using a technique usually employed for reserve wines, only 30 barrels from the 80-barrel batch were selected for the beer. Brynildson plans to create a beer “solera” system in the future, similar to that used to make port wine, in order to blend old and new barrel-aged beers.

Meanwhile, at the New Belgium Brewery in Fort Collins, CO, brewmaster Peter Bouckaert both ferments and ages a number of different beers in oak barrels and larger foudres of 60 and 130 hectoliters. Bouckaert, who once worked for the Rodenbach Brewery in Belgium, makers of the classic sour oak-aged ales, began using oak at New Belgium around 1997. He employs only used wine barrels made of French oak, inspecting each one first. “We treat and inoculate barrels depending on their condition of arrival,” Bouckaert says.

Bouckaert uses the wood and the bacteria it harbors to achieve flavor complexity. “I want to create a balance between lactic and acidic, and some of the related esters in the beer,” he explains. New Belgium’s signature barrel-aged product, La Folie, is blended from many barrels and packaged in champagne-style bottles. It is a very complex beer—fruity and sour with a unique champagne-like effervescence, reminiscent of the lambic beers of Belgium.

Bouckaert’s barrel program is only a small part of the brewery’s total production, however, which reached over 300,000 barrels in 2005. “It’s peanuts in terms of the whole product,” he admits.

Barrels vs. Chips

What’s better for beer—barrels or chips? If it’s oak flavor you want in your beer, there’s no faster way to get it than to add oak chips. Because of the greater surface area of the beer exposed to wood in this way, oak chips are much more efficient than a barrel in this respect. They are also considerably cheaper! With the high cost of new wine barrels (currently around $800 for a 225-liter French oak barrel), winemakers have long tried to find substitutes, including chips, shaving and retesting the inside of barrels, and “inner staves”—a framework of new oak pieces inserted into old barrels. However, as winemakers have learned, these short cuts have their disadvantages. Not only is the flavor extraction apt to be harder to monitor (and easier to overdo), but chips and their like also provide nothing in the way of the slow oxidation that barrels do to enhance taste.

This is a crucial point, because wood aging is different from wood flavoring. As beer sits in the barrel, it is slowly exposed to oxygen in the wood as well as woody flavor compounds. This will greatly affect the texture of the beer, its overall intensity and mouthfeel, in a way that adding chips doesn’t.

Vinnie Cilurzo makes only one beer with chips added—every 23rd batch of his strong ale Damnation. He’s careful about how long the chips sit in the beer, however (usually about 10 days). Sometimes, Cilurzo says, he gets used barrels from wineries that have inner staves inside. “They have given us way more oak than we needed,” he claims. Cilurzo also doesn’t use barrels that have been shaved, since the thinner staves create more oxygen diffusion in the beer.

New Beer from Old Barrels

Craft brewing is becoming more sophisticated, and the techniques of wood aging are leading the way. Just as the awareness of Belgian beers rocked the boat in the United States in recent years as to what a beer can be, the techniques of barrel aging and barrel fermentation are also changing the American beer landscape. The renaissance of beer in America began by going backwards—reviving the classic ale styles of England and Europe. Now brewers are carrying the movement on by using these old aging methods for new creative results.

So the next time you walk into a craft brewery and see a row of barrels, it probably won’t be much of a shock at all.