I have vivid memories of serving a barleywine aged in a bourbon barrel to dinner guests. After the first sip, they stared at me wide-eyed. “This is the best beer I’ve ever had in my life,” sincerely pronounced one guest, an ex-bartender who has tasted a few beers in his time. They each left cradling a gift bottle of the barleywine like they had been presented with the Holy Grail. Talk about validation!

John Moore of Barley John’s Brewpub in New Brighton, Minnesota, credits barrel brewing with putting him on the map when his Dark Knight barleywine scored a 100 on the ratebeer.com site. “I’ve had people call from as far away as France about getting shipments of our barrel-aged beer,” he says. “Our first bourbon-barrel beer lasted six months on tap. Now, it’s hard to keep up with the demand, and we’re going through more barrels than ever before.”

About five years ago, Todd Ashman, then a brewer at a small brewpub south of Chicago called Flossmoor Station, supplied a bourbon-barrel-aged blend of barleywine and brown ale called Train Wreck O’ Flavors to a beer tasting conducted by beer writer Stephen Beaumont. The tasting pitted upstart American beers against classics like J.W. Lee’s Harvest Ale. Ashman’s beer fared so well he ended up being featured in a Wall Street Journal article on extreme beers.

“There’s no doubt that barrel-aging can get you attention,” says Ashman, now sales coordinator and staff brewmaster of Brewers Supply Group.

Not surprisingly, barrel brewing has gone mainstream. Wood and Barrel-Aged Beer was the second most-entered category at the 2005 Great American Beer Festival (GABF) with 75 entries. It is fairly common now to find a bourbon-barrel-aged offering at a brewpub. And more and more homebrewers are forming groups to brew 55 gallons (208 L) of beer for barrel aging – which only makes sense considering that adventurous homebrewers were among the first to experiment with bourbon-barrel aging. It was in the early 1990s when Ashman heard about Chicago-area homebrewers holding “brew ins” to ferment homebrew in bourbon barrels. Chicago’s Goose Island Beer Company began to make commercial beer in bourbon barrels, shortly followed by Ashman at Flossmoor Station. When Goose Island entered a bourbon barrel brew in the GABF in 1995, the judges loved it but had no idea how to categorize it. They decided to award it an honorable mention, anyway.

Barrel brews then moved into the GABF experimental category, but were so popular by 1999 that they no longer qualified as experimental. By 2002, the GABF viewed barrel brewing as “sustainable” and opened a new category: Wood and Barrel-Aged Beer.

“Now loads of breweries and brewpubs are doing this, and the beers are getting more creative,” says Ashman, who is one of the founders of the annual Festival of Barrel-Aged Beer in Chicago.

It is not that difficult for homebrewers to get into barrel brewing. In fact, you just might just find it the most rewarding experience you’ve had in homebrewing. I did. Here are some simple tips to keep it a rewarding experience. We’ll start by looking at bourbon barrels, then get into wine barrel use and the rising interest in using barrels for “wild brews,” a term Jeff Sparrow popularized in his book of the same name.

Anatomy of a Barrel

Before you roll out the barrel, you should know its anatomy. All the different parts of a barrel, and their interfaces, have a name.

The two ends of a barrel are called heads. The curved pieces of wood that connect the heads are called staves and the metal straps around the barrel are called hoops. The place where one stave meets another is called a joint. (The place where one head piece meets another is a head joint.) The circular groove where the flat head pieces meet the round “hood” around the head is called the croze. (The tool that the barrel-maker, or cooper, uses to make this groove is also called a croze.) When the barrel contains liquid, the wood swells and the joints become water-tight. (Barrels that have dried out may leak when first filled with liquid. Adding hot water is a quick way to get the wood to swell.) When some of the liquid evaporates from a barrel, the resulting headspace is called the ullage. The bulging middle portion of the barrel is called the bilge. In the middle of the bilge is a hole in the barrel called the bung hole, which can be “corked” with a bung.

Most barrels used in the production of alcoholic beverages are made of oak. Bourbon barrels are made from American oak. French oak is preferred by many winemakers, but some — lead by the Australians — have started using American oak. Barrels are toasted, or charred, inside to varying degrees.

Finding the Barrel

Barrels are easy to obtain, but not any barrel will do. (See the sidebar on barrel sources on page 51.) You want a freshly dumped barrel that still smells sweetly of bourbon. If the barrel has an off aroma or the bourbon smell is faint, don’t waste your time.

At the 2003 American Homebrewers Association convention in Chicago, every attendee was presented with a commemorative bottle of bourbon-barrel Russian imperial stout. They were all sour. The brewers had used a barrel that had sat for nine months at a local pub. Once the alcohol dried from the wood, lactic acid bacteria flourished.

The bourbon in the wood is your friend. About one gallon (3.8 L) of bourbon will be soaked into the wood of a freshly dumped bourbon barrel. No beer-souring microorganisms can live in wood saturated with 80-proof alcohol. So get a fresh barrel and do not rinse it. To keep the barrel fresh until you’re ready to fill it, pour in a quart or two (1–2 L) of whiskey and roll the barrel around about three times a week. Alternate which head you stand it on.

Bourbon barrels are relatively cheap, but the cost of shipping may be two to three times the barrel cost. When you call a supplier like Jack Daniels’ Lynchburg General Store, emphasize that you need a freshly dumped barrel for a brewing project. Ask if “No. 1 Selects” are available. If you can supply a commercial address with a loading dock, like your local homebrew store, you will save on shipping. You can order and take delivery of a barrel in about a week.

Bourbon barrels are very economical for a group of 10 or 11 brewers. Figure each individual will pay about $13 to cover the barrel and shipping. Once you get the barrel, pop out the plastic plug that should have been placed in the bunghole immediately after dumping. If you’re not adding beer soon, pour in the sanitizing whiskey and use a number 10.5 rubber stopper as a bung. Keep the barrel indoors, out of sunlight and away from any fumes that could enter the wood. When you’re ready to fill the barrel, dump out any whiskey that hasn’t seeped into the wood. (Don’t throw it out; drink it!)

Why not save all the bother and simply fortify the beer with bourbon? “You want those rich vanilla and coconut-like flavors that the oak can provide,” Ashman says. “Beers that are fortified — the fake bourbon-barrel beers — really show that chemistry. I can pick them up from a mile away.”

Beers for Barrels

When it comes to bourbon-barrel brewing, think big. “You need big beers to stand up to the flavor of bourbon and wood,” advises Moore. “I think barrel brewing has changed the brewpub industry. Four or five years ago, brewpubs weren’t making a lot of big beers except for Belgians. Today, there’s been an explosion of big beers, and I think barrel brewing has been part of that.” The usual suspects for barrel aging are barleywine and Russian imperial stout. Imperial porters and imperial brown ales also are popular. “Higher gravity and darker beers tend to work better,” Ashman says. “The stronger beers allow for longer aging, which allows more complex effects from the wood.”

Part of the fun of barrel projects is sampling commercial beers doctored with a few drops of bourbon. The testing might knock out seemingly logical candidates like an imperial IPA. Bourbon absolutely kills hops, so it is a struggle to get a pronounced hop bitterness and nose from beer aged in a fresh bourbon barrel.

Commercial as well as amateur brewers are getting more adventurous in the brews they select for the barrels. Meads, ciders, historical beers, Belgians and fruit beers have all been tried with some success.

Almost all these beers are high gravity — starting from at least 15.5 °Plato (specific gravity 1.065), according to Ashman. The rule of thumb is to age the beer one month for every percentage point of alcohol. It takes at least four to six months to start to get a complex wood character in the beer, so beers of 9 to 12% alcohol, or even higher, are promising barrel candidates.

Today, most barrel brewers these days use the barrel for tertiary conditioning. So the beer has already gone through primary and secondary fermentation prior to going into the barrel. The barrel is for extended aging. Filling and Aging To fill, barrels need to be horizontal with the bung pointing up. Making a stand can be as simple as two 4 X 4s with a 2 X 4 chock on each side of the barrel. Or if woodworking appeals to you, make your own stand. Our group made one of hand-hewn oak with “Fellowship of the Barrel” carved into the wood. Purge the barrel with carbon dioxide (CO2), then fill it by racking beer from carboys on a high table, or simply force the beer with CO2 from Cornelius kegs. However, you must make sure that the beer filling the cask isn’t contaminated. Every beer going into the barrel should be tasted. Our group has a “rule of two.” If two of the 11 members feel that the beer is contaminated — or simply too poor an example to mix with the others — they have veto rights. We never employed this rule, but we should have — once. We now have a barrel-aged imperial porter with the distinct taste of the wild yeast Brettanomyces.

Most of us like the beer, but we didn’t set out to give it a sour character. After the problem was detected, several members admitted that they caught a hint of Brett in one of the batches, but they didn’t want to be a bad guy and call for its exclusion. Anyone saving the group from sour beer deserves congratulations. On the other hand, barrel brewing is very forgiving to beers with style flaws. If the beer isn’t contaminated and is reasonably close to style, it’s generally fine for the barrel. The mixing, the bourbon and the wood-aging does wonders to bring the various contributions together into a harmonious whole.

Our group likes to collect a one-cup sample of each brewer’s beer into a one-gallon jug and set it aside so we can get an idea of the mixed beer without barrel aging. It’s just one more activity to make these projects fun.

Groups make sense for barrel brewing because you will need a good 60 gallons (227 L) of beer to adequately fill and top-off a 53-gallon (201-L) bourbon cask. Group dynamics in a barrel-brewing project can be incredibly rewarding — or an incredible pain. Recruit members as much for compatibility as for brewing skills. If people get along, the greatest reward of these projects is the personal interaction of discussing which style to brew, developing a recipe and turning out for the big filling and emptying events. If you’re lucky, the beer is just a bonus.

After fitting an airlock into a drilled 10.5 bung, let the beer sit for months. Impatient brewers who remove the beer from the cask after only a few weeks or months are missing much of the wood-aged flavor. The barrel will evaporate 3 to 7 gallons (11–26 L) a year, so keep an extra keg handy for topping off. At the same time you top off, use a wine thief to take a sample and see how the beer is doing.

Oxidation can be a concern in barrel brewing because wood is porous to oxygen. Keeping the barrel topped off helps avoid oxidation — and the dry wood in the head space that can nurture souring microorganisms. If you’re short of beer, flooding the head space with CO2 can help for awhile — before the gas is absorbed by the beer. If you can find it, argon is a heavy gas that will provide the best oxygen barrier.

Sophisticated barrel brewers try to subject the barrel to temperature swings of 20 °F (11 °C). Commercial brewers like Ashman roll their barrels into and out of walk-in coolers to achieve the temperature differential.

“As the temperature changes, the liquid expands and contacts, going in and out of the wood,” Ashman says. “You pick up color from the char (the crystallized oak sugars on the burned interior of bourbon barrels) and you get all this flavor. But keep in mind that if you have any Lactobacillus in your beer, warming it above 50 °F (10 °C) will allow the bug to flourish.”

Emptying Day

While removing beer from a barrel too soon is the more common problem, it is possible to “overcook” a barrel brew. “Wood can definitely overwhelm a beer,” Ashman says. “But if you don’t age it long enough, you get more of a fortified beer than barrel-aged — like pouring bourbon into it.

Homebrewers have an advantage over commercial brewers in that they don’t need to rack a beer from a barrel in order to keep bar taps flowing. They can afford to wait that nine months to a year for the wood to do its magic.

When the beer is about 75% of the way to being done, taste it periodically. Use a wine thief for samples, but be sure to top-off with more beer or purge the head space with CO2.

When you are ready to drain the barrel, one option is a pump. But our group and some brewpubs have had great success using CO2 pressure. Simply get a drilled number 10.5 rubber bung and drill a second hole in it. Insert a long racking cane into one hole and a short length of plastic or stainless steel tubing into the other. Through the short tube, pump CO2 at 5 to 10 pounds per square inch (PSI) into the barrel. At this pressure, a firmly pressed bung stays in place just fine.

Beer traveling through the racking cane goes by plastic tubing into a Cornelius keg. You don’t even need to open the kegs. Just pop up the relief valve and use a connector on the keg’s out-post to let beer travel directly into a keg protected by CO2. A bathroom scale can tell you when it’s time to fill the next keg.

With any luck, you are filling your kegs with a distinctive and fantastic example of beer. Toast each other, salute your patience and celebrate a successful project. Barrel emptying day should be a festive event.

Reusing a Barrel

This topic is a bit controversial. “As a purist, I advocate using a bourbon barrel just once,” says Ashman. “Doing 55 gallons (208 L) of high gravity beer that you condition for six or more months is simply too much work and expense to have failures.” Relenting slightly, he allows that re-using a barrel is OK if you don’t run into sour issues.

Moore, on the other hand, has used barrels up to three times. His Dark Knight Returns barleywine was done in the same barrel as the original Dark Knight, using the same recipe. “It’s funny,” he says, “some of my customers will drink only one or the other. The bourbon is stronger in the original Dark Knight, but I think both are good.”

The times that Moore has used a barrel a third time, he gets very little bourbon character but still picks up the vanilla and tannin notes from the wood. It will be more difficult to pick up wood character from a third-use barrel, so choose a huge beer that can be in the barrel for many months.

“If you must re-use a barrel, do more than a simple rinse,” says Ashman. “It’s similar to the problem of trying to sanitize something that’s still dirty.” He suggests filling the barrel with 170 °F (77 °C) water, letting it soak, then rinsing until the water runs clear.

Our group has had success in timing our brews so that we refill the barrel the same day we empty it. In between, we add about 15 gallons (57 L) of boiled water that is still very hot, slosh it around and dump it. It takes some muscle to manipulate a barrel that is 100 lbs. (45 kg) when empty, and be very careful around scalding water.

Another possibility suggested by Moore is to rinse the barrel with cold water, then pour in alcohol, such as a gallon (3.8 L) of bourbon, to use as a sanitizer. Roll the barrel around periodically to soak up the alcohol. After about a month, refill. For longer term storage between batches, you could try some techniques employed at wineries. World Cooperage suggests rinsing and draining until clear, then apply burning sulfur sticks to the drained barrel. Store the barrel in a cool and humid area, then rehydrate it with 3 gallons (11 L) of 180 °F (82 °C) water. Make sure to stand it on each head for three to four hours.

Dry barrels not only breed souring microorganisms, they run the risk of leaky staves or heads. If you are concerned about the barrel drying out or getting moldy, you can rinse the barrel and fill it with water containing two ounces of potassium metabisulfite for every five gallons (2.9 g/L). Change the solution every two months.

These are just a few of the ways to tend to barrels. There is even a commercial product available called Barrel OxyFresh. If you use bourbon barrels multiple times or obtain used wine barrels — with their much lower concentration of alcohol in the wood — you will want to employ some of these cleaning and sanitation techniques.

There is one other alternative —embrace those souring microorganisms and do some wild brewing.

Going for Sour

Peter Bouckaert, Master Brewer at New Belgium Brewing Co., talks of using barrels as a vehicle for “providing oxygen and microorganisms to the beer.” Brewers who enjoy beers such as lambic and Flanders red ales may find that wood barrels provide an ideal environment for these brews.

To quote Jeff Sparrow in his book, “Wild Brews” (2005, Brewers Publica-tions): “The wooden barrel provides beer-souring microorganisms with a place to live and breed. Many of these organisms require at least small amounts of oxygen to live and propagate. Brettanomyces, in particular, ferments better in the presence of oxygen.”

The traditional sour-beer brewers of Belgium age their beers in wooden barrels for two years or even longer.

Tomme Arthur of the award-winning Pizza Port brewpub in California likes bourbon barrels for sour beers. He believes that the char — the wood sugars in the burned interior — provides sugars for the microorganisms, allowing for a prolonged fermentation. But the majority of brewers using barrels for sour beers seem to prefer wine barrels — specifically, used French-oak wine barrels.

New barrels will overwhelm the beer with oak, so a used barrel is the ticket. French oak — which is more porous than American white oak, and also imparts a slightly different wood character — is preferred because they allow more oxygen. Many brewers of sour styles claim wine barrels provide a more mellow character than bourbon barrels.

Vinnie Cilurzo of Russian River Brewing Co. in Santa Rosa, Calif., came out of the wine industry and is rapidly gaining a reputation for his excellent sour beers. For sour beers, he uses wine barrels exclusively. Sour styles are ideal for beer that could stay in the barrel for years. “The Brett is continually fermenting and thus exhausting CO2, which helps protect the beer from too much oxidation,” Cilurzo explains. “A pellicle (yeast film) forms on top of the beer, which also helps protect it from oxidation.” (See the October 2005 issue for clone recipes of Tomme Arthur’s Mo’ Betta Bretta and Vinnie Cilurzo’s Sanctification.)

Patience is even more of a virtue with sour beers. Brettanomyces can take six months to develop flavors, and Lactobacillus and Pediococcus bacteria can take a good nine months before contributing tart and sour character.

Cilurzo offers a few more tips for barrel-aging sour beers: If the beer gets contaminated or ropey in the barrel, don’t worry. It typically passes with time.

Don’t bottle until the gravity is down to a specific gravity of 1.006. Any residual sugars mean that the beer will become over-carbonated in the bottle.

If you use a barrel for sour brews, don’t use it for anything else. It is almost impossible to remove the souring microorganisms from the wood.

Our group took Cilurzo’s advice to heart. When our imperial porter developed a Brett character, we decreed that the barrel would henceforth be used for Flanders red. After a mere six months in the barrel, we already think our Flanders is another prize-winner. But we will be patient. As an avid barrel brewer once told me, “Give it time and the results will be sweet.”

Paul Dienhart has been involved in barrel-brewing projects with members of the Minnesota Homebrewers Associa-tion and the St. Paul Homebrewers. This is his first article for Brew Your Own.

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Sourcing A Barrel

Bourbon barrels  There are a number of online sources for used 53-gallon (201-L) bourbon barrels. But try to get on the phone and talk to a real human being, making it clear that the barrel is for a brewing project, not planters. Be friendly and tell them you need a freshly dumped barrel, preferably a No. 1 Select. Most suppliers will be responsive to this plea.

Suppliers include:
The Lynchburg General Store (Jack Daniels): (931) 759-4200.
KelvinCooperage.com
BluegrassCooperage.com

There are even independent suppliers like Tom Griffin of Madison, Wisconsin. Griffin hauls up premium, 12-year-old bourbon barrels from Kentucky and supplies them to brewpubs around the country. He also sources Scotch and port barrels. You can contact him at: bourbonbarrel@-yahoo.com

If you’re friendly with your local brewpub, it may have a source of barrels. But beware because some brewpubs get free barrels from their liquor suppliers. Liquor distributors don’t tend to have much understanding of brewing, so these “free” barrels can be leaky or far from freshly dumped — not much of a bargain.

Wine barrels 

Most states and provinces have wineries, so your best source to avoid shipping expenses may be calling your local vintner. Our group scored two beautiful 60-gallon (227-L), French-oak barrels from a local winery. The cost ($100 each) was cheaper than mail-order bourbon barrels. Again, it really helps to talk personally to the supplier. Avoid wines that had malolactic fermentations.

Wineries want fresh barrels for their wines. After two to five years, barrels are of little use to wineries unless they are taken apart, scraped and reconditioned. But used barrels work fine for brewers, who don’t want the heavy oak character of fresh barrels. Wine barrels are preferred for sour beers, but you can use them for other styles if you’re careful about sanitation.

Remember, the alcohol in the wood is less potent than bourbon barrels. Burning sulfur sticks, citric acid rinses and other techniques are needed. The winery should perform the initial sanitation procedure.

Other sources for wine barrels:
• Worldcooperage.com
• nwcooperage.com
• BarrelsUnlimited.com
• 1000oaksbarrel.com
• TheBarrelmill.com

Fellowship of the Barrel Barleywine
(5.5 gallons/21 L, all-grain)
OG = 1.104  FG = 1.026

Eleven Minnesota brewers formed “The Fellowship of the Barrel” to fill a used Jack Daniels barrel with this barleywine. This beer took gold in every regional contest we entered, including the Dixie Cup, and took a bronze medal in AHA Nationals in 2005. The recipe was developed by Steve Piatz, Brew Your Own contributor and BJCP Grand Master II judge.

Ingredients

12 lbs. (5.4 kg) American 2-row malt
1.0 lb. (0.45 kg) crystal malt (10 °L)
2.5 lbs. (1.1 kg) Belgian aromatic malt
0.75 lbs. (0.34 kg) wheat malt
0.25 lbs. (0.11 kg) black patent malt
3.0 lbs. (1.4 kg) liquid light malt extract
3.3 lbs. (1.5 kg) honey
34 AAU Willamette whole hops (90 mins)
    (7.5 oz./ 213 g of 4.5% alpha acids)
1 oz. (28 g) Willamette hops (20 mins)
1 oz. (28 g) Willamette hops (15 mins)
1 oz. (28 g) Willamette hops (10 mins)
1 oz. (28 g) Willamette hops (5 mins)
2 oz. (57 g) Willamette hops (0 mins)
2 oz. (57 g) Fuggles hops (dry hop)
White Labs WLP007 (Dry English Ale) yeast

Step by Step

Mash at 152 °F (67 °C) for one hour. Add malt extract and honey in last 15 minutes, dissolving it in hot wort before adding it back to the kettle. Add rehydrated Irish moss for last 15 minutes. After nine months in the bourbon barrel, keg it and dry hop with 2 oz. (57 g) of Fuggles hops.