On the heels of dry hopping, imperial hopping and triple imperial hopping, craft is taking a strong right turn to the past. Everyone is lining up for those barrels. Since the mid-‘90s, beer has been straggling back to the wood, but now it’s a procession, resulting in a series of BJCP style definitions: Wood- and Barrel-Aged Beer, Strong Beer, and Sour Beer. Smoke-Flavored Beer moved off to a category of its own.

All draught beer was once conditioned in huge wooden casks. It could be a dangerous business. In 1814 at London’s Mieux Brewery a wooden tun containing 20,000 barrels of porter burst, laying waste to the neighborhood and killing eight people. More sane and traditional sizes for trade were the barrel (36 imperial gallons), the occasional hogshead (54 same) and for more convenient dispense the kilderkin (1/2 barrel). Non-metric (U.S.) containers were slightly smaller, still a source of confusion today.

Steel began replacing wood in the ‘50s; aluminum moved in 10 years later. In the beer world, wood all but disappeared and wood cask-conditioned beer as a style soon followed, victims of pasteurization. If you wanted anything from the wood, it was whisky and wine appropriately aged and subsequently bottled. With craft beer’s resurgence, aging in general and barrel-aging in particular were slow to catch on. We’ve only recently come popularly back to the wood.

Barrel-aging consists of beer held for considerable periods in wooden barrels, then bottled or transferred to kegs and shipped. Factors like wood type, previous contents, time and temperature stored, and presence of yeasts wild or injected, yield a great flavor spectrum. Here’s BJCP’s basic description of a strictly wood-aged beer:

“Entries are aged with the intention of imparting the particularly unique character of the wood and/or what has previously been in the barrel. New wood character is often characterized as a complex blend of vanillin and unique wood character but wood aged is not necessarily synonymous with imparting wood flavors. Used sherry, bourbon, scotch, port, wine and other barrels are often used, imparting complexity and uniqueness to beer.

“Five sub-categories allow for substantial variation: taste signatures of wood are separated from those of sour beer. Wild yeasts residing in a barrel or injected to control sourness or astringency are somewhat unpredictable over time. Blending is a way of achieving a desired taste. Fruited wood-aged beers are also allowed, a throwback to Belgium.”

This is indeed a mouthful and it’s easy to see how barrel-aging is toppling into other categories. This year, for example, brewer Shaun Hill’s Norrebro Barrel Series took three awards at the World Beer Cup in these categories: Barley-Wine Style Ale, American-Style Sour Ale and American-Style Imperial Stout (not as Wood- and Barrel-Aged).

Not only are these multi-varied tastes here to stay, but they provide great price points for brewers, gently offering competition to wine prices. Three big grownups of this movement are Tomme Arthur (Port Brewing/Lost Abbey, San Marcos, CA), Vinnie Cilurzo (Russian River, CA) and Rob Tod (Allagash, Portland, ME). Their big and small offerings are carving a competitive price niche above most of the shelf. Topping my list is Lost Abbey Angel’s Share Grand Cru, a blend of 1-, 2-, 3-, and 4-year-old barrels. The small $40 bottle at Monk’s in Philly was not excessively priced for one of the best beers I’ve ever had. Russian River woos us with French Oak: Temptation, Beatification, Supplication. Allagash proffers Curieux (Bourbon) and Odyssey (New American Medium Toast Oak).

Watch out for these: Scott Vaccaro (Capt. Lawrence, Pleasantville, NY) presents his Smoke From The Oak series (bourbon, wine, rum, apple brandy, port barrels) to further raise the ante. Cigar City’s (Tampa, FL) Capricho Oscuro sleeps in Maker’s Mark barrels; their Humidor Series is aged on cedar. Schlafly (St. Louis, MO) tempts with lip-smacking bourbon barrel Imperial Stout and Missouri Oak Barleywine (both 10%).

Enormous wood foeders at New Belgium (Ft. Collins, CO) keep old world aging and blending of sour beers alive with La Folie and Eric’s Beer; last year Boston Beer installed three foedors in their test brewery, but you have to travel to Boston to buy their triple, red and kriek. Now the Belgians are imitating us. At the Pre-Zythos Festival in March, six featured European brewers poured nearly everything out of scotch, brandy, wine and other assorted barrels to a boisterous, eager crowd. Podge’s Oak Aged Imperial Stout (10.5%) was mellowed and thirstily oak dried.

To highlight the penetration of barrel-aging, consider the Craft Brewers Conference 2010 in Chicago. Local Illinois Craft Brewers Guild breweries came together to make the 2010 Symposium Ale at Goose Island Wrigleyville. Named Heartwood, it’s a blend of Bourbon County Stout, scotch ale, barleywine and imperial IPA. All four beers were aged in Woodford Reserve barrels, then blended together and bottled. Each conference attendee received a bottle.

Goose Island followed up on this with a brewery open house featuring a dessert line of Greg Hall’s ubiquitous Bourbon County Stouts with delights such as BC Pappy Van Winkle Barrel-Aged and Bourbon County Coffee served with chocolate desserts. On the near northside Rock Bottom Chicago featured a totally different Redline Russian Imperial Stout (Heaven Hill Barrel).

The list goes on and on. Nearly every brewer that can latch onto a barrel or three has a batch wood-conditioning as you read this. This reviewer is observing less of a trend and more of a positive return towards whence we came.

One question though. With all those empty barrels rolling into breweries, who the hell is drinking all that bourbon?