In today's hyperactive cocktail climate, new ideas travel faster than a bottle of Fernet Branca in a room full of mixologists. Case in point: barrel-aged cocktails.

The seed was planted when Portland, Oregon-based bartender Jeffrey Morgenthaler tasted a Manhattan that had been aged five years in a glass vessel by noted London bartender Tony Conigliaro. Back at home in his bar, Clyde Common, he began aging cocktails in barrels instead of bottles to cut down the wait time.

An avid blogger, Morgenthaler quickly posted the results--smooth and nuanced drinks that brought new life to old formulas--and it didn't take long for others to catch on.

Nathan Kinderman, the bar manager at the restaurant Sardine in Madison, Wisconsin, is aging Negronis using locally made Death's Door Gin.

In New York, Greg Seider at Summit Bar plans to put a couple of his original cocktails in barrels, while Tom Chadwick at Dram in Brooklyn may be the first to experiment with an aged Martinez (a variation of the martini, made with gin, sweet vermouth and maraschino liqueur).

Thanks to easy access to mini barrels, it's only a matter of time before the craze hits the home bar. For the experimental set, a few suggestions:

• Stay away from aging whiskey-based drinks in whiskey barrels (too much of a good thing); instead, try Tridents or El Presidentes.

• Stick with spirits-only cocktails: Dairy and fruit juice are not meant for aging (with the surprising exception of eggnog, which Morgenthaler ages in bottles).

• Be patient: Give the contents at least six weeks (for a two-gallon batch) to get optimal results.