A barrel-aged beer is a beer that has been aged for a period of time in a wooden barrel. Typically, these barrels once housed bourbon, whisky, wine, or, to a lesser extent, brandy, sherry, or port.[1][2] There is a particular tradition of barrel ageing beer in Belgium, notably of lambic beers.[3] The first bourbon barrel-aged beers were produced in the United States in the early 1990s.[4]
Beers can be aged in barrels to achieve a variety of effects, such as imparting flavours from the wood (from tannins and lactones) or from the previous contents of the barrels, or causing a Brettanomyces fermentation. Oak remains the wood of choice, but other woods are in use as well. Chestnut, ash, poplar, cedar, acacia, cypress, redwood, pine, and even eucalyptus have been used for barrel-ageing with varying success.[2]
The flavours imparted by oak barrels differ widely depending on the oak species, the growing area, and how the wood has been treated. New oak barrels can be used for ageing beer, but they are not common due to high costs. Some flavours that new oak will contribute are wood, vanilla, dill, spice, and toastiness.[1]
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