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.
