Barrel Like with other spirits, longer aging results in a more pronounced flavor. Traditional balsamic vinegar is aged in a series of wooden barrels. Since its invention in 1868, the pepper mash used to make Tabasco sauce is aged for three years in previously used oak whisky barrels. Beers are sometimes aged in barrels which were previously used for maturing wines or spirits. This is most common in darker beers such as stout, which is sometimes aged in oak barrels identical to those used for whisky. Whisky distiller Jameson notably purchases barrels used by Franciscan Well brewery for their Shandon Stout
Bourbon whiskey oak containers for aging. In practice, these containers are generally barrels made from American white oak. The spirit gains its color and much of its flavor from the caramelized sugars and vanillins in the charred wood. Straight bourbon must be aged at least two years, and blended bourbon must contain at least 51% straight bourbon on a proof gallon basis (i.e., most of the alcohol in the blend must be from straight bourbon). The remainder of the spirits in a blended bourbon may be neutral grain spirits that are not aged at all. If a product is labeled merely as