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
Barrel the much lower cost. Sherry is stored in casks made of North American oak, which is slightly more porous than French or Spanish oak. The casks, or butts, are filled five-sixths full, leaving "the space of two fists" empty at the top to allow flor to develop on top of the wine. Sherry is also commonly swapped between barrels of different ages, a process that is known as Solera. Laws in several jurisdictions require that whisky be aged in wooden barrels. The law in the United States requires that "straight whisky" (with the exception of corn whisky) must be stored