Some brandies are aged in wooden casks. Old Speckled Hen is available in bottles, cans, casks, and kegs. Angel's Envy finishes its spirits in old port wine casks before bottling. Other spirits and beverages may also be aged in used sherry casks. These indicate that the whisky was aged in two or three types of casks. This vintage is initially matured for 12 years in American white oak ex-bourbon casks. American Rye, a 13-year-old Australia-exclusive blend finished in ex-rye whisky casks. The spirit is then matured in oak casks. Maturing is very important for a good brandy, which is typically aged in oak casks. The spirit is most frequently matured in American oak casks. After two years of aging in oak casks, it can be sold as calvados. The average age of Krug oak casks is 20 years. The Astrum was sealed into American white oak casks in 1966. The term derives from the taxation paid on "tuns" or casks of wine. Traditionally, it is not aged in wooden casks.