The Bushmills 30 Years American Oak Cask comes from the Causeway Collection. The triple-distilled single malt initially matured for 14 years in ex-Oloroso sherry and ex-bourbon barrels. The whisky then received a 16-year finish in new burnt-out American oak barrels. A total of only 918 bottles in cask strength with 41.8% vol. filled. Cooling filtration and dye were dispensed with.