Although Blackened's unique finishing process, where the finishing barrels are exposed to Metallica's low hertz frequencies, has garnered much attention in discussions of the brand, the quality and caliber of their product cannot be denied. The whiskey is aged for an average of 6.5 years in white American oak before being finished in Madeira casks. The innovative sonic aging technique forces the whiskey and barrel to come into contact more frequently, resulting in a magnificent combination of flavors and a powerful tasting experience.