Cask strength whiskey is simply whiskey that has not been diluted with water before bottling. This means that the alcohol by volume (ABV) will be higher than a regular whiskey, which has been diluted to around 40% ABV. The higher ABV of cask strength whiskey can result in a more intense flavor profile, as well as a higher price tag.
So, if you’re looking for a bolder, more flavorful Irish whiskey, Red Breast whiskey is definitely worth seeking out. Just be prepared for a bit of a sting on the way down!