What does ‘Cask Strength’ mean?
Cask strength is a term used by whiskey producers to describe a whiskey that has not been substantially diluted after its storage in a cask for maturation. The level of alcohol-by-volume strength for a cask-strength whiskey is typically in the range of 52 – 66% ABV.
So ‘Cask Strength’ has become a byword for high alcohol – but it’s also loved by Whiskey connoisseurs as it’s whiskey in its truest, purest state. 
While typical whiskey is diluted with water before bottling, cask-strength whiskey goes straight from the barrel to the bottle, retaining its full strength and natural character. Also referred to as barrel strength or overproof whiskey, cask-strength whiskey can clock in between 50-75% ABV, with the typical dram being 60-65% ABV.
Regular whiskey, on the other hand, is diluted to a standard ABV, usually 40%, to keep each batch consistent. Another clear distinction? Cask-strength whiskey skips out on chill filtering, a mostly cosmetic process which removes chemical compounds after maturation. This means the spirit can get cloudy, but connoisseurs love it for this exact reason: It’s not missing anything.
Since cask-strength whiskey is untouched from barrel to bottle, it retains the full spectrum of flavour compounds it picks up from the wooden cask over time during the maturation process. And since these flavour compounds bind to alcohol, cask-strength whiskey packs more of a flavour punch than its lower-proof counterparts.
For connoisseurs and hardy purists, cask-strength whiskey offers an opportunity to taste the spirit straight from the barrel in its most natural, high-proof form, while maintaining a buttery viscosity from non-chill filtration. It also allows the drinker to play blender by choosing to dilute the untouched dram exactly as they wish when sipping.
As a Curraghmore Legacy member, you will of course get to decide whether you bottle your whiskey at cask strength, or at standard ABV – the choice is yours!
For more information on casks, check out this blog post. For more information on the Curraghmore Legacy Cask Member Programme, click here.
