From the Brewdog website
Tactical Nuclear Penguin Bottling Note
First released as the world's strongest beer, this is a completely insane product from the equally bonkers chaps at BrewDog. This fantastical quaff is produced using intense cold, utilising a process called "chill and skim" (which hints at how it works!). The result of this is an Imperial Stout that weighs in at a whopping 32% abv. Of course, they didn't stop there. After it was brewed, they popped it into an Arran whisky cask for 8 months, before a further 8 months in a cask from a famous Islay distillery. The result... Tactical Nuclear Penguin - BrewDog's first double-casked beer!
Sink the Bismarck is 41% haven't tried it yet but give me time
I had a couple of crackers in the Dispensary Ratsputin 7.4% Rat Brewery and a 7.2% IPA which for some reason I cant remember its name but it was a bit good