From the Morning Advertiser 26.11.09:
'The whopping 32% abv Tactical Nuclear Penguin began life as a 10% imperial stout 18 months ago. It was then aged for 8 months in an Isle of Arran whisky cask and 8 months in an Islay cask, making it the brewer’s first double cask aged beer.
The final stages involved storing the beer at 120 degrees for three weeks to get it to 32% abv. It was put into containers in the cold store of a local ice cream factory where it endured 21 days at penguin temperatures, explained the company'.
I must admit I'm curious to try it.