I've only had one bottle of Innis & Gunn before, and that was their flagship oak aged ale, Innis & Gunn Original. I think I enjoyed it at the time, though it may be time for a reappraisal. Also, I've heard good things about their Rum Cask matured beer, so further exploration into the range may be warranted.
This is their limited edition stout aged in whiskey casks from 'a famous Irish distillery'. Hmm.
Innis & Gunn Irish Whiskey Cask pours pitch black motor-oil colour with a small off-white bubbly head. The first thing I notice about the aroma is that it really is exceptionally fruity. Belgian Quad-like fizzy sugary dark fruits dominate the nose, with deep and warm malt notes underneath. In fact, the coffee and smoke bitterness I'd normally associate with a stout is very subdued. Milk chocolate and toffee notes develop with time, but ultimately it's the dark, booze-soaked fruit that really stands out in the aroma. This Quadrupel-like fruitiness is in the front of the taste too, but here the woody toffee, warm caramel and chocolate elements come into play a bit more. The finish provides warmth via syrupy alcohol and caramel, and the whole drinking experience is enjoyable.
I must say, I liked this beer much more than I though I would. I can't stress just how much like a Quad it smells (for a stout), and it's definitely the fruitiest stout I've ever tasted. The roasted malt character that usually defines a stout is very muted, but flavour in this beer is otherwise loud, and worth paying attention to.
This beer isn't cheap, and you could spend less on better, but if you've got the dosh, it's worth a go.