Sour! I was a pretty surprised with my first taste, especially considering the bottle description:
A barrel-aged brown ale with spices
See, it says right there -- "brown ale". Don't be fooled, this beer really isn't anything like a traditional brown ale, though it is quite good. Sour nose and base, with a bit of dark fruity sweetness. Subtle spiciness. Overall a very rich, complex flavor, which I enjoyed quite a bit.