I tried Bison Chocolate Stout a while ago, it's brewed by Bison Brewing Co. in California. I have several bottle mailed out to me from an old friend of mine. I poured the brew into my holy beer mug, and the body was a thick dark brown, with a nice two finger head. Sitting in my mug, it looked like a fine brew. The aroma was full bodied, and gave off chocolate malts, roasted coffee beans, cocoa powder, and possibly some spices. The taste was great, thin in the mouth, smooth down the pipes, with a serious chocolate kick. The chocolate taste take on sort of a burnt dark chocolate style, which I found unique, though very tasty. This blend is certainly one of the more bitter chocolate brews I've tasted. The carbonation was moderate, just about perfect I would say for this specific bottle of it. Overall, I was happy I tried it, and can say it's worthy of a test by anyone. If you like your chocolate more bitter than sweet, this is the blend for you.
