I'm drinking a Young's Double Choc at this very moment, and it is NOT bitter. But I suspect anything would taste good with a home made reuben.
But as for New Belgium, Colorado is a microbrewing mecca. I'll be there in a week, and have three micros in Summit County I intend to visit.
Just sat down with a homemade Reuben and a 1554 Enlightened Black Ale from New Belgium, the same makers of Fat Tire.
This is darker than a Tire with some chocolate taste. Like Fat Tire this is really smooth and easy to drink. Nowhere near as bitter as say Young's Double Chocolate Stout or Brookln's Chocolate Stout, but has a nice chocolate taste with almost no burn. This is an excellent chill session brew with no hurries to get wasted or get it finished.
The Reuben is good too.
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