With no real regard for proportion, I made a concoction of Guinness, molasses, balsamic vinegar, Worcestershire sauce, mushroom tea and ketchup (Jacques Pepin uses it all the time) poured that over the roast and braised the thing at 320 for 4 hours. It was GLORIOUS. With mushrooms, carrots and onions. Oh. My. God. I threw some chopped parsley on it right before I ate it. That was a nice touch.