Combine beer with next 3 ingredients in a glass or plastic bowl. Add meat, toss gently, cover and refrigerate for 6 to 12 hours. Remove meat from marinade, reserve marinade. Heat oil in a heavy-duty stockpot over medium-high heat. Add meat and cook until browned evenly. Add onion, carrots and celery. Cook for 3 to 5 minutes. Add potatoes, reserved marinade, diced tomato and broth. Bring to a boil, then reduce heat to low, cover and simmer until meat falls apart when poked with a spoon, about 2 to 3 hours.