Preheat oven to 350° F. Put the oil and bacon in a large casserole and cook until the bacon is crispy. Remove the bacon and set aside. Season the beef with the salt, pepper, and allspice and sear in the bacon drippings and oil until nicely browned, 3 to 4 minutes per side. Remove from casserole and set aside. Brown the onions and garlic in the casserole. Return the beef and bacon to the casserole. Add the tomatoes, beer, sugar, thyme, and rosemary and bring to a simmer. Cover the casserole and place on bottom rack of oven. After 10 minutes, check to make sure it's simmering; turn heat up 25° F if not. Cook until the meat is falling apart, about 2 hours. Add the potatoes and cook until tender, about 30 minutes. Serve hot.