The trick to making a good beef bone broth is to roast the bones before simmering them in a pot of water, herbs, and vegetables. Roasting helps to release a significant amount of fat from the bones, which can otherwise leave a greasy film in the broth or infuse it with an odd, flat, and almost acrid flavor. With much of the fat released and a rounder, more complex flavor developed during roasting, the resulting broth has the flavorful complexity of roast beef.