Place ground beef in a large pan, cover with cold water, and bring to a boil, stirring and breaking up beef with a fork to a fine texture. Slowly boil until meat is thoroughly cooked, about 30 minutes.
Add onions, tomato sauce, vinegar, garlic, Worcestershire sauce, and chocolate. Stir in chili powder, salt, cumin, cinnamon, and cayenne pepper until well mixed. Add cloves, allspice berries, and bay leaf.
Bring to a boil, reduce heat to a simmer, and cook, stirring occasionally, for 3 hours. Add water if necessary to prevent chili from burning.