Place meat in freezer until slightly frozen. Cut into 1/4 to 1/2 inch cubes.
In a large skillet over medium heat, brown meat until it turns gray. Stir in onions and garlic. Cook until onions are tender, about 5 to 10 minutes.
Cut up canned tomatoes, reserving juice; combine in a 6 quart cooking pot with tomato sauce, beer, chili powder, oregano, paprika, cumin, brown sugar, beef base, bay leaves, salt, and pepper. Bring to a slow boil over high heat. Add meat mixture, and reduce heat to low. Simmer, uncovered, for 2 to 3 hours.
Mix in pinto beans. Simmer for 1/2 hour longer. Taste, and adjust seasonings if desired.