1/2 pound bacon, chopped
1 large while onion, chopped
1 tablespoon dried Mexican oregano*
1 garlic clove, chopped fine
2 cups dried pinto beans, picked over, soaked in cold water at least 4 hours and up to 12, and drained
1 1/2 quarts water plus additional if necessary
1/2 cup sliced pickled jalapeño chiles
a 12-ounce bottle dark Mexican beer such as Negra Modelo or Dos Equis
2 teaspoons salt plus 1/2 teaspoon if necessary
* available at Mexican markets and some specialty produce markets.