Put the meat through the coarse blade of a meat grinder. Brown in small batches in the bacon fat in a large skillet over moderately high heat. Transfer the cooked meat to a second large heavy skillet using a slotted spoon. Set aside. Wash the peppers in cold water. Discard the stems and seeds. Tear the peppers into 5 cm pieces. Place the pieces in a small sauce pan with the first measure of (cold) water. Cover. Simmer 20 minutes. Drain, reserving the cooking water. Peel the skin from the peppers. Place in the work bowl of a food processor. Add the reserved water. Puree with short pulses. Mix the pepper puree into the beef. Add the second measure of water. Bring to a boil over high heat. Reduce heat to a slow simmer. Cover. Simmer for 30 minutes. Stir in all the remaining ingredients except the masa harina. Cover. Simmer 45 minutes. Mix in the masa harina. Cover. Reduce heat to the lowest possible. Cook 30 minutes longer, stirring occasionally so that the mixture doesn't stick. If too thick, thin with small amounts of boiling water. Serve.