Birria was traditionally made with goat meat because goats were considered a nuisance animal by early Spanish colonizers in Jalisco, and stewing them in chiles was a way to make the tough meat edible.
Goat or beef is slow-braised for hours in a deep red chile and spice broth until falling apart, then served either as a stew with a bowl of consomé or shredded into tacos dipped in the fat-red broth. Market stalls in Guadalajara and rural Jalisco towns sell it especially on weekend mornings.