Pre-Columbian Mexico; the word barbacoa is the source of the English word barbecue, passed through Caribbean Spanish. The technique was documented by Spanish chroniclers in the Caribbean and mainland Mexico.
Barbacoa is the ancient Mexican pit-cooking technique — meat (traditionally the whole head of a cow or sheep, including cheeks, tongue, and brain; or lamb shoulder; or goat) is wrapped in maguey leaves (or banana leaves in the tropics), sealed, and slow-cooked in a sealed underground pit over hot coals for 8–12 hours. The resulting meat is extraordinarily tender — beef cheeks cooked for 10 hours become gelatinous and pull apart in fine threads — and the juices that collect in the pit form a concentrated, deeply flavoured consommé (consumed as the first course, before the tacos). The Hidalgo state preparation uses maguey leaves (Agave sp.) to wrap the meat; their chlorophyll and mineral compounds infuse the meat. Commercial barbacoa is now produced in pressure cookers or large pots, but the traditional method remains active in Hidalgo, Mexico State, and Morelos. Beef cheek (cachete) is the most prized cut for barbacoa — its extraordinary collagen content creates a sauce-like texture when fully rendered.
Barbacoa has deep, mineral, smoky flavour from the maguey leaves, extreme richness from the collagen-rendered beef cheeks, and the concentrated umami of the long braise.
Time is the technique — barbacoa cannot be rushed; 8 hours minimum for beef cheeks, 12 for whole heads The maguey leaf wrap contributes mineral character from the plants inulin compounds The collected juices (consommé) are as important as the meat — they must be reserved and served as a drink with the tacos Achiote paste or chile-based adobo is rubbed onto the meat before wrapping
Beef cheeks cooked at 150°C in a covered pot with agave leaves (or banana leaves), beer, dried chiles, and aromatics for 6–8 hours produces excellent barbacoa without a pit Chipotle en adobo (La Costeña brand) rubbed into the cheeks before cooking adds smoke and depth reminiscent of the maguey-pit flavour
Under-cooking — beef cheeks that have not fully rendered their collagen remain tough and fibrous; the texture should be falling apart
Rick Bayless, Mexico One Plate at a Time; Diana Kennedy, The Art of Mexican Cooking