Cut alpaca meat in medium size pieces.
Brown onion in 4 tablespoons hot oil, until golden.
Pour beer in a medium size bowl and add red ají paste, garlic, cumin, pepper, oregano, annatto, rosemary and sauteed onions. Place meat in this mixture and leave it overnight.
Drain alpaca pieces and brown them in the skillet at high heat. Return meat to the adobo mixture and cook approximately for 1 hour at low heat.
Serve with cooked or fried yuca or cassava.