Pre-heat oven to 300°F.
Trim excess fat from pork and cut into large pieces to fit in a large Dutch oven.
In a small bowl, combine brown sugar, salt, paprika, garlic powder, onion powder and cumin; combine and season with black pepper.
Rub all over pork and refrigerate over night.
In a large Dutch oven, over medium-high heat, heat oil.
Working in batches, add pork and sear on all sides; spices can burn quickly so don’t let it go for too long.
Pour beer around pork and cover with lid.
Transfer to oven and cook until pork is beginning to turn tender, about 3 hours.
Remove lid and cook until pork is very tender and pulls apart easily with a fork, 1 to 2 hours more.
Remove pork from Dutch oven and let rest while you prepare barbecue sauce.