Prep: 10 mins
| Cook: 1 hour 30 mins
| Extra time: 30 mins, marinating
Pour the beer into a large pot, and stir in the mustard and brown sugar until dissolved. Add the ribs, and bring to a simmer over medium-high heat. Cook 45 minutes.
Drain the ribs in a colander set in the sink. Meanwhile, whisk the ketchup, lemon juice, Worcestershire sauce, and onion together in a large bowl. Season with salt, pepper, and cayenne pepper. Toss the drained ribs with the BBQ sauce, and marinate at least 30 minutes.