Optional: trim any fat from the short ribs. Season all sides with salt and pepper.
In a large slow cooker, add all the ingredients: short ribs, onions, peppers, garlic, beans, spices, tomatoes, tomato pastes, beer (or 1 cup stock).
Cover and cook on low for 8 hours. Transfer the short ribs to a plate. Shred the meat as chunky or fine as you like. Return to pot.
Serve immediately or to lighten up the richness, chill in the fridge and scoop off any fat that solidifies before reheating.