how long it take to cook rib roast on charcoal barbecue
Step 4: When ready to cook, brush and oil the grill grate. Place the roast, fat side up, on the hot grate over the drip pan and cover the grill. Step 5: Grill the roast until cooked to taste, 3 1/2 to 4 hours for a medium-rate roast of this size, figuring on 12 to 14 minutes per pound.(If using a charcoal grill, youâll need to add 10 to 12 fresh coals to each side every hour.esides, you can let a cooked prime-rib roast stand for up to 30 minutes before carving. Indeed, at least 10 to 15 minutes of standing time is recommended to allow the juices to flow from the center of the roast back to the exterior. 1  Yield: 12 to 16 servings. 2  Method: Indirect Grilling.