It's easy to cook prime rib, or standing rib roast, on a gas grill. Yorkshire pudding and creamy horseradish sauce are traditional accompaniments. Don't buy a boneless roast as the bones add to the flavor and create a natural rack for the ribs to cook on. Look for one with good fat distribution. The fat keeps the meat moist and tender. Invest in an instant read or probe thermometer that will signal you when the meat has reached the right internal temperature.
Things You'll Need
Salt and pepper
Preheat your grill and place a drip pan underneath the center of the grill rack, where the roast will be cooked.
Prepare a dry rub for the roast. A dry rub typically has salt, pepper, paprika or cayenne and herbs that complement the meat like rosemary and thyme. Add garlic powder to your rub, or insert slivers of fresh garlic into small slits in the meat.
Rub the dry mixture over the surface of the meat.
Oil the grate on the grill directly over the drip pan and place the roast on it. Insert a meat thermometer into the thickest part of the roast. Make sure the thermometer isn't touching bone.
Adjust your grill temperature as needed by opening and closing the vents or raising and lowering the flame to keep it at about 325 degrees. If your gas grill doesn't have a temperature dial, use a grill thermometer. Plan to cook the roast for about 12 minutes a pound.
Keep an eye on the meat thermometer so the roast isn't overcooked. Remove the meat from the grill when the internal temperature is about 115 degrees, for rare or 125 degrees for medium.
Let the meat rest, loosely covered with aluminum foil, for 15 minutes for rare and 30 minutes for a more well done roast.
Add water to the drip pan from time to time if you want drippings for gravy or Yorkshire Pudding.
The roast will continue to cook as it sits. Carve it before it's overcooked.