Prepare your smoker for cooking. Then place the prime rib in the smoker on a flat baking sheet and avoid checking it constantly. The temperature in the smoker should be 200 to 225 degrees F. For prime rib, a finished internal temperature of 130 degrees F. is rare, 140 degrees F. is medium-rare, and 150 degrees F. is medium. The keys to success are lightly smoking with mild wood, such as oak or pecan, in small amounts, using a meat thermometer, and avoiding checking on the roast.
