This recipe addresses low temperature roasting of a standing rib roast. What may be different about this recipe is that the roast is seared indirectly at the beginning rather than directly at the end of the roasting period.
Let the roast[three ribs from small end] warm 2-3 hours to room temperature. Salt and pepper generously. Apply bacon fat or previously rendered beef fat to both cut ends of the roast. Tie the roast to maintain shape. Place a drip pan below the center of the grate. Set up for high indirect heat from both sides on the 22" Weber. Heat to 400F. Place the roast fat side down, and roast for ten minutes. Turn and roast bone side down for 10 minutes. At this point there will be moderate browning of the fat cap, minimal brown of the cut ends, and at least 1/4 cup of drippings with beef fat in the drip pan. Remove the roast from the grill, put it on a roasting pan and roast bone side down in a conventional oven at 200F. It takes at about three hours for the internal temp. to rise to 120F with the 200 degree oven temperature. Remove the roast and rest it. Because the roasting has been very slow, less than the usual resting is needed because the temperature difference from the edge to the center of the roast is minimal. I rest in a warming oven at 150F. The roast will appear browned as it does when you roast at the usual temp. of 350. The meat, however, is rare from edge to edge with absolutely no grey zone. It retains moisture better than any other technique I have tried.