Preheat the oven 425 degrees F. Place the turkey in a roasting pan. Fold and tuck the wings under the body; tie the legs together with string. Brush the turkey with melted butter. Sprinkle with sage, pepper and salt. Roast 20 minutes. Reduce heat 325 degrees F and roast 2 hours 10 minutes more, basting occasionally with pan juices once they begin to appear, or until temperature on an instant read meat thermometer reaches 180 degrees F when inserted into the deepest part of the thigh. Transfer the turkey to a platter and rest 10-15 minutes before carving. Remove fat from the pan drippings. Add 2 1/4 cups of stock to the pan and bring to boil. In a small bowl, whisk together the remaining stock with the flour until smooth. Whisk into boiling stock and simmer until a thickened gravy forms. Season to taste; serve alongside the carved turkey.