Indirect heat is essential for a moist, evenly cooked turkey. Create two beds of charcoal on opposite sides of the charcoal grate and leave a wide area open in middle. Place the turkey on a roasting rack set inside two large disposable foil pans and place the pan over the wide open area (indirect heat). Close the lid.
Once every hour, add five to eight briquettes to each bed of charcoal. This helps to maintain a fairly even level of heat. Drop the briquettes into the grill gently so they don’t send ashes onto the turkey.
While the grill lid is open, tilt the turkey so that the juices accumulating in the center will pour into the pan and flavor the base of the gravy. Cook the turkey until an instant-read thermometer inserted into the thickest part of the thigh (not touching the bone) registers [conversion imperial="170° to 175°F" metric="75º to 80ºC"]. Transfer the turkey to a platter and let it rest for 20 to 30 minutes (the internal temperature will rise a few degrees during this time).