When lit charcoal turns grayish white (start checking coals after 15 minutes), the grill will be at its hottest and will then begin to cool off. How long you can hold your hand 5 inches above the grill rack directly over the coals determines the heat of your grill, as follows:
• Hot: 1 to 2 seconds
• Medium Hot: 3 to 4 seconds
• Low: 5 to 6 seconds