The main cause of these charred, acrid-tasting birds is the commercial barbecue sauce that backyard chefs slosh on the chicken. High heat readily burns sugar, a major ingredient of barbecue sauces. These sauces are also liberally flavored with spices that will become bitter when scorched or burned.
Knowledgeable barbecuer will not brush on the sauce until 15 minutes before the chicken has finished cooking. They will also use more time and less heat. If the coals are extremely hot and well packed, the barbecuer par excellence will keep the food 4 to 6 inches above the briquettes. The thicker the food, the greater the distance from the coals and, as a direct result, the longer the cooking period.
** Asian Recipes