It is a method of slowly cooking food in a covered grill over a spot where there are no coals. Usually the food is placed on the rack over a drip pan, with coals arranged around the pan.
Indirect grilling is a barbecue cooking technique in which the food is placed to the side of the heat source instead of directly over the flame as is more common. This can be achieved by igniting only some burners on a gas barbecue or by piling coals to one side of a charcoal pit. A drip tray is placed below the food to prevent fat from the food igniting and generating a direct flame. Indirect grilling is designed to cook larger (e.g. pork shoulders, whole chicken) or tougher foods that would burn if cooked using a direct flame. This method of cooking generates a more moderate temperature (about 275-350°F) and allows for an easier introduction of wood smoke for flavoring.
While placing the food to one side of the fire places the food further from the heat source and thus reduces the intensity of the radiation, the food is still exposed to direct radiation from the fire. Other variations of indirect grilling place a physical barrier between the food and the fire. One method is to place a plank or an unperforated tray on the grill as a base upon which to cook. If the plank is made from wood and is soaked before grilling, the wood can then be used to impart flavor to the food. Another method of indirect grilling is to place a physical barrier such as a pizza stone between the fire and the food. The heat rises from the fire around the edges of the barrier and then circulates around the food. Most brands of kamado style outdoor cookers have accessories known as heat deflectors which can be placed above the fire and below the food grate.
In the 1990s it became popular to stand a chicken on an open can of beer or other canned beverage inserted into the cavity when indirect grilling. Some believe that the contents of the can boil and flavor the food with the consequent vapor, however rigorous tests advise skepticism on this point.