How do you control the heat on a charcoal grill? Despite the volatile nature of a charcoal (or wood) fire, there are four effective ways to control the heat.
Adjust the airflow: Most charcoal grills have vents on the bottom. Open the vents wide and you get more air and thus a hotter fire. Partially close the vents and you get less air and a cooler fire. Make sure the vents are open when you light your charcoal and set up the grill. If you have trouble starting a charcoal grill, the vents may be clogged with ash.
Build a three-zone or two-zone fire: Another way to control the heat is to rake out the coals in varying thicknesses. To build a three-zone fire, arrange a double-thick layer of coals over one-third of the firebox—the third farthest away from you. This will be the hot zone for searing. Rake out the remaining coals in a single layer in the center of the grill; this will be your moderate zone for cooking. Leave the remaining third of the grill fire-free for a cool or safety zone. By moving the food from the hot to the medium to the cool zone and back, you can effectively control the heat over which the food is grilling.
To set up a two-zone fire, rake the coals into an even layer across two-thirds of the grate. This is your grilling area; the coal-free (fire-free) area is your safety zone.
Monitor the distance: The closer you move the food to the fire, the hotter the heat will be and the quicker the food will cook. Some charcoal grills (like front-loaders) have grates you can raise or lower to bring the food closer to or farther away from the fire. If your grill has a fixed grate, you can mound the coals higher toward the back of the grill and control the heat by moving the food closer to or farther way from the fire.
Make a grill shield: If your food starts to cook (or burn) more quickly than you desire, make a grill shield by folding a piece of heavy-duty aluminum foil in thirds, the way you would fold a letter, and sliding the shield under the food. The shield will block the heat, slowing the cooking process. A shield also works well for keeping the exposed ends of bamboo skewers from burning.