Grilling with the right level (or levels) of heat is just as important as the way you arrange the coals. Charcoal grilling does not require anything like the precision of baking or candy-making but, then again, trying to grill everything over the same level of heat oversimplifies charcoal grilling and misses big opportunities for superior tastes and textures.
There are really two ways of knowing how hot a charcoal fire is. One is to use the thermometer in the lid of your grill, that is, if your grill has one. If you grill often with indirect heat (barbecued chicken, pork ribs, prime rib), look for a grill with that feature. Otherwise you will be tempted to lift the lid too often, just to see how the coals are doing, and that causes troublesome peaks and valleys in your cooking temperatures.
The Hand Test
The other way to know the heat is to extend your palm over the charcoal at a safe distance. Imagine a soda can is standing on the cooking grate, right over the coals. If your palm was resting on the top of the can, it would be 5 inches from the cooking grate. That’s where you should measure the heat of charcoal. Always pull your hand away from the heat before it hurts, and be sure that nothing flammable, such as a sleeve, is dangling from your arm. If you need to pull your hand away after 2 to 4 seconds, the heat is high. If you need to pull your hand away after 5 to 7 seconds, the heat is medium. If you need to pull your hand away after 8 to 10 seconds, the heat is low.