There are three important variables when grilling: the temperature of the fire, how long the food remains over the fire and how close the food is to the fire. To get the results you want you want to consider these three variables, and you will want to change them as the food cooks.
Sometimes you want a hot fire, sometimes a medium fire and sometimes you want to go low and slow. Then sometimes it’s more complex – you might need a hot area, a medium heat area and a cooler area at different times. This doesn’t necessarily mean that you need a fire with a wide range of temperatures as you can raise the grate, or use a higher grate on grills with a second tier of grates (this is where the distance to the fire comes in.) An Item can be moved from one area to another as it cooks depending on what it needs at any particular stage of cooking.
How about some examples?
First season the chicken breast (with a few exceptions like brined pork, most raw food needs to be salted just before cooking) then oil it so that it will not stick to the grill too much. For some foods that stick very easily you will want to oil the grate as well. Place the chicken breast, skin side down, on the grate over the medium fire. Chicken skin burns easily and so we do not want is too hot. You do not want to move the food too soon after placing it on the grill for two reasons, First, most foods will immediately stick to the grill and then, as the area touching the metal becomes browned, it releases. This is especially important for delicate foods like fish, which tear easily. Second, we want nice “grill marks” so you want to move the presentation side – that is the side that will be up when served – to be grilled in only two positions.
Back to the chicken breast, you will leave it for about two minutes before moving it. If you want to check to see what is happening you can lift one side of the chicken and peek underneath, then laying it back down the same way. After two minutes you should see nice grill marks. Now turn the chicken breast 90 degrees (a quarter of a full turn) and cook it until you have nice marks. This should take less time than the first set of marks because the skin is hotter now. Now oil the top of the breast (spray or brush) and flip it over. You now want to move it back to a cooler area so that the heat can penetrate slowly. It will probably take another 5 to 6 minutes to finish. Now here is the trickiest part – knowing when to take it off the fire.
For many items, especially meats, you must remove the food before it is cooked to the degree you want because, due to “residual heat”, food continues to cook after it has come off the grill. Think of it this way: When you cook something you heat the outside and the heat penetrates to the center, so, suppose you have a steak on the grill over a hot fire and you want it medium rare, which means it needs to be 130 degrees at the center. If you take it off when the center is at 130, the outside will be very hot, and the heat from the outside will continue to move in and raise the temperature above what you want. You have to take it off when the center is about 10 degrees cooler than you want and “rest” it for a while so that the heat can finish penetrating. The bigger the piece of meat, the longer the rest. Another good reason for a rest is that cooking meat releases the juices, and if you cut it while it’s still hot the juices will spurt out, so it’s best to wait to slice meat until the juices have had time to re-absorb.
You want it off the fire to rest when the center is still a bit pink. What, you can’t see into the center! Well, there are a few tests to tell if the breast is almost done. If it is a whole chicken breast with the tender attached you can lift the corner of the tender and peek inside. If it’s just a bit pink, get it off. With flaky fish like bass you can usually separate the musculature and see part way in. Another way is to use a thermometer, which is the only way to tell when cooking something very thick like a double-cut pork chop. Finally, the last resort is to make a cut with a small knife to see what’s happening. This is less that ideal, but better than over cooking the item.
So now you have the breast off the fire. Place it on a plate just off the fire where it can rest for a couple of minutes without cooling too much. Now it’s ready to serve, but there is one thing lest to do – clean the grate with your wire brush so the next chicken breast won’t stick.
Steak: rare or medium rare need high heat all the way, for medium or more done you need to move it to the medium part of the grill. If it is a thick steak and needs to be well done it needs to be moved to the coolest part of the grill.
If the item needs to be cooked all the way through remember: the longer the food needs to cook, the lower the temperature needs to be so the outside doesn’t burn.
Fish: most fish like high heat, and usually cook very quickly. Rare tuna needs very hot fire and very short exposure. Of course a thick piece that needs to be well done will need lower heat, and some oily fish, like bluefish or mackerel, might char over high heat.
Burgers: depending on the thickness, high heat for rare & medium, lower for more done. Although you see cooks doing this all the time, do not press down on the patty as it is cooking. This compacts the meat, making it chewier and this squeezes out juices. Maybe not a lot, but every bit counts. Pressing the meat against the hot grate does speed up the cooking a bit, but is it worth it? (All right, I’ll confess that if some fool wants their burger well done, I’ve put a cast iron skillet on top it, but the fool is asking for a dried out hockey puck anyway.)
Vegetables want moderate heat usually, although sometime you might want a quick sear over high heat if you don’t want the center cooked through, or if it’s already cooked through like slices of pre-cooked sweet potato or winter squash.