How it works Hot direct radiant heat does most of the cooking when food is placed in the direct zone. Direct heating is best for steaks, chops, and burgers. Medium indirect convection heat does most of the cooking when food is placed in the indirect zone. Indirect heating is best for roasting larger cuts like roasts or for long low and slow smoke roasted barbecue like ribs. Where the food contacts the grate, it cooks by conduction producing grill marks. As background for this article, you should first read my article on the thermodynamics of cooking and my article on the meat science.

The importance of 2-zone and indirect grilling

The most important concept an outdoor cook needs to understand is the difference between direct heat and indirect heat. Once you understand the difference, you need to learn to set up your grill for both methods. In fact, a setup that allows you to do both is ideal, and easy.

I know you don't think of your grill this way, but it really is an oven. There are two major differences: (1) Controlling the temperature is not as easy as in your kitchen, (2) the flame in your oven is under a metal plate so the food is not over direct radiant heat.

Temperature control

On many occasions you want to cook hot over direct radiant heat (steaks), but on many other occasions, you want less scorching conditions (roasts).

You need to control the temperature of your outdoor oven because the solids and liquids in the food react differently to different levels of heat. For example, most meats are composed of protein, water, fat, and collagen, and each component starts to change at different temperatures. Fats melt at one temp, and water turns to steam at another, and the Maillard reaction (aka browning of meat) occurs at another. If meat is exposed to very high heat for too long, the proteins get their undies in a bunch and shrink, squeezing out the liquids, and the result is tough dry meat.

It would be nice if you could make your oven hotter or colder rapidly. But that's hard to do, especially if you are cooking with charcoal. Even with a gas or electric cooker, temperatures change slowly because the metal of your cooker absorbs and radiates heat. So it is usually a good idea to setup your cooker, no matter what the energy source, size or shape, no matter what you are cooking, with two temperature zones. Whether you are cooking on an El Cheapo Charcoal Grill from Wally World, a Super Sabre Jet Stainless Steel Gas Grill from William of Napa, or a Texas Tinkermann Hand Welded Iron Tube Competitor on a trailer, most outdoor cooking goes best if you use two temperature zones. We'll call one the direct zone and the other the indirect zone. Moving the food from one zone to the other allows you to control the temperature of your cooking. This is especially handy if you have more than one food cooking at once where the thickness and water content of the two is significantly different so they will cook at different rates.

On a charcoal grill. You can create two zones on a charcoal grill by pushing the coals to one side of the grill. Here's an article that shows you how to set up a charcoal grill for two zone cooking.

On a gas grill. You can create two zones on a gas grill too. Many gas grills have more than one burner. On some units the burners are left-center-right, while others are front-center-rear. Some of the aircraft carrier size units have up to six burners so you can create a gradient of heat from hot on one end to medium in the middle and low on the other end. Here's an article on how to set up a gas grill.

Direct and indirect cooking

When meat sits directly above the heat in the hot zone and cooks by direct radiation it is called direct cooking. When the meat is off to the side or there is a barrier is between the heat and the meat, warm air passes across cool meat, the meat absorbs heat and cooks by convection. That's called indirect cooking. Even if your gas grill has ceramic or lava rock or even steel flavor bars above the flame, that does not make it indirect heat.

Direct cooking is best for meats that you want to serve brown on the surface and medium rare in the middle, like beef steaks. This browning, the maillard reaction, creates great flavor. Indirect cooking is best for cooking more slowly. You can still get great browning, but you can keep the heat down and melt the fat and connective tissue better. Indirect cooking is a great way to tenderize tough cuts. here are several ways to cook indirectly. One word of caution. Even though the food is not directly over the heat, the food closest to the heat will cook faster, so it is a good idea to rotate the food or flip it so it cooks evenly. Indirect cooking is particularly helpful if there is sugar on the food to prevent it from burning.

Add a water pan or two if you are smoke roasting

There's another useful technique. If you are smoke roasting, add a water pan under the meat. Smoke roasting, which is usually done at low temperatures for a long time can dry out the meat, so putting humidity into the atmosphere can help keep the meat moist. In addition, moisture mixes with the combustion gasses from the fire and the wood and creates desirable flavors.

Some smokers, like the Weber Smokey Mountain, come with a water pan. That's it in the picture below on the right just beneath the ham and above the charcoal. Here are some ways to set up for indirect cooking with a water pan..

Offset smokers are designed for indirect cooking and smoking. But they are tricky to operate. They can also be used for direct cooking. Click here to learn how to setup an offset smoker and how to modify them to make them work better.	On a Weber Kettle, push the coals to one side, put a water pan on the other. Put the meat above the water pan, and another water pan above the coals. Follow the same concept on other charcoal grills.	The very popular and inexpensive Weber Smokey Mountain and other "bullet" shaped smokers have a water pan between the coals and the food. Leave it in and you are cooking indirect. Take it out and you are cooking direct. The water pan also adds humidity to the oven and can catch drips for sauce.
The metal insert on the right side of this Weber Kettle grill below is called a Smokenator and it keeps the coals off to one side so, as in the photo, you can put your ribs on other side for low and slow indirect smoke cooking, and you can put a pan of beans under them to catch the drippings. If you have a Weber Kettle, you need one of these for about $50 on Amazon.com. Just click the link above. Man, I wish I had stock in Smokenator.
The gas grill at right is set up with a water pan under the meat for indirect cooking and to collect drippings. The pan is filled with wine, fruit, herbs, onions, and more goodies to make a flavorful stock for gravy. To the left is a small pan with wood chips for smoke. Click here for more on how to make the ultimate smoked turkey, even on a gas grill. Another excellent technique for cooking with indirect heat on a gas grill is to turn off one or more than one burner and placing the food over the burners that are off.

This page was revised 10/22/2009