It is corn season in Ohio and the vibrant green stalks make for a dazzling display as you drive by, like a kaleidoscope as you pass the rows. Even though it is barely summer, the fields of corn brought up talk of corn mazes. Naturally, this discussion led to us talking about the two-zone fire method in a charcoal grill.
Recently, we have been playing around with different patterns of coals to create different temperatures on the grill. Some of the patterns looked a lot like features of a corn maze, and since an indirect heat zone is perfect for grilling corn, many lovely ears of white, yellow, and bicolor corn were sacrificed (in the most delicious way) as our experiments continued.
We also managed to discover a few things in the process.
First, Ohio corn is excellent on the grill, whether you leave it in the husk or shuck it. Second, playing with coals is a lot more fun when you have high-quality heat-resistant gloves. Finally what we discovered is that a simple kettle-style grill can become immensely versatile using variations of the two-zone method.
What is a Two-Zone Grill Setup?
The two-zone method is one of the more important techniques to learn. When done properly, a two-zone fire lets you cook different types of meat at the same time and gives you the ability to sear and cook without having to change the grill temperature which is very hard with charcoal. If you think about a gas grill with two banks of burners, the two-zone method is the equivalent of using one or two burners on one side of the grill while leaving the others off. The result is a stable temperature on one side and a high temperature on the other.
With charcoal, the most common way to build a two-zone fire is to stack coals on one side of the grill and leave the other bare. This pattern works for cooking hamburgers and hot dogs on high heat, while slow-grilling veggies or slow-cooking steaks on the other side.
Advantages of Two-Zone Cooking
The secret to good barbecue is control. The grill master needs to control the coals' temperatures, the proteins' cooking speed, and the order in which items go on the grill. Controlling the time, the number of flips, and the cooking zones all impact the end results.
Making it easier for grillers to control these aspects is a great skill to pick up, and that is the single biggest advantage of using the two-zone grilling technique. Knowing how to create a two-zone fire for grilling and smoking at the same time gives you control of your charcoal grill.
How to Properly Set Up & Use Two-Zone Grilling
The two-zone method relies on properly lighting charcoal and arranging it in such a way as to create heat on only one side of the grill. You will fill your charcoal chimney starter two-thirds full and light it. After 10 to 20 minutes, the charcoal should be ashy and grey in color.
Gently pour the hot coals into the grill's charcoal grate. A fireplace poker or a small shovel with a flame-resistant handle helps to scoot the coals into the proper area.
The basic method has you create one even layer of charcoal on approximately half of the grill. One variation of this design is to slope all the coals to the side of the grill down to a single layer in the middle. This pattern creates a three-zone fire with very high heat, medium heat, and low heat zones on a kettle grill.
You can still use the bottom vent to raise and lower grill grate temperatures. Although, we have found that in most cases, leaving the bottom vent nearly all the way open works best to create a direct heat side of the grill.
What is the Difference Between Direct and Indirect Heat Cooking?
Direct heat cooks food quickly. It is a dry heat source, so it may overcook thin cuts if they are left on too long. Indirect heat is still quite hot, but it is less than the direct heat side of the grill.
Cooking foods further from the heat source lets them cook slower. This is important for things like boneless chicken strips, vegetables, fish, and thick cuts that cook slowly such as chuck roasts or pork ribs.
The direct heat source is excellent for fatty, fast-cooking items like hamburger patties, flank steak that is being seared, and roasting peppers.
Variations of a Two-Zone Fire on a Charcoal Grill
Once we were satisfied that the two-zone method was easy to set up, we started to see what would happen with different configurations of coals. We also experimented with adding wood chips for extra smoke flavor.
A curved, half-moon shape gave us a larger indirect heat zone and it worked great for smoldering wood chunks to produce a great smoke flavor. Since the majority of the cooking grate was at a low temp, this pattern proved to be one of the best designs for slow-cooking and roasting. It gave us wonderful, tender corn without charring the husk too badly.
Next, we made a ring of coals around the perimeter of the grill. This pattern created a high-heat zone around the sides with a lower heat zone in the middle. We liked this design for quick sear and slow-roasting and it was particularly convenient when grilling some of our homemade sausages. We added a cast iron wood chip box to the center and added oak and pecan chips to punch up the flavor a little and it worked like a charm. Roasting the corn was a bit of a challenge since the ears became clustered in the center of the grill.
Then, we put a water pan on one side, stacked lit coals in the center, and left the other side open. It created a perfect mid-zone and a humid area where we got great results, especially from the sweet white corn. Corn benefits greatly from a humid cooking chamber. This pattern gave us the most control over the way the corn cooked but also took the longest to finish.
Other Benefits of Two-Zone Grilling
Indirect grilling is one of the most ancient cooking methods and is the origin of our modern American barbecue tradition. Indirect cooking with a charcoal grill lets you smoke meat to moist perfection, then quickly reverse-sear to get perfect grill marks. It's the best way to cook thick steaks and to slow-cook whole chicken.
The indirect side functions as a safe zone so that you can keep food that is already cooked warm without it drying out. You won't have to worry about flare-ups like with direct grilling and you can use a water pan to create a stable cooking temperature.
You can create different levels of direct heat cooking by layering charcoal thicker where you want more heat. A thin layer across the entire grate with an area that is raised is even useful for cooking similar items that are different thicknesses. The indirect side allows for slower cooking in this variation.
Time to Experiment
Two-zone grilling with charcoal grills is a fun way to experiment with temperatures and flavors to get unique textures. Combining the benefits of direct cooking with indirect heat gives you control over the speed at which your food cooks.
Adding accessories like a half-moon heat deflector or coal separators makes temperature control of the two heat zones convenient.
Try using wood chunks and a water pan to lock in the desired temperature and use the indirect heat side for slow-roasting while searing a steak on the same grill over the direct zone. Low indirect heat is a great way to keep food hot when cooking outdoors and prevent it from going bad when the cooking time goes long.
Cooking food on a charcoal grill and corn season just seem to go hand-in-hand. There is something about the sweet, grassy smell of roasting corn husk and hot evenings that makes this one of our favorite times of the year. We didn't expect to get lost in a corn maze of two-zone grilling, but we are glad we did.