Properly controlling the cooking temperature is a critical part of successful outdoor cooking. Pellet smokers, gas grills, and electric smokers/grills all have one thing in common—the ability to easily and automatically control the temperature of the heat.
But, cooking over a traditional charcoal or hardwood fire is still favored by many barbecue lovers. Controlling the temperature of a wood-fire (including charcoal) grill will definitely take some more hands-on effort, but it’s actually easier than many people think. You just have to understand how it works to learn how to really gain control of a wood fire.
In this article, we’ve broken down exactly what you need to know about how to control the temperatures on a charcoal grill (or wood-fire grill) properly and help ensure you end up with a good final result for your grilled food.
Two simple things affect the cooking temperature in a charcoal or wood grill/smoker. First, there is the combustible material (charcoal or wood) that serves as the fuel source. Secondly, there is the flow of oxygen. You control the cooking temperature by controlling one or both of these things.
But it’s important to know how these two things work together to understand how to control them.
Almost every grill and smoker will have two airflow controls/vents: the intake damper and the exhaust damper. The intake damper is the engine that drives the system and brings oxygen into the fire. You’ll find it towards the bottom of the cooker near where the combustible material (charcoal or wood) sits.
The exhaust damper (aka vent, chimney, or flue), which is found at the top of the grill or smoker, has two important jobs. First, it allows the combustion gasses, smoke, and excess heat to be released from the cooker. Secondly, it pulls oxygen into the cooker through the intake damper.
(Exhaust damper on a Weber charcoal grill)
Source: Weber Grills
This pull, which is referred to as draft, is created when hot gasses rise to the exhaust damper trying to escape. As these hot combustion gasses and smoke exit the exhaust damper/chimney, low pressure is created inside the cooker, which then pulls in fresh oxygen through the lower intake vent.
The more airflow there is flowing through the grill, the faster and hotter the combustible material will burn. So, how exactly do you control the heat that is generated from this process?
Both the intake damper and exhaust damper can be adjusted to help raise or lower the temperature of your charcoal or wood-fire grill.
As mentioned above, the fuel source needs oxygen to burn. So, if you totally close off the intake damper, you starve the fire of oxygen and it will go out, even if the exhaust damper is totally open. Alternatively, if you open the intake damper all the way, the grill’s temperature will rise. So, you can largely control the temperature by mainly controlling how open the intake damper is.
But, that doesn’t mean that you totally ignore the exhaust damper. Oxygen can’t sufficiently reach the charcoal/wood if there is no place for the combustion gasses to go. So, that upper damper/vent needs to at least be partially open at all times. This will keep the gasses from smothering the fire and causing it to burn out.
Until you feel that you have really mastered your cooker and can confidently control the temperature (especially in extreme weather, like during the winter), your best bet is to leave the exhaust damper totally open. To practice, you can do some dry runs of your cooker without food. Play with just adjusting the intake vent and try to hit temperatures between 225°F and 375°F.
You don’t want to start adjusting the upper exhaust vent unless you can’t reach and maintain those temperatures by adjusting just the intake vent.
The amount of charcoal or firewood you use will also greatly affect the cooker’s temperature. Too little and your grill won’t get hot enough. Too much and your grill will get too hot too fast and you’ll have a hard time bringing the temperature down.
When using charcoal, use a charcoal chimney to light the coals and make sure to fill it to the same level every time. Using a charcoal chimney will bring your coals to a peak, stable temperature before they go into your grill. And starting with the same number of fully lit coals will enable you to be able to properly and consistently control the temperature.
For charcoal briquets, they should be hot and covered in gray ash before they go into your cooker. For lump charcoal, you should see a mix of white ash and red glowing embers.
If you are using wood logs as your fuel source, it is best to start burning logs on the side and then put the glowing embers into your cooker to be able to properly control the temperature. As you become more experienced, you can start to experiment with unlit logs.
Keep in mind that the lit charcoal or wood’s temperature will slowly decline as they are consumed by combustion.
If you find that much of your charcoal or wood has been burned up, the temperature is starting to decrease, and you need to add more, the best thing is to only add fully lit coals/wood as soon as you notice the temperature dropping. You will need to experiment to learn exactly how much to add.
The problem with solely focusing on adding more lit coals is that you have to watch your grill like a hawk and as soon as you see the grill’s temperature start decreasing, light more coals and wait for them to fully ash over. In most cases, you’ll end up needing to do this multiple times during your cooking session.
Of course, you technically could add unlit coals/wood, but it will produce a lot of excess smoke and as they ignite it will quickly raise the temperature of your grill, leaving you wondering how to cool the temp on your charcoal grill. In all likelihood, you’ll end up needing to lessen the opening of the intake damper as the fresh coals become fully engaged.
When you start with a good amount of coals that are fully lit and steadily burning, it is much easier to control the temperature by using the vents to control the flow of oxygen to the coals. Then you only have one variable to adjust. The fewer variables the better when it comes to trying to control the temperature of your grill.
If you are having a lot of trouble reaching the desired grill temperature and maintaining it, your cooker may have an air leak. Cheap grills or smokers often have lids and doors that do not seal very tightly. This means that extra oxygen can enter through gaps or that heat/combustion is escaping through false “vents”.
To help mitigate this, you can use gaskets or food-safe silicone sealant to seal any gaps that are causing a leak. If you’ve sealed any leaks and are still having a hard time with the temperature, then start experimenting with adjusting the exhaust damper more than the intake damper. Doing so will change the level of suction from the draft caused by the heat.
Source: Z Grills
Using a two-zone grill setup with your charcoal or wood, with a direct heat side and indirect heat side, will greatly help with maintaining a consistent temperature. Doing so gives you even more control over the flow of oxygen, giving you more control of temperature.
A two-zone setup will also give you more flexibility by having multiple temperature zones to move your food around to as needed. For example, you can slow-roast the meat on the indirect heat side and then quickly sear it on the direct heat side just before it is done. Or food that is almost done can rest on the indirect heat side while the rest of your food finishes on the direct heat side.
Check out our article on two-zone cooking for more information on this type of grill setup.
Understanding how to control the temperature on a charcoal grill / smoker (or wood-fire) is not rocket science. It’s just a matter of knowing what affects the temperature and how to control those variables. Hopefully after reading this article, you have a better idea of how to control charcoal grill heat. Cookers can vary significantly in design, so mastering yours will just come down to practice and calibrating the vents and fuel as needed.
Grab a digital thermometer to keep an eye on the grill’s temperature and practice by doing some dry runs without anything in your cooker. Make sure to write down what you are doing so you know what works to help maintain proper temperature in your grill.
Have you been experimenting with temperature control in your charcoal or wood-fire cooker? Do you know of some other tips to share? Leave a comment below and tell us all about it!
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