Monitoring and Controlling your BBQ Temperature

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Now that you have mastered the various heat zone setups we discussed in the first article (if you have no idea what I’m talking about, you might want to check out this page), the next step is to learn how to control the temperature of your BBQ.

Choosing the right heat zone setup and dialling in the correct temperature are the two fundamental skills involved with cooking great food on your BBQ. It’s not easy, but it’s also not as difficult as you might think.

By the end of this article, you will know how to monitor the temperature of your BBQ and how to dial in and maintain your desired temperature – lets go!

Why is it important to monitor the temperature of your BBQ?

Different foods will cook at different recommended temperatures, similar to how you cook in a conventional oven. An oven includes a thermostat which will monitor the ambient temperature inside the oven and adjust the heat accordingly. Whilst similar devices are available for BBQ’s, most of this is done manually when you are starting out.

If a recipe states that your BBQ temperature should be at 180C, unless you have some way of reading the ambient temperature, you will simply be guessing what the temperature actually is.

I like to think of it this way.

If I asked you to drive a car at 40mph but disconnected the speedometer, you would struggle to maintain a constant speed. There is a good chance you would be second guessing yourself and constantly speeding up or slowing down to what you thought was the target speed.

Add the speedometer back into the equation and now you know exactly what speed you are doing and it is simple to make small adjustments to stay at that constant speed.

The same rules apply to your BBQ. In order to be able to achieve a target temperature and maintain it, we need to know what the temperature is inside your BBQ. There are a couple of ways to do this.

Hood Thermometers

Most BBQ’s today will include some form of thermometer to monitor the ambient temperature inside your BBQ. When you are starting out, they are a great way to tell if your BBQ is at the desired temperature however they are not without their flaws.

Depending on the quality of your BBQ, there can sometimes be a dramatic difference between the reading on your hood thermometer and the actual temperature at grill level where your food is cooking.

The placement of the hood thermometer can also be an issue. On a BBQ like a Weber Kettle, the thermometer is placed at the opposite side of the lid to the top air vents. If you are cooking using an indirect heat set up, the vents should be placed above your food to draw heat and smoke from the charcoal, over your food and out the vent. This means that the hood thermometer will be placed directly over the coals giving you a false reading of the temperature where your food is placed.

As long as you are aware of these differences, you can take them into account when setting up your BBQ to your desired temperature.

But wait! you’ve just gone and splashed out on a shiny new Q and it doesn’t have a hood thermometer – in fact, it doesn’t have any thermometer! Should you just retire it and make it into a fancy herb planter?

No! There are other option available that work just as well – if not better!

The cheapest option is to use an oven thermometer placed on the cooking grate beside the food. This will give you grill level temperature of your BBQ but it has the downside that you have to open the lid to read it – therefore loosing heat.

There is another option that will give you that grill level temperature without having to open the lid.

Grill probes

By far, the easiest and most efficient way to keep track of the temperatures inside your BBQ is using a probe. These have some similarities to an instant read probe however, like the oven thermometer, they can be left in the BBQ for the duration of the cook and will allow you to monitor the temperature from an external unit, allowing you to avoid opening the lid.

There are a number of different probes available with a host of different features. They can be as simple as a single probe, connected to a small unit that sits beside your BBQ and gives you a temperature readout. Some more advanced models will allow you to use multiple probes meaning you can monitor grill temperatures and meat temperatures at the same time. You may also be able to setup alarms that will notify you when your BBQ rises above or drops below a certain temperature range or when your food is ready.

If you want to take things to the next level, you can get a bluetooth or WiFi unit which will transmit your temperature readings to a phone or tablet. In my experience, bluetooth range can be a little poor which is why I now use the ThermaQ Wifi unit which connects to my home wifi allowing me to go anywhere and still be able to check my temps.

Any of the methods above will work just fine – the important thing is that you are using at least one of them to measure the temperature in your BBQ. Now – it’s time to take control of that temperature!

Controlling the temperature of your BBQ

I’m not going to tell you any lies – temperature control terrified me when I first started cooking on a charcoal BBQ. All my past experiences were of a screaming hot BBQ that was burning the very eyebrows from my face as I frantically tried to move my cremated morsels of food around the grill – and now I’m supposed to cook a whole chicken on that!?

To be honest, I wasn’t controlling the temperature – hell, I wasn’t controlling anything! It takes a little practice and some basic understanding of fire but I promise you, if you pay attention to the tips in this section, you will be able to hit a target temperature and control it to keep it exactly where you want it.

First off, lets talk about Gas BBQ’s.

Controlling the temperature on a Gas BBQ

A gas BBQ gives you the ultimate control over temperature as it is similar to the conventional oven in your kitchen. You can easily control the amount of gas being supplied to each burner using the controls on the front of your BBQ and therefore decide how high or low the temperature is. After pre-heating your BBQ, you can adjust the valves up or down to increase or reduce the temperature.

The basic principle of controlling heat is this:

More fuel = More heat

It is really easy to demonstrate this on a gas BBQ. Opening the valve more provides more gas to the burner giving you more heat. Opening the valve less will provide less gas to the burner and therefore less heat.

These same rules apply to a charcoal BBQ. The key to hitting the right temperature is by using the correct amount of fuel.

Controlling the temperature of your Charcoal BBQ

I highly recommend controlling the temperature of your charcoal BBQ using the same principals as a gas BBQ. Adding the right amount of fuel will ultimately lead to the correct temperature.

Before we jump in to how to add the right amount of fuel, I want to share a few tips that will make things a little less intimidating

Hitting the exact temperature isn’t essential

One of the first hurdles I had to overcome was to think of BBQ temperatures in ranges rather than an exact temperature. I wasted a lot of time agonising over getting the temperature to exactly what the recipe stated but the great thing about BBQ is that it isn’t an exact science. Let me give you an example.

If I was setting my BBQ up for low and slow cooking and the recipe stated that I should be cooking at 110 C, I would light the charcoal and bring the BBQ up to temperature. I would adjust the vents, remove a few coals or add a few more until the temperature was exactly 110C. It took a lot of time to get this just right and I now realise that it wasn’t completely necessary. 

Getting your temperature within a range is absolutely fine, the important thing is to maintain a consistent temperature. So if a recipe states 110C, as long as you are in the range of 105C to 120C then you won’t go far wrong.

Allow the temperature to settle before putting your food on the grill.

After you have lit your coals in your chimney starter and poured them into the BBQ, put the lid on and leave the temperature to settle. It can take a little time for the coals to finish lighting and reach their peak temperature. If your temperature is running a little high, you can remove some of the charcoal or adjust your vents a little (which we will discuss later) to even out your temperature. Once your temperature is sitting steady, you can add your food.

Keep a note of how much charcoal you are adding each time you cook and what temperature it resulted in.

You don’t have to count the number of briquettes or weigh your lumpwood but simply keeping a note of ‘½ Chimney starter, ⅓ Chimney starter’ etc and the resulting temperature will allow you to refer back to it at a later date.

So how much fuel should you add to hit specific temperature ranges. I highly suggest you give the video below a watch. In it, I share 7 tips to help you control the temperature of your BBQ, including how to use your chimney starter to measure the amount of fuel for some key temperature zones

As you can see from the video, adding the right amount of fuel is the easiest way to hit your target temperature. While you are learning how to hit those zones, I’d suggest aiming a little lower then adding a little extra fuel to bring you up to your target. If you add too much fuel, it can be more difficult to bring it down to your target.

So now you have your BBQ sitting in the sweet spot, your food is on – how do you maintain that temperature? This is where your vents come in to play.

Maintaining your temperature using your vents

Airflow through your BBQ is important to keep your coals burning and your vents can be used to control the heat being produced by your coals. With the lid closed and both top and bottom vents fully open, air will be drawn through the bottom vent and exhausted through the top vent creating an airflow through your BBQ.

Closing both vents completely will result in your charcoal extinguishing as you have removed the oxygen supply needed for fire to burn. Using this theory, it is possible to restrict the amount of air flowing through your BBQ by adjusting the top and bottom vents.

I highly recommend adjusting the amount of fuel added to achieve your desired temperature rather than relying on the vents to manage your temperature. Vents are great for fine tuning your temperature and finding the ideal vent setup will allow you to maintain a steady temperature however if you have added too much fuel you will struggle to keep the temperature down using vents alone.

The smallest of adjustments to your vents can have a dramatic impact on the temperature of your BBQ but remember that closing them off too much can result in your coals going out. If you find your temperature is running a little high or is starting to climb, closing the vents by a few millimetres can be enough to steady the temperature. If your temperature is well above your target range, I would remove some of the lit coals to bring it down then fine tune with the vents.

I almost always control my fire using the bottom vent and try to leave the top vent fully open as this is your exhaust. Closing off the bottom vent will restrict the amount of air being supplied to the fire.

The weather can have a huge effect on your BBQ. If it is a windy day, that rush of air through your BBQ will fire up the coals and can cause a spike in temperature. You may find you need to close the bottom vents a little to compensate for this. Alternatively, on a really calm day, all your vents may need to be wide open to provide enough airflow to keep the fire going.

While you are recording the amount of charcoal used in your BBQ journal, make a few notes about the final vent setup used to achieve your temperature. You will then begin to learn your go to vent settings for specific temperature zones.

Fire management can be tricky to master and maintaining a steady temperature for the duration of a long cook is something that will get easier with experience so don’t be disheartened if you struggle the first few times you do it.

Remember that it is easier to add a little charcoal to your BBQ if your temperature is low than to bring down a high temperature. Having the right size of fire at the start will make keeping the temperature consistent a lot easier with your vents.

Now that you are up to speed on managing your fire using the right amount of fuel… you need to decide which fuel you are going to use. Luckily, the next article is all about that very topic

Click here to read about the difference between lumpwood charcoal and briquettes and why fuel choice is so important