TABLE OF CONTENTS
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How Your Oven Works
What an Oven Thermometer Does
Types of Oven Thermometers
How to Tell If Your Oven Is Miscalibrated
Bread underbaked? Pizza burned to a crisp? If only determining the temperature in your oven was as easy as pie—then actually baking a pie might be a piece of cake. But getting the oven to the temperature your recipe needs is not as simple as turning it on. The reason? By design, ovens do not maintain constant temperatures—they fluctuate. And speaking of fluctuation: Opening the door to the oven almost instantly causes the temperature to drop and every appliance has hot and cool spots.
So, how can you accurately determine the temperature of your oven? An oven thermometer, a standalone reader that sits in the appliance's cavity, can help. First, however, you need to understand how ovens work—then decide which thermometer is right for you.
How Ovens Work
Ovens' internal thermostats turn the heating element on and off, which is why their temperature fluctuates up and down in cycles—quite like a sine wave, explains Tim Robinson, vice president of marketing at thermometer makers Thermoworks. Suppose you set your oven to 350 degrees: It will maintain that temperature by heating the oven beyond that point (say, to 370 degrees) and then turning off the heating element and letting the oven cool—to around 330 degrees—before turning on the heating element again to re-start the cycle, he says.
The built-in gauge for most ovens won't display the accurate, moment-by-moment temperature, which is where oven thermometers come in. That's also their caveat: Most of these devices only read the oven's current temperature—and since that number changes based on where the oven is in its heating and cooling cycle, you ideally need a device that can average the highest and lowest (more on that later!).
Why You Need an Oven Thermometer
When you cook a roast, the most efficient way to tell if it has reached the required temperature is to insert a probe thermometer into the meat. Baking (or cooking anything besides meat, for that matter) is different. You need to know the precise temperature of the oven, not the internal temperature of the bread, pie, or cake you are baking. Using an oven thermometer to understand the actual performance of your oven allows you to bake more precisely and consistently.
Types of Oven Thermometers—Including Which Are Best
Now that you understand why an oven thermometer is an essential tool in your baking arsenal, we're here to tell you that not all oven thermometers are the same. Some are much easier to use and more accurate (and know how to get that "average" temperature!) to boot.
Most Accurate: Square Dot Oven Alarm Thermometer
The Square DOT oven alarm thermometer, released last year, was built specifically to gauge both your oven's average temperature and the temperature of what you are cooking. It has a built-in averaging function that reads the temperature of the oven every second for 15 minutes on a rolling basis (dropping the oldest recorded temperature to make room for a new temperature reading each second). The device then averages those 900 temperatures (yes, 900!) to reveal the true average temperature of your oven.
The reason why this level of accuracy is key? It helps you course-correct if necessary. "Most ovens are off their set point by as much as 50 degrees (mine was burning hot by 23 degrees when I tested it recently)," says Robinson. "Once you know the offset, you can simply manually adjust your set temperature to account for the offset—so, I set my oven to 325 degrees when I want to bake something at 350 degrees. Though, some fancier ovens do come with a calibration feature where you can correct the offset internally."
Less Accurate: Digital Thermometer
Any digital thermometer that records a minimum and a maximum reading will also allow you to determine the average temperature—but you'll need to do the calculations yourself. Leave the oven on for several cycles; then, average the recorded high and low temperatures and compare that to your set temperature to see your offset.
Least Accurate: Dial Thermometer
Old-fashioned dial thermometers, such as the CDN oven thermometer or the CDN High Heat oven thermometer are inexpensive, but require you to peer through the oven's glass door to read the dial. And if you open the oven door? That lets the hot air out and changes the oven's performance even more. These tools can also be difficult to read, with the reading changing by as much as 5 degrees depending on how you look at it. They are also very slow and significantly less accurate than digital thermometers—and, even worse, fall out of calibration all the time, Robinson says.
If you're going to use a non-digital dial oven thermometer, you should place it in the center of the oven in clear line of sight from the oven window and do your best to watch and capture the highest and lowest temperatures of the cycle to take your average.
Is Your Oven Miscalibrated?
If your oven is taking too long to reach the set temperature (or runs too hot or too cold) assume it is miscalibrated. However, when users complain about uneven oven temperatures, Taboryski actually doesn't point to an oven thermometer as the first fix—instead, she tells them to bake a packaged cornbread mix and follow the directions precisely.
"This is a simple, but effective test to determine consistent oven temperature. If you follow the directions precisely and get bad results, then you can take a picture to provide to the manufacturer, which will help them determine the cause of the uneven cooking," Taboryski says, noting to set your timer five minutes ahead of the suggested bake time if your oven is smaller or gas (rather than electric).