How to correct an oven's temperature setting
Over time, the temperature setting on your oven can drift away from the factory setting. Then you'll find that your oven consistently bakes or roasts food faster or slower than the time specified in the recipe. Fortunately, you can recalibrate your oven to get it closer to the original setting.
First, find the oven’s average temperature
To know how much to adjust the temperature, it helps to know how far off your oven’s actual average temperature is from the temperature you set. Put an oven thermometer on the middle rack and set the oven to 350 degrees F. Let the oven preheat and then wait at least 10 minutes more for the temperature to level out from the preheating temperature spike.
Then check the reading on the oven thermometer through the oven window. Because the oven temperature rises and falls several times throughout the baking cycle, take the average of two or more temperature readings. The more readings you take, the more accurate the average you calculate will be (appliance repair technicians sometimes take a reading every minute for 10 minutes).
Set the temperature offset to make up for the difference
The difference between 350 degrees F and the average temperature you measured is the offset you'll set to recalibrate the oven. For example, if the average was 330 degrees F, the offset is 20 degrees F; if the average was 380 degrees F, the offset is 30 degrees F.
You can recalibrate most ovens by about 35 degrees F in either direction. If the average temperature off by more than 35 degrees F, you might need to replace the temperature sensor or replace the thermostat.
Here are instructions for recalibrating some common types of ovens. The exact steps vary by manufacturer, so check your owner's manual for instructions for your model. You can find the manual by searching for your model number in the search box at the top of the page.
Oven with push-button controls
Press the BAKE button just until the temperature displays the current offset setting—usually 0 or 00, unless you recalibrated the oven previously. (On some ovens, it's the TIME/TEMP button instead).
Use the arrow keys to increase or decrease the offset to make up the difference between the average you found and 350 degrees F.
Press the BAKE button to finish or CANCEL to exit without saving.
Oven with knob controls
Pull off the TEMP knob. On the back of the knob is a small adjustment screw in a track labeled Cooler at one end and Hotter at the other.
Loosen the screw just enough that you can move it.
Move the screw toward Cooler if the oven overcooks or Hotter if it undercooks. Each audible click is about 10 degrees F.
Tighten the screw and replace the knob. Repeat the process for checking the actual average temperature to see if you need to adjust the screw again.
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