An oven thermometer is a crucial tool for any baker because ovens aren’t always that reliable. Not only can they easily be off by 5-10 degrees – especially if they have never been recalibrated – but the simple act of opening the oven door can release enough heat to impact the time your cake will need to finish baking. An oven thermometer will give you an accurate read on the reliability of your oven and let you make any necessary adjustments, such as turning up the temperature a little bit or decreasing the baking time by a few minutes, to ensure that you get good results in your baking.
But as with all kitchen gadgets, all oven thermometers are not created equal. Some are more accurate than others and some brands are more durable. Cook’s Illustrated tested several brands of oven thermometers in their high traffic test kitchens over a period of 6 months and reported their results in their most recent issue (Jan/Feb 2011). They prefer dial-face thermometers because they tend to be more accurate and limited their test to that type of oven thermomener. Their winner was The Cooper-Atkins Oven Thermometer, which remained accurate and easy to read throughout their months of testing. This was the least expensive thermometer, too. Second place was the CDN Pro Accurate Data Hold Oven Thermometer, which was accurate but very difficult to mount inside of an oven. The other models they tested were prone to breaking, fading numbers and inaccuracy over time.
Frequently replacing an oven thermometer every few months when they start to fade or if you suspect inaccuracy is a great way to ensure that you get better performance from any thermometer, regardless of brand, as well.