Oven Thermometers

For reliable, consistent results with recipes, a good oven thermometer is critical. When we used a high-tech digital thermometer to take the temperature of five different home ovens preheated to 350 degrees, some missed the mark by as much as 50 degrees. Here’s one big reason why: An oven’s internal thermometer only gauges the temperature of the location where it’s installed, which is necessarily in an out-of-the-way spot in the back, front, or side of the oven box. But these areas can be subject to hot spots or drafts that make their temperatures differ from the center of the oven. Only a good freestanding oven thermometer can tell you what’s really going on right in the middle of the oven, where most food cooks.

For several years, we’ve relied on our winning dial-face oven thermometer from Cooper-Atkins, but we’ve also noticed new models on the market and wondered if anything better had come along. Would we find the new best oven thermometer? We scooped up nine dial-face models, all priced less than $20, to pit against it. (We avoided bulb models since we’ve found that their tinted alcohol can get stuck and give inaccurate readings.) Most of our lineup had the option to hang from the racks or sit upright. Either way, we wanted a thermometer that was easy to position and remove for a periodic reading. In addition to ease of use, we rated the legibility of the faces and, most importantly, the models’ accuracy. Finally, to assess quality control, we purchased four copies of each thermometer and ran the entire set through testing.

Temperature Trackers

An unreliable oven thermometer is worse than none at all, so we started by evaluating each brand’s accuracy at 250, 350, and 450 degrees, using the same oven for all of our tests. We clipped a lab-grade thermocouple to the center of the middle oven rack and arranged all four copies of a model closely around the probe. We then compared their readings to the thermocouple’s.

All dial-face thermometers work by the same internal mechanism. A bimetallic strip (that is, two pieces of different metals pressed together) is wound into a tight coil and connected to a tiny dial. The two metals expand and contract at different rates when heated or cooled, moving the dial on the face. As simple a mechanism as this is, quality controls clearly vary from factory to factory. With three products, one out of the four copies faltered, registering temperatures 10 to 25 degrees off the real oven temperature.

Easy Reading

Most of the models in our lineup had thin, flat bases designed to sit atop the oven racks. Models with bases less than 2¼ inches wide were difficult to position and prone to tipping ove... read more