Published November 1, 2007. From Cook's Illustrated.
Maintaining the proper refrigerator and freezer temperature is essential to keep food as safe as possible—our favorite model simultaneously monitors the temperature in both the freezer and refrigerator.
Heavy cooking around the holidays means constantly opening your refrigerator and freezer, which causes temperatures to fluctuate. To monitor the safety of our cold storage, we use refrigerator and freezer thermometers. But is one model really superior to another? We chilled six brands (plus a digital thermocouple, which recorded our control temperature) to find out. All six offered wide temperature ranges (the lowest from -40 degrees to the highest at 86 degrees) and gave accurate readings, proof that shelling out a lot of money is unnecessary for simply reading the temperature. Spending a little more, however, will buy you space-saving convenience and a few bells and whistles. Analog models mounted on door shelves, but one brand was a struggle to clip on. Another model lost points because it had to sit on or hang from a shelf, taking up precious space, and was easily knocked over. The best analog model suctioned securely to the wall and sported an adjustable, easy-to-read display.
A step up were digital, wall-mounting models. In addition to exact readings and ultra-clear displays, both also offered alerts—the former beeps, the latter lights up automatically—when temperatures rise into danger zones (above 40 degrees for the refrigerator; above 0 degrees for the freezer). But one standout, which puts a probe on a 75-inch wire that can easily reach a top, bottom, or side-by-side freezer, has earned a permanent spot in our cold storage for displaying simultaneous fridge and freezer readings. It’s our new favorite.