In testing the turkey recipes for our special Thanksgiving feature (November 2009, Issue 124), we roasted 15 birds. All came with a little plastic thermometer inserted into the breast that's designed to pop up when the turkey is done. I'd always removed the device and inserted my own thermometer in the thigh instead, as the legs take longer to cook than the breast. This time I left the plastic thermometers in. Not one of them actually popped up. What gives? It turns out that Volk Enterprises, the manufacturer that makes the most widely available version of the gadget, calibrates the thermometer to activate when the turkey breast reaches 180 degrees, at which temperature the solid material in the thermometer's base liquefies and releases the spring-loaded indicator. I called Volk CEO Ed Gustafson to ask why 180 degrees was chosen as the target temperature when even the cautious USDA deems a turkey to be done at 165 degrees. "The pop up removes a lot of the guesswork," he told me. "The consumer can be assured that the bird has cooked completely." So, think of the gadget as a sort of emergency parachute for distracted cooks. You might end up with slightly dry meat if you rely on it, but you'll avert disaster.