An instant read thermometer is probably the most important tool in a cook's arsenal. It provides the most accurate and direct indication of food's readiness. Forget old chef's tales of visual inspection or prodding with a finger; there are too many variables in the visual and tactile qualities of a piece of meat to rely on sight or touch as the indicator of doneness. If you want to know the precise state of readiness, the best option is to impale your food with a fast and accurate temperature probe. So, what should you look for when buying one?
The speed at which a thermometer can display a stable temperature is paramount. When assessing the doneness of a piece of food, the cook will slowly insert the tip of the instrument into the meat and observe the temperature changes. As the probe penetrates, the temp will drop as the tip approaches the center of the meat, and will then rise as it nears the opposite side. The lowest temp shown is the figure of merit here - it represents the least cooked part of the food. If there is significant lag between the actual temperature and the displayed temperature, the reading won't be useful. Sure, you could take several minutes slowly inserting the probe, but who has time for that? You want a quick and accurate reading of the temperature at the probe tip right now. The best instant read thermometers will stabilize in a second or two, yielding a near-instantaneous value that precisely indicates doneness.
Temperature accuracy is important, of course; however all but the cheapest thermometers are within a degree or two, so this is one of the variables that shouldn't be an issue. Because thermometers are used in a challenging environment - think dampness here - a quality unit will be sealed against moisture. Cheap units will have battery compartments that will flood if the thermometer is inadvertently dropped into the sink. Cases with mating surfaces that can admit water contain electronics that will likely succumb to spray and steam, shortening their useful lives. Cases that might leak are also more likely to break if dropped, so look for quality construction that is water resistant.
Ergonomics can also be a factor, especially if you're left-handed. Folding thermometers, pioneered by the ThermoWorks Thermapen are popular for their long probes that can be safely stowed when put in the pocket. Quality units have a display that rotates so that the numbers are properly oriented whatever the position of the case. This saves mental gymnastics when trying to decide whether that 2 is a 5 or a 2 or vice-versa. Most units will have a backlight so you can read them in poor lighting. Some require pressing a button; others auto-sense the ambient light and illuminate automatically, a handy feature. The better thermometers also have long battery life. There can be few more frustrating situations than having the button battery croak just as you're assessing the Thanksgiving turkey's readiness for the table.
We weigh these factors when assigning our product ratings: Platinum, Gold, Silver, Bronze and Not Recommended. There are many quality products out there, as well as some junk, so peruse our database and find the product that best meets your needs. Then buy with confidence.