In the spirit of the culinary celebrations that typically accompany traditional Thanksgiving festivities, we felt a justified desire to illustrate how even the simple determination of when your turkey was “done” before serving your guests very likely involved making a decision between use of a thermistor or a thermocouple! Chances are, you may not have even realized you were using “cold chain” tools on your Holiday!
Believe it or not, many of those digital thermometers we use to “check on the turkey” are consumer-friendly versions of thermistors and thermocouples. If you used a cooking thermometer with a digital display, you used a thermistor or a thermocouple for making sure that bird was ready for safe consumption.
You may be asking, “how would I know the difference between the two”? More importantly, why might you want to use one over the other? If you utilized a thermometer whose gauge and digital display is affixed directly atop of the probe device, it is likely you were using a thermistor. Thermistors are easy to use (but, you already knew that!) and reliably measure temperature through use of a ceramic tip affixed to the end of the probe. Accurate readings can take up to 10 seconds so, hopefully, you gave your thermistor time to respond.
Similarly, thermocouple type cooking thermometers also have a digital display. However, your thermocouple digital thermometer most likely had a cord attached between the probe and the display for transmitting a digital signal. Thermocouples are also reliably accurate, but do sacrifice the same level of accuracy you get from a thermistor in exchange for a faster reading (less than 5 seconds, in most cases).
So, while the choice is yours: thermistor or thermocouple, the fact remains that temperature measurement plays a factor in food safety on Thanksgiving! We hope yours was a happy one, as we look forward to the upcoming week when we look more closely at thermocouples and thermistors and their life sciences applications.