How Pop-Up Turkey Timers Work

A Funky Thermometer
On the left is a pop-up timer before cooking, and on the right is the same timer after it has popped up. HowStuffWorks

If your turkey has a pre-inserted pop-up timer — most turkeys you buy from the grocery store do — you don't have to worry about using a separate meat thermometer. When the turkey's timer pops up, it's signaling to you the bird is done. Here's how it works:

A pop-up timer found in a turkey or chicken normally has four parts (see image above):

  • A: The stick that pops up (typically red)
  • B: The outer case (typically white or light blue)
  • C: A spring
  • D: Piece of soft metal similar to solder

The soft metal (D in the image) is solid at room temperature but turns to a liquid (melts) at about 165 degrees Fahrenheit (73 degrees Celsius). When the metal melts, it releases the red stick (A) and the spring (C) pops up the stick so you know the turkey is done.

Turkey is done when it reaches 165 degrees Fahrenheit (73 degrees Celsius). If your turkey didn't include a pop-up timer, you can use a meat thermometer to check the internal temperature for doneness. Simply insert the thermometer into the innermost part of the turkey's thigh and wing, and the thickest part of the breast, being sure not to hit bone. If it registers 165 degrees Fahrenheit, it's done.

One little-known fact is that these timers are reusable. If you dip the tip in hot water it will re-melt the metal and you can push the pop-up piece back into place. Then let it cool, and the pop-up piece will be back in its original position — ready to use again.

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