Do pop-up thermometers work? I don’t trust them

The Brits, known for there aversion of food thermometers – make mine steaming hot – have decide to promote a new Pop Up® disposable cooking thermometer timer device for use with all the turkeys being sold over the counter this year.

chicken.cook.thermometerThe timers are designed  to release a red button exactly when the bird has reached its optimum level of doneness at the thickest part of the meat, thus eliminating the annual ‘turkey guesswork’ and assuring a perfectly cooked and safe product.

I use a tip—sensitive digital thermometer because nothing can be more idiot-proof.

There was some group in Guelph (that’s in Ontario, Canada) that provided such advice 11 years ago,

But university beurotypes are forced to go after the easy dollar and cleaned me out for about $750K.

Whatever, I got to meet and marry Amy.

And then Kansas State University cleaned me out for $200K because, as a full professor, I got fired for bad attendance.

But back to the basics: do pop-up thermometers work?

Friend of the, Don Schaffner, provided a relevant reference:

Temperature histories at critical points and recommended cooking time for whole turkeys baked in a conventional oven

H.C. Chang, J.A. Carpenter, and R.T. Toledo

Time-temperature histories and cooking times were determined for turkeys bake at162.8°Cf rom4.44°Ct to an endpoint of82.2°C in the thigh joint or breast.Tur- keys(128)  infiveweightclassesfrom5.9to10.8kg(0.9kgincrements)were equallydividedintofresh,frozen,stuffed,unstuffed,and cooked shielded orunsheilded groups. The slowest heating point was either the wing joint or stuff- inggeometriccenter.Cooking time for unsheilded turkeys was 155min plus11 min/kg,unstuffed,and200minplus8.8min/kg,stuffed.

amy.thermometerMedian cooking loss was 23%.Shielding of breasts prolonged cooking time.The cooking end point of f82.2°C in the thigh joint provided adequate lethality against Salmonella in the slowest heating points of both stuffed and unstuffedbirds.


JOURNAL OF FOOD SCIENCE—Volume 63, No. 2, 1998

Is that a pop-up timer in your belly or are you just happy to see me; the ups and downs of turkey temps

Michéle Samarya-Timm, a registered environmental health specialist with the Somerset County Department of Health in New Jersey (represent) writes:

I roasted my first turkey as a teenager, long before I was smitten with public health as a career, and ages before I really learned to cook. I thought it was easy, especially since the pop-up timer told me dinner was ready. That bird – raw on the inside and burnt on the outside—looked okay to us. That meal was scarfed down by a group of very hungry – and very poor – college students. We knew nothing of food safety, and probably didn’t care.

It was my first encounter with a pop-up timer. Perfect for the inexperienced cook, right? When the plunger pops the turkey is done, and safe to eat. Or is it? Was that experience unique?

Since a pop-up timer is embedded in 30 million of the 46 million turkeys Americans will be eating this holiday, I sought to be a little more informed. Here’s what I found:

The pop-up timer found in turkey normally has four parts:

• The outer case (typically white or light blue)
• The little stick that pops up (typically red)
• A spring
• A blob of soft metal at the tip

The soft metal at the tip is solid at room temperature and turns to a liquid (melts) at about 185 degrees Fahrenheit . When the metal turns to a liquid, it frees the end of the red stick that had been trapped in the metal. The spring pops the red stick up and presumably the turkey is done.

Pop-up timers are thought to be relatively fool-proof because they are binary – a popped plunger means “Yes the turkey is done” and an unpopped plunger means “Nope, keep cooking.” But as with anything, this is only true under optimal conditions. Since my first turkey experience, I’ve had pop-up thermometers pop up too soon or not at all, fall apart and even disappear.

While researching this, a colleague told me Butterball turkeys do not have pop-up timers this year. Turns out, they never did. A pleasant representative at the Butterball Turkey Talk line explained. The placement of a pop-up timer is usually mechanical. This mechanical placement of the pop-up is temperamental – depending on the machines and the turkey placement (they’re slippery when raw!) — so breast, leg or other body parts may be pierced. Variations in the pop-up placement can affect pop-up timing, and presumed temperature. White meat (done at 165ºF-170ºF) cooks quicker than dark meat (where 180ºF is recommended). So instead of including a maybe-not-so-accurate thermometer, Butterball recommends using a probe thermometer to assure proper cooking. The U.S. Department of Agriculture’s meat and poultry hotline, and the Ask Karen online chat had similar information. A pop-up timer is calculated to pop when the breast meat measures about 180 degrees, which is when the leg and thigh area is most likely at the 165 degree temperature. Although pop-up timers are accurate to +/- 2ºF, they recommend verifying temperature of your bird with a thermometer that gives a numeric reading.

But what about foodsafe Thanksgiving temperatures for vegan friends? Meatless turkey substitutes are gaining in popularity, but how to best prepare a Tofurkey, a mock turkey product made of tofu, shaped like a roast? Tofu, a soybean curd that is protein-rich, meets the criteria to be classified as a potentially hazardous food. But what temperature should it reach to assure food safety? USDA didn’t have an answer. Neither (not surprisingly) did Butterball. A call to the Tofurkey folks gave me an initial answer of 350ºF, which was later corrected to 165ºF to 180ºF. And pop-up timers are not included.

Back to my initial Thanksgiving cooking disaster. I really needed a numeric thermometer to assure my cooking techniques and ancient oven roasted the meat safely. My lesson learned is that plungers are for clogged sinks. Setting a binary temperature plunger in the turkey (or tofu substitute!) brings some awareness, but nothing beats proper use of an appropriate numeric thermometer, and clear, accurate cooking instructions. It would have been safer to have an overcooked entrée masked with gravy, then the food safety disaster I fed to my friends. Thankfully, they survived.

Hopefully my lesson and my writings will assure at least a few more safely cooked, thermometer checked, meals this holiday – be it tofu, turkey, or some other tempting dish.

This Thanksgiving, I’m thankful that I have happy faces around the dining table, an accurate thin-probe thermometer to verify that my turkey won’t become the stuff of outbreak legends, and that I still have a job in public health.