# Heat Transfer When Roasting a Turkey

## Spherical turkeys and the Panofsky equation

Recently I decided to research heat transfer during turkey roasting. It turns out that this issue has been extensively studied by physicists and engineers.

As with houses, there are two basic camps: those who use computer modeling and those who make measurements. Some researchers feel more comfortable at a desk with a laptop; others feel more comfortable in a kitchen with a thermometer.

### This was a cursory review

I wasn’t able to review all of the relevant literature. For example, I didn’t read the 1998 paper by H.C. Chang, J.A. Carpenter, and R.T. Toledo, “Modeling Heat Transfer During Oven Roasting of Unstuffed Turkeys,” because I’m too cheap. (You have to pay a fee to Wiley Publishers to download the article.)

According to the abstract, “A finite element method was used to solve the unsteady state heat transfer equations for heating of turkeys in a conventional electric oven.”

My inability to read this paper doesn’t bother me too much, however, since I’m more interested in measured data than computer modeling.

[Author’s postscript: A GBA reader named David Fay kindly e-mailed me the paper by Chang, Carpenter, and Toledo. The researchers wrote that “Simulation results revealed that increasing oven temperature reduced baking time but resulted in breast temperature reaching the designated endpoint much earlier than what would be required for thigh joint temperature to reach the endpoint.” One of the researchers’ notable achievements was the development of the turkey brick and the turkey cylinder. They wrote, “Intact turkey muscles were made into 10.2 Ã— 7.6 Ã— 2.54 cm brick-shaped samples. The simple geometry simplified calculations of the surface heat transfer coefficient. … Turkey breasts were cored into cylindrical samples 2.54 cm dia. Ã— 15 cm. The thermal conductivity probe was inserted into the center of the sample.”]

### What shape is a turkey?

Researchers…

1. | | #1

room temperature?
Anyone with a meat thermometer will attest to the fact that it takes many hours for a refrigerated turkey to come to room temperature. Don't bother, unless part of your science project is an investigation of bacterial growth.

Spherical or cubic turkeys? Don't give the industrial food complex any more ideas. It's bad enough that the turkeys can't mate anymore.

2. GBA Editor
| | #2

Response to Stephen Sheehy
Stephen,
Good point. Two of the quoted experts mentioned bringing an uncooked turkey up to room temperature.

One was John C. Polking, who apprears to be more interested in his Dirichlet equations than the problem of bacteria.

The other was William Hammack, who probably should have known better. I think it's usually best to get the turkey into the oven before it reaches 72°F.

3. | | #3

Ha
This reminds me of a joke, where for the punchline a physicist says something along the lines of "first, let's assume that a cow is a sphere on a frictionless plane in a vacuum"

4. | | #4

Moisture is easy...
...compared to heat. 1. No stuffing in the turkey--it robs moisture from the meat. 2. Breast down, not up.

5. GBA Editor
| | #5

Response to Bill Rose
Bill,
You wrote, "No stuffing in the turkey--it robs moisture from the meat."

Is that based on moisture modeling or side-by-side taste testing of two roasted turkeys?

6. GBA Editor
| | #6

Response to Aaron Birkland (Comment #3)
Aaron,
More on spherical cows:
http://en.wikipedia.org/wiki/Spherical_cow

7. | | #7

Panofsky
Architects would surely recognize Panofsky as Erwin Panofsky, art and architecture critic. Father of Pief, grandfather of Nicholas, buddies with Einstein at Princeton, and Fermi.

8. GBA Editor
| | #8

Response to Bill Rose
An excerpt from Unnatural Wonders: Essays from the Gap Between Art and Life by Arthur Coleman Danto: “This is nowhere more evident than in [John Currin's] strange Thanksgiving of 2003. Three festively dressed women are gathered around a table like a coven of witches, with some pieces of fruit, a few roses in a glass pitcher, and an immense uncooked turkey. The turkey appears to be thawing -- it sits in a puddle of pink juice. … The painting cries out for the kind of interpretation that Erwin Panofsky once gave of Bronzino’s Venus, Cupid, Folly, and Time.”

.

9. GBA Editor
| | #9

This blog was rushed to publication to meet this morning's deadline. I have just added a concluding section to the blog, "Lessons for designers and builders."

10. | | #10

Happy Turkey day... you have
Happy Turkey day... you have us all drooling in anticipation

11. | | #11

Humility
Love the post script. Humility was on my mind all day by coincidence. Do justice, etc.

12. | | #12

Modeling is for something that can't be Measured
Just set the oven on convection roast with probe control set to shut off at an internal temperature of 185. Perfect results because measurement and past experience takes the guesswork out of it. Blower door, kw hours and degree days prove a build which becomes the 185 metric for the next construction site.

13. | | #13

Cooking a turkey with potential energy...
You may have missed one cooking method, definitely an experimental venture: from a favorite journal, http://www.ohio.edu/mechanical/thermo/Intro/Chapt.1_6/energy/CookingPE.pdf .
Presumably this works with frozen turkeys as well.

14. GBA Editor
| | #14

Response to Bill Dietze
Bill,
The "cooking with potential energy" paper was by far the best paper I've read by academic researchers looking into this question. Thanks for sharing it.

15. | | #15

Running hot and cold
Thanks for the entertaining and useful article. It's interesting that two turkey-cooking trends take traditional thermal techniques to task; taste, texture, and moisture from either cooler or hotter cooking protocols [deep-fried turkey, and slow-cooked for >10 hours] are claimed by their supporters to be superior.

16. | | #16

I wouldn't be surprised...
I wouldn't be surprised if the Japanese have created spherical turkeys that would allow us to do a better job of modeling turkey heat transfer. I mean if they can create square watermelons...

17. GBA Editor
| | #17

Response to Rob Wotzak
Rob,
Yes, the Japanese are working on it. Their breeding program is ongoing.

Shown below is a prototype -- Spherical Turkey 1.0.

.

18. | | #18

Update
They're well beyond the prototype, Martin - here it is being transported to the new test facility.

19. | | #19

Panofsky Family
Erwin the art historian was father to Pief, but I believe great-grandfather to Nicholas. (Pief was Nicholas's grandfather.)

Thanks to all for the enjoyable post and comments, and a Happy Thanksgiving as well.

20. | | #20

Oops
I just realized I may have misread the syntax of Bill Rose's Post No. 7. Apologies if this is so.

21. | | #21

Tofurkey
The tubular nature of the ever-popular Tofurkey, which is annually served to the vegan in my household, should be much easier to model. But, as even reading this Holladay/holiday post gave me a headache, I will not even attempt to do the math. Needless to say we simply follow the directions on the box and hope our lower carbon foot-print makes up for the cardboard and plastic packaging. Happy T-day to all at GBA!

22. | | #22

An engineer is walking down the street
And sees a woman on a ledge, getting ready to plunge to her death.

"Don't jump" he cries. "You have so much potential!"

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