I still think of this as Jon Singer’s Turkey Algorithm, because that’s the title under which I knew it for decades; but Singer says it was devised by the late Mike Fellinger, and must be credited to him. It goes:
“For a turkey of greater than ten pounds, the roasting time should be equal to 1.65 times the natural log of the weight of the bird in pounds, cooked at 325 F.”
If you’re not a person who normally calculates natural logs, go to Google. Say you have a 20-pound turkey. Type in natural log 20 and hit the search button. Google will tell you that the natural log of 20 is 2.99573227. Multiply this by 1.65. The result will be 4.9429582455, or five hours.
And because there is no geekery without pilpul:
Ken Houghton’s Condensed Version: Just FYI, you can put the whole thing into Google. Typing in ln 20 * 1.65 (for a 20-pound turkey) yielded ln(20) * 1.65 = 4.94295825.
Erik V. Olson’s Cavil: I have to dissent from Mr. Singer’s algorithm, because we can do this vastly better emprically. The correct way to cook a turkey involves a probe thermometer inserted into the thickest part of the breast. Cook until 161F, remove, cover, let rest for 15 minutes, uncover, carve. ... Technology. It’s a lovely thing.
Henry Troup’s Expanded Principle: My best-cut algorithm is a 3/2 power law (which is a direct inversion of the square-cube principle). By my cooking log, Jon’s algorithm gives a bit longer time than I use. However, I cook at 350F, so the coefficient shifts.... I log every (big) bird I cook to refine the technique. The numbers in cookbook are a bit on the fuzzy side for my tastes. The same general algorithm can be used for things like pig roasts, too, just shift the curve to match the species and done-ness needed.
Brooks Moses’ Special Circumstance: If you have a small free-range turkey, your ideal cooking time may be considerably shorter than that yielded by the algorithm. Use a thermometer.
The Original Entry and Comment Thread: Making Light, 22 November 2007.