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Ahhh! Tomorrow is Thanksgiving, which is definitely my favorite holiday of the celebratory triumvirate known as the "Holiday Season" (Thanksgiving; Christmas/Hanukkah/Kwanza/Winter Solstice; New Year's). Unless you're Canadian, in which case I'm about six weeks late to the feast. And unless you're English, wherein you may celebrate Get Lost Pilgrims Day. For the record, this blog post is certainly on auto-post; there is no way I'm in the office today.
 My family has always celebrated Thanksgiving somewhat irregularly. Growing up, my parents would volunteer at soup kitchens, leaving us to rush to a diner at 6 p.m. My brother, who is about a decade older than I, had no kids of his own and would do Thanksgiving at his in-laws. I was left to a day of sleeping in, football, and boredom.
Years removed from this unusual celebration, for the first time I find myself in charge of cooking a 15 lb. turkey for Thanksgiving 2013. Truth be told, I'm somewhat of a barbeque enthusiast. I've converted an old, sturdy Weber grill into a smoker, and I love spending four hours heating slabs of marinated pork ribs to a temperature that is never above 180°. I'm currently researching if smoking a whole 15 lb. turkey is feasible (seemingly no), but before I even get there I need to make sure I have my chemistry right. After all, cooking is essentially a series of chemical reactions.
Anatomy
Turkeys, as you would buy them from a store, are up to 60% water. The rest of the bird is meat, made of muscle fibers, connective tissues, and fats. Since turkeys rarely fly, the legs of the birds are fattier than the breasts. This difference in texture means that breasts do not need to be cooked as long as legs. When thawing a turkey, consider keeping an ice pack on the breasts of the fowl. This way the legs get a bit of a head start when thrown in the oven. Another option would be to construct a heat shield out of aluminum foil.
Chemistry
The flavor of the bird is mostly determined by aroma, but also somewhat by taste. Heating a bird results in a series of reactions between carbonyl groups of reducing sugars and nucleophile amino groups of the amino acids myosin and actin. This reaction, known as a Malliard reaction, gives cooked turkey its characteristic brown color, and also generates turkey's 'meaty' aroma.
Once heated above 100°F, proteins begin to denature. Muscle tissues shrink and become tougher the longer they are cooked. However, connective tissues such as collagen need to be heated to a higher minimum temperature. Heating over 140°F turns the collagen tender. A careful compromise between enough heat to denature collagen without making muscles tough to chew needs to be achieved. Furthermore, water which is attached to protein molecules is lost when it is denatured. Everyone knows moist turkey is preferred.
Cooking
There have been a few attempts to establish a reliable cooking time for turkeys. Some sources recommend following formulas outlines in Carlaw and Jaeger's 1947 Conduction of Heat in Solids. However, this method is imperfect since it assumes several conditions about the bird's cooking environment and volume.
Instead some years ago Wolfgang Panofsky, a true lover of turkey meat, professor of physics, and particle accelerator director at Stanford University created his own equation for timing a turkey. He noted that many guidelines for turkey cooking present a linear equation, and he disagreed with that assumption. Through trial-and-error (read: eating a ton of turkey), Panofsky developed the following formula, with a turkey cooked at 325°F.
where: t equals time, and W equals weight of the turkey
Turkey Time
Of course, since I'm cooking the turkey, I'm not making a single side. The rest of the family will have to do that. Perhaps if I can get the turkey done early, I can enjoy a sleepy evening of gorging and football.
Happy Thanksgiving from CR4!
Resources
About - Turkey Physics
Phys.org - How to cook the perfect turkey
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Re: Cooking Chemistry: Turkey Time
