Monday, November 22, 2010
Talking Turkey -- Using Science to Cook the Perfect Bird
But how many of us actually get it? How many of us have worked out that seemingly magical combination of basting and cooking times so that we reach this Holy Grail of Turkeydom? Surprisingly, not so many!
Let us help you get a little closer to that dream this year by breaking down some of the science behind roasting the perfect bird.
The first thing to understand is the physiology of our illustrious Meleagris gallopavo. Turkeys are birds, which means that they fly. Right? But, they also spend a lot of time walking about on the ground. As a result, the muscle mass in a turkey's body is pretty much split up into two groups: the breast and the legs.
The breast muscles are located close to the bird's center of gravity, which helps it both flap its wings and control its position in flight. But turkeys don't migrate -- they hang around their home turf all year round. In reality, the heavier percentage of a turkey's lifetime activities are spent on their two little legs, not flying about. Flight is typically reserved for roosting in trees and quick escape from predators. This means that the more heavily used leg muscles are both greater in concentration of fat (because fat is an energy store) and full of blood-enriched tissue (because oxygen is required for energy conversion).
It's this discrepancy in muscle use that accounts for the difference in meat color and texture. The lesser used breast muscles are white and leaner, while the more active leg muscles are a nice dark color with more fat. Wild turkeys and those that are free range will tend to have a higher percentage of dark meat than those birds raised in mass production farms -- mainly because they get more exercise. (This in true for chickens, too, incidentally.)
So what does it matter that the turkey uses its legs more than its wings? It means everything. Muscles are a combination of water, fat, and protein.The fibers within the muscle are primarily protein, and these need to be broken down in order for our bodies to process their goodness. Adding heat to our bird is what breaks down these muscle fibers.
The meat fibers as a whole tend to break down around 180 degrees Fahrenheit, unraveling and making our bird more tender. But if we apply heat for too long, those proteins begin to coagulate and make the bird dry and tough. The trick, here, is that the breast meat and the leg meat have different proportions of water, fat, and protein AND the amount of mass of the sections are different. (The legs are sticking off the body and smaller in size than the breast, right? They aren't going to cook at the same rate.)
What happens if we put our bird in the oven and cook it until the breast meat is a gorgeous 180 degrees Fahrenheit near the bone? The legs are overdone and falling off the bird. And if we cook it until the legs are a perfect 180 degrees? The breast meat is undercooked and tough.
So, how do we get moist, tender breast meat AND moist, tender dark meat?
Tricks for evening cooking time
We want our bird to come out of the oven with everything in a perfect state. In order to accomplish this, we need to accommodate for the cooking differentials explained above. Some will tell you that this means slowing down the cooking of the breast, and speeding up the cooking of the legs because dark meat takes longer -- but that ignores the fact that the legs are smaller in overall size than the breast. Though pound for pound leg meat will take longer to cook than breast, overall there is less leg meat on your Thanksgiving bird.
So what do we do?
Chef Iain Falconer of Olive's in NYC does NOT recommend putting ice packs on your turkey's breast for the hours leading up to the roasting, as you might read elsewhere. By cooling the meat down considerably, and letting the legs stay at room temperature, the time it takes for the breast meat to warm to cooking temperature will give the legs too much of a head start. Cooling the legs is a better idea, though not very practical. Instead, cover the turkey's legs with aluminum foil. The foil reflects the oven's heat significantly enough to create a temperature difference between the two parts of the bird. Take the foil off somewhere at the start of the last hour to get a beautiful color on the skin.
How long in the oven?
Once you've established that temperature difference in the muscle tissue, it's time to put your bird in the oven. Add some water or broth to the pan to stimulate steaming (and thus juiciness), then pop it in at 475 degrees Fahrenheit for 15 minutes. Starting high will cause the heat to hit your bird's skin first, which will force the fat to melt and the protein to unravel, then coagulate to form a nice crispy outer cover.
After 15 minutes, reduce the cooking temperature to 375 degrees and cook according to the weight of your bird. A turkey's perfect cooking time is 15 to 20 minutes per pound of weight, plus an extra 15 to 20 minutes at the end. If your bird is small, aim toward 20 minutes per pound; larger birds, aim toward 15 minutes. (This may seem illogical at first, but a smaller bird will be in the oven less time overall than the larger, so you'll need the little bit of extra time to make sure it's all cooked and the proteins are unraveled.)
When the breast meat has reached 180 degrees, all bacteria will have been killed. Your juices should run clear, and you can leave the bird to rest outside of the oven for 20 minutes to cool and reabsorb that moisture back into the meat. Cutting while fresh out of the oven will send the good juice into the gravy and not into the muscle fibers, leaving Tom the Turkey dry.
To stuff or not to stuff, that is the question
When a turkey is prepared for roasting, what is in its center? Nothing -- it's empty. Empty except for the various bacteria, like Salmonella, that tend to thrive on raw poultry products. If you then put stuffing into that cavity, you not only increase the overall mass of the bird, you create a wonderful haven for those bacteria to have their own little Thanksgiving party.
In order to raise the inner cavity (the stuffing) to the bacteria-killing temperature of 180 degrees Fahrenheit, you're going to need to roast that bird for a lot longer than the times described above. Which will result in what? You got it -- tough, dry, chewy turkey. Exactly what we're trying to avoid.
So, if you want that wonderful flavor of the bird infused into your 'stuffing', don't put it into the bird. Instead, use some of the juices from the cooking process to add flavor. If you're a bread stuffing fan, skip the water and use the juices to moisten that bread.
Have some tricks of your own you would like to share for a perfect Thanksgiving Feast? Share them with us on our Facebook page, or in the comments section below!