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NOVA ScienceNOW

Science of Thanksgiving Turkey

  • Posted 10.31.12
  • NOVA scienceNOW

Every Thanksgiving, all across the United States, humble ingredients—raw turkey, stale bread, tear-inducing onions—are transformed into mouth-watering family feasts. With help from food scientists and the staff of America’s Test Kitchen, we reveal the physics, chemistry, and biology that go into making the perfect Thanksgiving bird.

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Launch Video Running Time: 13:11

Transcript

Can I Eat That?

PBS Airdate: October 31, 2012

Thanksgiving, America's favorite holiday meal: a golden brown turkey and rich stuffing. Delicious! But a few hours ago, it wasn't such a pretty picture.

Look at this stuff. This is what we make Thanksgiving out of. They're like roots that make you cry, vegetables that are completely flavorless, this stuff. You could set a homerun record with this thing. And we eat dead animals.

Where did this idea come from? Mmmmmmm, what could be more appetizing?

And yet, somehow, through chemistry, through science, this stuff is going to coalesce into this fabulous meal. How the heck does that happen?

To find out, m going to a very special laboratory: America's Test Kitchen.

COOK: Welcome to the Test Kitchen. You need to put this on.

DAVID POGUE: This is where the PBS show and the magazine Cooks Illustrated are made. Check out how they test the tenderness of a hamburger!

COOK: Now, this is really scientific.

DAVID POGUE: So, it looks like a 4.5 on the splatter scale.

COOK: That's a really tender burger.

DAVID POGUE: The bigger the splat, the better the burger!

Unlike most kitchens, they employ an organic chemist to help figure out what is going on.

GUY CROSBY (America's Test Kitchen): When you have the skin on and the bone in you get more variation?

COOK: We get a lot of variation.

DAVID POGUE: Guy Crosby teaches nutrition at the Harvard School of Public Health. Here, he uses his science to make recipes better.

Today, the goal is a perfect turkey, filled with succulent juices. But frequently that isn't the case. The dreaded dry turkey is a pop culture cliché, and something we're all probably a little too familiar with.

I mean, this was just a waste of, this was a waste of a Thanksgiving, right there.

So why is that? A raw turkey is made up of about 75 percent water. It's also not very appetizing, and it's potentially lethal to eat, because of the bacteria growing in it. So, of course, you've got to cook it. The problem is that takes hours, and all of that heat can evaporate the water right out.

So, is there a way to get more moisture into the turkey, before cooking it, and keep it there?

I like to use the seasoning injector. It's like a prop from Pulp Fiction. I can save him! Straight into the heart. Is that a good technique?

KEITH: I'd recommend brining in a bucket.

DAVID POGUE: The cooks at America's Test Kitchen have discovered one way. They recommend soaking the whole bird in saltwater overnight, a process called "brining," which adds moisture to the meat. More moisture will make the meat more tender and juicy.

Let's back up and see what is really going on, deep inside the turkey. Meat is mostly muscle, made up of millions of fibers that are like electrical cables bundled together. Each fiber is a long cell, made up of protein and mostly water. When you heat the meat, the fibers contract and squeeze out that moisture. The more you cook it, the drier the meat becomes.

I thought we were just sticking a bird in some saltwater.

GUY CROSBY: Well, we are, but a lot of chemistry is going on in there.

DAVID POGUE: If you put a turkey into water, the H2O moves into the meat through a process called osmosis. Osmosis creates a natural force that pulls the water across the cell membrane, from the higher concentration of water to the lower one, so they're in balance. Now, meat would also absorb plain water, but the salt is key for a juicier turkey.

GUY CROSBY: The salt will help the muscle fibers to expand, create gaps, and that makes room for more water to get in.

DAVID POGUE: A few hours later, I get the tough job of analyzing which turkey is juicer, the brined or the unbrined.

Ladies and gentlemen, Sample A. Okay. That needs some serious gravy. And here we go with the second sample. Wow, that does not even need gravy.

KEITH: So, you can see the brining at work.

DAVID POGUE: The brined turkey is moist and juicy, while the unbrined…

KEITH: This…I would not finish that piece. I mean, it's really dry.

DAVID POGUE: It's super dry.

KEITH: You'd need a half cup of gravy to choke that down.

DAVID POGUE: Not all chefs and scientists agree that a brined turkey is tastier. For some, it's even too salty.

GUY CROSBY: So, we're going to see how tender they are using this instrument called a texture analyzer.

DAVID POGUE: Guy, always the scientist, puts the turkey to the test.

You're going to put your turkey into a, into a tender-testing machine?

GUY CROSBY: Absolutely.

DAVID POGUE: You must be a gas at Thanksgiving.

At Framingham State University, Guy can measure the force it takes to penetrate the meat.

GUY CROSBY: It's really like chewing in slow motion. So we are directly measuring if it takes more force to chew one versus the other.

DAVID POGUE: Side by side, we have a winner!

Whoa!

GUY CROSBY: So, it is about a 20 percent difference.

DAVID POGUE: The unbrined breast takes 20 percent more force. The tenderness machine agrees with me!

The Pogue-O-Matic 3,000.

Okay, so we solved one problem, making the meat juicy and tender, but what about flavor?

The perfect turkey is juicy inside, and outside it's got to be crispy golden brown. That color ain't just for looks. It turns out browning the outside of meat is crucial for creating the most delicious flavor, thanks to a complex chain reaction.

Now, if I'm not mistaken, Mr. Food Chemist, there's some food chemistry going on here.

GUY CROSBY: You're absolutely right.

DAVID POGUE: The key to browning and producing the best flavor is heat, lots of it.

The cooks show the difference on chicken cutlets, which are a lot easier to brown in a fry pan than a 20-pound turkey.

Heat is a form of energy that is transferred into the food. That energy can speed up the molecules inside the food, causing many possible changes.

One of them that happens quickly, once the surface of the meat gets above 300 degrees, is called the "Maillard reaction."

GUY CROSBY: Maillard reaction was discovered by a French chemist, in the early 1900s, named Louis Camille Maillard, and it….

DAVID POGUE: Mon dieu! I have discovered browning! Henceforth it should be named after moi, Mallaird.

I'm sorry I was just thinking of something.

The Maillard reaction happens on the molecular level. As we've already learned, meat is mostly muscle, which is made up of protein. Proteins are made up of molecules called amino acids. The heat from your stove breaks down the bonds in protein chains, releasing the amino acids.

GUY CROSBY: So, it's the actual chemistry that's being driven by the heat, so if you have something that's not going to heat up, you don't see these reactions taking place.

DAVID POGUE: Next, those amino acids react with sugar that's also in the meat. That sugar was there to provide the turkey's muscle with energy.

Now, on the sizzling skin, sugar and amino acids combine to create new molecules that give the turkey that delicious roasted flavor we love and the brown color.

GUY CROSBY: You take something simple, a few molecules, sugars and amino acids, and together, when they react, they can lead to the thousand different new flavor molecules created by the Maillard reaction.

DAVID POGUE: And Maillard's delectable browning chemistry isn't just for meat. You can thank the same reaction for the irresistible flavor of many things we roast, including coffee beans and chocolate.

This is something you'd see in an automotive factory.

BRIDGET LANCASTER (America's Test Kitchen): Watch this! It's like Transformers. Gone.

DAVID POGUE: You just don't want to turn it on when it's like that.

BRIDGET LANCASTER: No.

DAVID POGUE: It's a little drinking fountain.

BRIDGET LANCASTER: Clean up on Aisle 4.

DAVID POGUE: My thirst quenched, we've got to finish off the turkey, and that means it's time for that delicious combination of stale bread, tasteless celery and tear-worthy onion: the stuffing!

First, you have to battle the onion.

BRIDGET LANCASTER: You know, the way you prepare onions has a huge impact on the end result. I want you to smell this onion.

DAVID POGUE: Um?

BRIDGET LANCASTER: You can't really smell anything, right?

DAVID POGUE: It doesn't have any smell.

BRIDGET LANCASTER: No.

DAVID POGUE: Have you done something to this onion?

BRIDGET LANCASTER: No, no, that's just a regular onion, but I'm going to show you something. So, if I just take this onion and cut it right in half, by taking the blade and slicing, I've started a chemical reaction. And now you can start to smell an aroma.

DAVID POGUE: Yes, I do.

BRIDGET LANCASTER: Yeah.

DAVID POGUE: It smells like onions.

BRIDGET LANCASTER: Onion.

DAVID POGUE: The more you cut an onion, the more of that chemical reaction happens and the stronger the taste.

Inside the cell of an onion there are enzymes. These are normally kept separate from the other molecules by a barrier. When your knife cuts the onion, these chemicals come together to form new molecules. Some make you cry; others create the strong onion flavor.

So you're actually changing the flavor of a vegetable according to the mechanical action of cutting it?

BRIDGET LANCASTER: That's right. The more you go at it and more you release those cell walls, the more flavor and the more pungent aroma is going to come out.

DAVID POGUE: One of the new molecules is propanethial-S-oxide, a volatile molecule that floats up and can trigger the tears.

Assuming you survive onion cutting, it's time to move on to the rest of the stuffing.

Bridget, you appear to be the maker of the croutons. So this is how you make real stuffing?

BRIDGET LANCASTER: That's how you make real stuffing.

DAVID POGUE: I thought it comes in a box, you know?

BRIDGET LANCASTER: Only if you're desperate. The key to great stuffing is getting the moisture out of bread.

DAVID POGUE: Unlike the bird itself, where the big challenge was keeping the water in, stuffing presents the opposite dilemma: getting the water out.

If you fail, you get this: mushy, gummy stuffing.

I hate gummy stuffing.

BRIDGET LANCASTER: That was one of the Pilgrims' top 10 most hated things.

DAVID POGUE: Most recipes call for using stale bread, but, at Cooks, they have discovered a problem with that. In stale bread, the water actually gets trapped inside the crystal structure of the starch granule. So while the bread may feel dry, it actually has lost very little of its water.

BRIDGET LANCASTER: So, if you were to reheat this, you know wrap it in foil, you could actually bring back this baguette and it would be really nice and moist and you could eat it. But for a stuffing it is still going to be too moist. That's going to make the stuffing gummy.

DAVID POGUE: So how do you avoid the gummy curse?

BRIDGET LANCASTER: So you want to cut the bread into cubes, and then we dry these on a really low oven, about 250 degrees, and that's perfect because it's going to basically dehydrate the bread.

DAVID POGUE: So now, inside the starch granule there is much less water.

BRIDGET LANCASTER: So, you can see it's still moist, but the cubes are not turning to paste.

DAVID POGUE: Thanksgiving saved.

So that's our science lesson in the chemistry that will be happening in your kitchen, when you cook your turkey.

Mmmm, that is delicious, Bridget.

From making a tender and golden brown, delicious turkey to yummy, not gummy, stuffing.

Sometimes, cooking is essential for survival…
Take the cassava root…
It contains a chemical called linamarin
Inside your body, it becomes…
Cyanide!
But cook it properly…
And you get…
Tapioca.
That's right.
Cooking can turn poison into pudding!

Credits

Can I Eat That?

HOST
David Pogue
WRITTEN, PRODUCED AND DIRECTED BY
Doug Hamilton

Nathan Myhrvold Profile

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Jesse Sweet
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Joshua Seftel & Jesse Sweet
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CAN I EAT THAT? EDITED BY
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NOVA scienceNOW is a trademark of the WGBH Educational Foundation

NOVA scienceNOW is produced for WGBH/Boston

This material is based upon work supported by the National Science Foundation under Grant No. 0917517. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

© 2012 WGBH Educational Foundation

All rights reserved

Image

(turkey in oven)
© WGBH Educational Foundation

Participants

Guy Crosby
America's Test Kitchen
Bridget Lancaster
America's Test Kitchen

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