The Science behind the Perfect Christmas Roast!

Christmas day is looming. That hallowed day of food, wine, gifts, food and then some more food is nearly here!

Mmm, tasty!
In the UK, ten million turkeys will be cooked, 25 million Christmas puddings eaten, and six million gallons of wine drunk! The chances are that you will be eating roast turkey at some point this next week (unless you’re vegetarian).

But how many of us know the best way to cook a roast? Have you’ve ever wondered what actually goes on in the food you cook? If you like cooking or eating, then today’s post is for you!

Warning: Reading today’s blog may make you decidedly hungry…


Step 1: Put the Turkey in the Oven

Following today’s recipe (see bottom of the post), your foil-wrapped turkey will need to go in a nice hot oven. It will be in there for quite some time, and it won’t be long before nice smells will be spreading around the house…

Behind that dark oven door, the meat is cooking – but what exactly is going on? And why does the oven have to be so hot?

Uncooked meat looks pretty different to cooked meat

While you scrub the veggies and sip on a glass of port, uncooked pink flesh is slowly turning into succulent and appetising meat. Meat is made of muscle; and muscle contains lots of protein. Protein are cleverly designed microscopic molecules designed to let living muscles contract. When you cook meat, these proteins get destroyed in a process called ‘denaturing’.

The process of cooking makes millions of protein to irreversibly changed their shape: They are 'denatured'

Proteins are too tiny to see but when they denature, the meat changes colour. The same thing is happening when you fry an egg and the egg white goes from clear to white.

Does your oven need to be really hot to cook the meat? Surprisingly, proteins denature at only 40 degrees C! I wouldn’t try to cook your turkey 40 degrees C if I were you: You’ll be waiting a very long time and you could get more than you bargained for…

If you don't cook meat at a high temperature, bacteria will grow and you could end up with a nasty bout of food poisoning

Step 2: Take the foil off

If you’ve been following the recipe below (at the bottom of this post), your turkey will be roasting away in a nice foil ‘tent’. Your little aluminium sauna has been keeping all the moisture inside, stopping the bird drying out. But if you want your turkey to have a tasty crispy skin, you are going to have to let some of that moisture out…

The shiny side of foil reflects heat, so put the shiny side inwards if you want to roast quicker!

That super-tasty brown crust only happens in the right conditions: The outside of the meat must be very hot and dry. If you get it right, something called the ‘Browning Reaction’ takes place: Proteins and sugars mix and react to produce some fantastic meaty-flavour chemicals!

The 'Browning Reaction' also happens on any grilled or fried meat. The meat needs to be very hot: over 150 degrees C!

If you’re roasting beef, pork or lamb this winter, you may like to ‘seal’ the meat first. You seal meat by frying it in a hot pan before putting it in the oven; giving the meat the same brown meaty crust. If you’re a Masterchef fan like me, you’ll probably have heard TV chefs say that sealing “traps the juices in”. It doesn’t, but is does help it taste nice! I must remember to tell Michel Roux Junior about the ‘Browning Reaction’ next time I’m having lunch in Le Gavroche…

Searing or Frying meat is another way to cause the 'Browning Reaction'

Step 3: Resting the meat

The turkey is out of the oven and it’s looking delicious! The house has filled with fantastic Christmas aromas and so isn’t it about time to slice the meat “just to check it’s ok”?! If you want the perfect roast, you’d better keep those hunger pangs at bay by chomping on another mince pie! As every chef and good cook knows, meat cooked in the oven needs to be ‘rested’ before carving.

Don't eat it just yet: The best things come to those who wait…

I owe a lot to TV cookery shows: They taught me both the skills to feed myself as a student and gave me the gastronomical prowess to woo my wife on our first date! Celebrity chefs don’t always get everything right though! It is often said that ‘resting’ meat allows the muscle fibres in the meat to ‘relax’. Sadly, very wrong…

Even though Gordon Ramsey’s muscles might be hot and tense after an afternoon in the kitchen, a cooked turkey’s muscles certainly aren’t! After three hours in the oven, all the muscle proteins have been ‘denatured’ so this turkey’s about as relaxed as it’s ever going to be…

The real reason to rest your meat is to let the moisture spread throughout the meat. When you take the bird out of the oven, the outside is hot and dry but the middle is cooler and wetter. So by sitting your cooked turkey at room temperature for at least half an hour gives it time for the fluids to spread out throughout the meat.

Not for you Fido! The turkey is resting…

And when the waiting is over, you will have a perfectly cooked, succulent roast Turkey (just don’t let the dog get to it first)!

There you have it: The science behind a perfect Christmas roast!

Read more on the science of cooking:

The ‘Browning Reaction’ is also called the Maillard Reaction, you can get the low down on it at

A good, if rather cheesy explanation of the science of food with video clips at:

Science of foil!: Learn how scientists discovered what chef’s knew all along at

Learn more about what happens to proteins when we cook them here

Find out about what gives meat its flavour at The Accidental Scientist

Some interesting Christmas facts and stats at!

Basic Roast Turkey Recipe:

You will need:

One whole turkey
1/4 cup olive oil
1/8 teaspoon salt
1/8 teaspoon freshly ground pepper

  • Preheat oven to 450°F (230°C).
  • Wash and dry turkey inside and out. Rub turkey lightly with olive oil, salt and pepper .
  • Cut a long length of aluminum foil, enough to wrap loosely around the turkey. Lay it across the bottom of your roasting pan with edges overlapping the sides of the pan. Place a rack on top of the foil and set the turkey breast-side up on the rack. Bring ends of foil up around turkey and crimp together along top of turkey. Foil should be loosely wrapped around turkey and crimped together at ends. Put turkey in oven and roast for 15 minutes. Turn heat down to 375°F (190°C) and cook until done.
  • Use following chart to gauge time:
    8 to 10 pounds (4kg): 2 1/2 hours;
    10 to 14 pounds (5-6kg): 2 1/2 to 3 hours;
    14 to 20 pounds (7-9kg): 3 1/2 to 4 hours.
  • During roasting, the bird should be basted occasionally and turned 3 times, that is, rolled onto all of its sides. Open foil to do this and turn turkey first on one side, then on another, then upside down. Finally, turn it right side up and remove foil for final browning.
  • The turkey is done when you stick a fork, knife, or skewer in and clear juice (as opposed to pink) runs out. A meat thermometer inserted into the part of the bird without touching the bone will read 180°F (approximately 80°C). Do not overcook. Remove turkey from oven and let sit 15-30 minutes before serving so that juices will be reabsorbed by the flesh.
  • Carve the turkey and transfer to a serving tray.

Recipe available from

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