Everything You Need to Know to Cook a 20-Pound Thanksgiving Turkey

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Picture this: It's Thanksgiving morning. You've laid out your Thanksgiving table settings and set out the Thanksgiving decorations. This year, you're doing Thanksgiving potluck-style, so all you need to worry about is making the bird.

So: When does the turkey need to go into the oven? And at what temperature? How long does it to take to cook a 20 lb turkey? Should you have started cooking it early in the morning? And— oh shoot — does it need to be defrosted first?

You won't win too many awards if the turkey turns out to be inedible. Luckily, we're here to help ensure your bird is cooked perfectly — not dry as Uncle Bob's boots. Follow these helpful tips and your turkey will be the star of the Thanksgiving table.

What You Need for a Perfectly Cooked Turkey

• 1 20-lb turkey (for smaller birds, see cook times below)

• Aromatics: 1 quartered white or yellow onion, 3 carrots, 3 celery stalks, fresh herbs (such as sage, and thyme)

• A large, heavy-duty roasting pan with a rack

• Unsalted butter

• Kosher salt and freshly ground black pepper

• Baker's twine

• Aluminum foil

• An instant-read thermometer

Related: 23 Best Turkey Recipes for a Fuss-Free Thanksgiving

Fully Defrosting the Turkey

Ideally, you want start defrosting upwards of a week in advance. A frozen turkey will take approximately one (1) day for every 4 pounds to defrost in the fridge. This is the best way for full, even defrosting, though there are faster methods.

So to properly defrost a 20-pound turkey, plan for between 5 and 6 days for the bird to be fully thawed. To thaw, simply set the turkey on a large rimmed baking sheet and slide it in the fridge (cover with plastic wrap if it's not already wrapped). It really is as simple as that!

Preheat the Oven

Low and slow is the best way to cook a turkey so when you're ready to start, preheat the oven to 325ºF. Remove the turkey from the refrigerator. Unwrap it (if applicable) and remove the neck and giblets. (Save the neck for roasting and the giblets for gravy.) Let the turkey sit at room temperature for an hour while the oven heats up. (This is a good time to season the turkey. We've got suggestions below.)

What's the Best Temperature for Cooking a Turkey?

You can find recipes that suggest cooking a turkey at temperatures ranging from 325°F to 375°F or even higher. While higher temperatures will cook the bird faster, we find that they also increase the risk of an overcooked, dry, or even a burnt turkey. That's why we recommend 325°F.

Don't Wash That Bird!

Recipes at late as the 1980s and 1990s often included instructions for washing your turkey ahead of time to remove salmonella. However, research found this isn't necessary. Not only will the cooking process completely kill any bacteria, but washing just splashes raw-turkey juices and bacteria all over your sink and counter. Yuck!

Season That Bird!

When cooking anything, always start seasoning at the beginning of the cooking process so that you can build the flavors as you go. The same goes here. Place the neck and half of the aromatics in the roasting pan; top with the roasting rack. Place the turkey on the rack, breast side up, and fold the wings under; this makes for a nicer presentation.

Loosen the skin over the breast meat and rub the butter between the skin and meat. Season the large cavity with plenty of salt and pepper; stuff with the remaining aromatics. Tie the legs together with baker's twine. Season the outside of the turkey liberally and evenly with salt and pepper. Pour 1/2 cup water in the pan to prevent the vegetables from scorching.

Do I Need to Brine or Baste My Turkey?

Grandma might have done either (or both) but in fact most of the time brining isn't necessary and basting isn't helpful. If you've bought a heritage turkey or are cooking a wild turkey, which can be smaller and dryer, you may want to brine it.

Most store-bought turkeys are more than moist enough when you get them, so brining does little. (You can dry brine the bird to help impart the seasoning throughout the meat but it isn't 100% necessary.)

As for basting, buttering the turkey ahead of time will help keep the meat moist and will do much more to achieve a golden-brown crispy exterior - bonus, you won't have to constantly be opening the oven, which reduces the heat and lengthens the cooking time.

How to Cook the Turkey

Make sure the oven rack is in the lowest position—this will help the bottom of the turkey cook while protecting the more delicate breast meat on top. Slide the roasting pan into the oven, close the door, and wait!

After about 2-3 hours, take a peek. If the skin is starting to get too brown, gently lay a piece of buttered foil over the turkey. If not, keep roasting.

The surest way to tell when the turkey is done is to test the internal temperature with an instant read thermometer. It's done when the thermometer reads 165ºF. A 20 pound turkey will take between 4 to 4 1/2 hours to come to temperature if your oven is 325°F. Here are some other cook times if your bird weighs differently:

• 10-12 pounds: cook 2 3/4 to 3 hours at 325°F

• 15-16 pounds: cook 3 1/2 to 4 hours at 325°F

You'll want to start testing it at about 1/2 to 1 hour before it's supposed to be done to be sure that it doesn't get overcooked.

To do this, remove the roasting pan from the oven (close the oven door, you don't want to lose all the heat!) and slide the thermometer into the thickest part of the thigh (the easiest way to find this is to insert the thermometer into the crease between the leg and the breast), making sure you don’t touch any bones.

If the thermometer reads 165ºF, it's done. If not, slide it back into the oven.

Check it again every 15 minutes until it reaches 165ºF. Because the bird will continue to cook after it's removed from the oven, it's better to remove the bird when it's few degrees under rather than over.

Let That Turkey Rest!

When the turkey is cooked, transfer it to a large cutting board and lay a large piece of aluminum foil over the top. Let it rest between 45 minutes to 1 hour while you make the gravy. After that, carve and enjoy!

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