How Long Does A 18 Pound Turkey Cook

Easy Thanksgiving Roasted Turkey! Here you'll learn all you need to know to cook the perfect juicy and tender turkey, the secret starts with an oven bag. It's a breeze to prepare and it turns out delicious every time following a few simple steps!

This post was sponsored by Reynolds Kitchens, however all thoughts and opinions are 100% my own.

Turkey on a serving platter with fruit and fresh herbs.

Easy Juicy Thanksgiving Turkey

Growing up whenever my mom made a turkey it was always with a Reynolds Kitchens Turkey Oven Bag. My mom still swears by them because not only is it the easiest way to cook a Thanksgiving turkey but the turkey always ends up juicy and tender. The oven bag takes out a lot of the extra work, no brining, basting and so forth.

I also love to use them because no one likes a dry turkey and it takes out a lot of the worry in ending up with a dry turkey. Plus the turkey cooks faster in an oven bag and clean up is easier!

The oven bag locks in flavor and the steam in the bag bastes the turkey as it cooks. And it's important to know Reynolds Kitchens Turkey Oven Bags are made of heat-resistant nylon that is FDA approved and they are BPA-free.

If you are new to roasting turkey it can be intimidating and I think this is one of the best methods to start with. Nothing complicated or hard to understand, just a straightforward and foolproof method that you'll want to use time and time again!

Slicing into a whole turkey.

What Do You Need for This Roasted Turkey?

Tools for a roasted turkey:

A Reynolds Kitchens Turkey Size Oven Bag – these can usually be found by the aluminum foil and plastic wrap at most grocery stores.
Large roasting pan – a disposable aluminum roasting pan will work fine here for small-medium turkeys.
Instant read thermometer – this helps ensure you cook the turkey to the proper temperature so there's no risk of food borne illness.

Ingredients to make a roasted turkey:

12 – 24 lb turkey – a larger turkey tends to brown better in a bag since it has to cook longer (I used an 18 pound turkey here) but keep in mind all ovens vary a little.
Flour – this is used to keep the oven bag from bursting.
Salt – this is the most important ingredient in seasoning the turkey.

Then I like to up the flavor a little so I also add:

Onion, carrots, and celery – these fresh vegetables season the drippings for gravy.
Pepper – because why not?
Dried or fresh thyme – other poultry herbs work great here too (parsley, rosemary, sage or marjoram).
Garlic – I love garlic but if you don't you can omit it.

Making butter garlic herb mixture in a glass mixing bowl.

How to Cook A Turkey in An Oven Bag:

Preheat oven: Move oven rack one level below center and preheat oven to 350 degrees.
Prepare turkey: Remove neck and giblets from turkey and remove any pin feathers left behind. Tuck wings under turkey. Season cavity of turkey with salt and pepper.

Make butter mixture: In a small mixing bowl stir together butter, garlic, thyme and season with a little salt and pepper.

Separating turkey skin from breast using the back end of a wooden spoon.

Rub butter under turkey skin: Using the back end of a wooden spoon separate turkey breast skin from breast. Rub butter underneath skin (again I just use the back end of the spoon), smooth over skin to spread butter out. Altnerately you can just rub butter over skin but I feel it seasons better when rubbed underneath.

Season: Season all over turkey with a fair amount of salt and pepper.
Prepare oven bag with flour: Add 1 Tbsp flour to the bag and shake, don't skip this ingredient.

Adding flour to an oven bag.

Add vegetables to oven bag: Place bag in a roasting pan, add celery, onion and carrots to oven bag.

Chopped onion, celery and carrots in a roasting bag.

Add turkey to oven bag: Place turkey over vegetable layer.

Putting turkey in an oven bag in a roasting pan.

Tie and cut slits in oven bag: Close oven bag with the tie included with oven bag. Cut 6 slits across top of the oven bag to allow steam to escape then tuck ends of oven bag into the pan.
Roast: Bake until turkey registers 165 degrees in thickest portion of breast in several places and 175 in thigh. Refer to times listed below for an estimate.

Cutting slits in an oven bag with a large turkey inside.

How Long to Cook a Turkey in An Oven Bag?

Again these times are just estimates, every oven varies and temperature of turkey going in to oven contributes as well. Always test temperature to ensure it reaches 165 degrees in thickest portion of breast and 175 in thigh in several places for doneness.

UNSTUFFED TURKEY IN OVEN BAG:

10 – 12 pounds: 1 1/2 – 2 hours

12 – 16 pounds: 2 – 2 1/4 hours

16 – 20 pounds: 2 1/4 – 2 1/2 hours

20 – 24 pounds: 2 1/2 – 3 hours

STUFFED TURKEY IN OVEN BAG:

10 – 12 pounds: 2 – 2 1/2 hours

12 – 16 pounds: 2 1/2 – 2 3/4 hours

16 – 20 pounds: 2 3/4 hours – 3 hours

20 – 24 pounds: 3 – 3 1/2 hours

Let turkey rest 20 minutes after removing from oven. Carefully cut top of oven bag open, transfer turkey to carving board and carve.

Turkey shown after cooking sitting in a roasting pan.

Tips for Oven Bag Roasted Turkey:

Be sure to add flour to oven bag and to cut slits in the oven bag so steam is able to escape so oven bag doesn't burst.
Don't let oven bag touch top element or sides of oven or it can melt. This is why it's helpful to move oven rack down a level and always tuck the oven bag ends under so they don't hang out the edges of the pan.
Always test the temperature when roasting turkey. The thickest part of thigh should be 175 degrees and breast should register 165 degrees on an instant read thermometer.
Avoid using pop up timers as they can get stuck and aren't very accurate anyway.
Add butter and seasonings for extra flavor.
Let turkey rest before carving to allow juices to redistribute.
Careful when cutting bag open as there will be hot steam inside.

Overhead image of large turkey with golden brown skin, sitting in an oven bag in a large roasting pan.

What Sides to Serve with It?

Green Bean Casserole
Mashed Potatoes
Slow Cooker Creamed Corn
Slow Cooker Stuffing
Sweet Potato Casserole

How to Cook Turkey

How to Cook Turkey {In an Oven Bag}

Servings: 12 -24

Prep 15 minutes

Cook 3 hours

Cool 20 minutes

Ready in: 3 hours 35 minutes

12 - 24 lb. turkey (fresh or frozen and fully thawed)
1/4 cup butter, softened
3 garlic cloves, minced (1 Tbsp)
1 tsp dried thyme, or 1 Tbsp chopped fresh*
Salt and freshly ground black pepper
1 Tbsp all-purpose flour
4 celery ribs, chopped into 2-inch pieces
1 large yellow onion, peeled and chopped into chunks
2 carrots, peeled and chopped into 2-inch pieces

Move oven rack one level below center and preheat oven to 350 degrees.
In a small mixing bowl stir together butter, garlic, thyme and season with a little salt and pepper.
Remove neck and giblets from turkey and remove any pin feathers left behind. Tuck wings under turkey. Season cavity of turkey with salt and pepper.
Using the back end of a wooden spoon separate turkey breast skin from breast. Rub butter underneath skin (again I just use the back end of the spoon), smooth over skin to spread butter out. Altnerately you can just rub butter over skin but I feel it seasons better when rubbed underneath.
Season all over turkey with a fair amount of salt and pepper.
Add 1 Tbsp flour to the Reynolds Kitchens Turkey Size Oven Bag and shake. Place oven bag in a roasting pan, add celery, onion and carrots to oven bag. Place turkey over vegetable layer in oven bag.
Close oven bag with the oven safe tie included. Cut 6 slits across top of the oven bag to allow steam to escape then tuck ends of oven bag into the pan.
Cook unstuffed turkey according to size (the breast should register 165 degrees in center of thickest portion in several places and the thigh 175 degrees on an instant read thermometer):

12 - 16 lb turkey: 2 - 2 1/4 hours

16 - 20 lb turkey: 2 1/4 - 2 1/2 hours

20 - 24 lb turkey: 2 1/2 - 3 hours
Let turkey rest 20 minutes. Carefully cut top of oven bag open, transfer turkey to carving board and carve.

Plan about 1 lb of turkey per person, for example a 12 lb. turkey should feed about 12 people, a 24 lb. turkey should feed about 24 people.
To thaw a frozen turkey allow about 24 hours for ever 5 pounds of turkey thawing in a refrigerator set to 40 degrees. I like to add an extra day just to be safe. A fully thawed turkey can be held in the refrigerator 2 more days.
*Other herbs work great here including parsley, rosemary, sage or marjoram. You can also add lemon zest to the butter mixture if desired.
Ensure that oven bag does not touch top element or sides of oven or it can melt.