Prime Rib Fat Side up or Down: Which Way Should You Cook It?

Are you wondering if you should place your prime rib fat side up or down?

We all know that prime rib is an expensive cut and you don’t want to mess it up.

Especially when you have the whole family waiting to see how your prime rib turns out! 

Well, don’t worry below you’ll learn how to turn out a perfectly cooked prime rib.

Just make sure you follow all the steps and you’ll nail it


Do We Smoke a Prime Rib Fat Side-Down or Up?

The best way to smoke a prime rib roast is the fatty side up!

Techniques like this in a cooking process matter.

Read on further to understand why.


The Reasons for Smoking Fat Side Up

With the fat cap facing away from the heat it is less likely to burn.

Gravity will also go to work by ensuring all the tasty rendered juices are absorbed back.

So you can be sure of maximum flavor for the holiday season.

In other types of roasts and recipes like brisket, it is common for the fat to be facing down.

Towards the direct heat on the grill grate.

This means the connective tissue and fat are properly rendered and edible.

But with a rib roast, you can shallow fry the meat fat beforehand.

The direct heat seals and starts the rendering process.

But more of how you can achieve a flavorful crust later!


Benefits of Cooking a Rib Roast Fat Side Up

– Re-absorption of juices for tender meat and a combination of flavor layering.

– Your extra rib roast ingredients and seasonings like fresh herbs are less likely to fall off.

– Easier carving and presentation.


The Different Types of Fat in a Prime Rib

Below are 4 types of fat you will find in your prime rib roast.


Subcutaneous Fat

Subcutaneous fat or the fat cap is a layer on the outside of the lean beef.

Intermuscular Fat

This is fat between and on the muscle proteins.

Intramuscular Fat

The marbling of fat between the muscle fibers.

Intercostal Fat

This fat is attached or in between bones like the ribs.

Cuts of Beef Need to Be Trimmed Properly

The fat cap on a prime rib can be up to 2 inches thick.

This is way too much, for any cooking method.

A prime rib is expensive and for special occasions.

So respecting and preparing before cooking is important.

Ask your butcher to trim down the fat cap to 1/2 an inch.

Sealing the Fat Cap Before Cooking

Crust creation on the beautiful meat of a prime rib is what makes it the king of roasts!

Sealing the fat does the following;

– Bold flavor from the umami brown crust.

– Start the rendering process for a consistent cook time and even cooking.

– Another stage for adding extra flavors like fresh thyme and garlic powder.


Cooking Tips for the Perfect Crust

– Lightly cover a cast iron pan with olive oil.

– Put on direct grill heat until smoking.

– Liberally apply kosher salt to the fat cap.

– Put the salted fat side down in the oil.

– Fry until golden.

– Seal the other side for half the time of the fattier side.

– Add butter and your choice of aromatics like rosemary, black pepper or your other favorite herbs.

– Cover with aluminum foil for no longer than 15 minutes until ready to cook.


Cooking Low & Slow for Best Results

Slow cooking at 225°F is best after sealing the fat.

A large cut of meat cooked at high temperatures will cook to fast, burn and not cook internally.

I suggest using a smoker with a comfortable amount of room in the cooking chamber.

But a hot oven will do just fine as well!

Face the fat up and away from the roasting rack.


How to Accurately Monitor the Internal Temperature

Use a calibrated meat thermometer to measure the internal temperatures.

This is the safest and most accurate way to know if meat is ready!

What Internal Cooking Temperature Does the Meat Need to Be?

Below is the temperature chart.

Based on the preferred levels of doneness.

Remember that the cooked temp of your meat can vary.

Based on things like a thicker crust, grade of beef, or pound of bone.

Internal Temperature Gradients for Doneness

Rare – 125°F

Medium – 135°F

Welldone – 155°F

Working Out the Cooking Time

To estimate the cooking time you need the exact weight and cooking temperature.

To get medium prime rib you need to cook it for 40 minutes per pound at 225°F.

This level of doneness is what works best for a prime rib due to its fat content.


Signs the Fat Cap Is Burning

– The crust has turned darker and is smoking.

– The crust is hard to the touch.

– Use your nose!

Tips for a Burning Fat Cap

– Reduce the temperature by 20°F on your cooking device.

– Cover the fat with aluminum foil.

– Spray some water into the cooking chamber if using a smoker.

Prime Rib Fat Side up or Down – The Summary

– Trim the top layer of fat to 1/2 an inch.

– Cook the prime rib fat up and facing away from heat at 225°F.

– Seal the fat as per the directions above.

– Understand the different types of fat in a prime rib.

– Monitor for burning and adjust accordingly.

Smoke On!


Hi, I’m Charlie, I have been meat-smoking and grilling for the past 15 years. I have an array of different smokers, thermometers, and have a love for finding the right wood and charcoal combo My favourite recipes are my EXTRA CRISPY smoked pork belly, juicy pulled pork, smoked brisket, duck poppers, and ANY SEAFOOD I grill).

I loves sharing his tips with beginners, helping them navigate the world of smoking. I find it’s not just about cooking; it’s a quest for that perfect smoky flavor.

You will usually find me playing with the kids, perfecting my brisket bark, or sipping beers with boys around the fire. Can’t wait to share all my delicious smoking and grilling recipes with you!

You can read more about me on our About Us page.

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