How Long To Cook Prime Rib At 225°F

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Cooking your prime rib at a temp of 225°F? Perfect! Cooking prime rib low and slow is the optimal way to do it!

Wondering how long you need to cook it to get it to your desired doneness?

Below you’ll see exactly how long you need to cook your prime rib.

How Long to Cook Prime Rib at 225?

It takes 2 – 3.5 hours to cook an average-sized prime rib roast to medium rare at 225°F. When I am smoking a prime rib on my pellet grill I usually allow 30- 45 minutes per pound. However, I always use a temperature probe to monitor the internal temps. I have also included the timings for other levels of doneness, because to everyone likes medium rare.

How Long to Cook Prime Rib At 225°F Per Pound For Medium 

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

This level of doneness is what I usually go for. 

As there is still a pink center and the fat has time to render.

How Long to Cook Prime Rib At 225°F Per Pound For Rare

To get a rare prime rib you need to cook it for 30-35 minutes per pound at 225°F.

How Long to Cook Prime Rib At 225°F Per Pound For Well Done

To get a well-done prime rib you need to cook it for 40-45 minutes per pound at 225°F.

Example Of Cooking A 5-Pound Rib Roast Medium

Let’s say your prime meat cuts weigh 5 pounds and you prefer medium doneness. A 5-pound rib roast will take 200 minutes at 225°F. (3.5 hours)

Accurately Monitoring The Cooking Time 

Now we know how to calculate the cooking time. But how can we further ensure that we are accurate?

Know The Exact Weight 

Make sure you know the exact weight of the rib roast. This will be on the packaging if you got it in the store.

I recommend you buy fresh and free range from a butcher. Always confirm the weight with them on purchase.

Meat Grading & Trimming The Fat Cap

A prime rib contains a high percentage of fat which is not a bad thing and part of the reason it tastes so good!

Prime ribs are graded on the amount of intramuscular fat which gives tastier juices and a rich flavor. The subcutaneous fat (outside cap) can stop the meat proteins from cooking.

So you want to get it trimmed to 1/2 an inch. This cut can be an expensive roast to cook. Especially if you buy USDA select prime-grade beef.

So do it right!

Bone-In Or Bone-Out?

A boneless roast contains more meat per weight than a bone-in roast.

A bone-in roast may also take longer to cook as the heat has to penetrate the rib bones. 

Factor in whether or not you are cooking bone-in or out when estimating timings.

Indirect Or Direct Heat?

225°F is a low temperature for cooking which should be done with indirect heat. This will allow for the fat and connective tissue to render.

This will result in tender muscle fibers (meat) and the reintroduction of natural juices.

Forming A Crust From The Fat Cap With Direct Heat

Remember that fat cap?

A sign of perfectly executed rib roasts is a well-browned crust.

By pan-sealing the entire roast to develop an outer crust from the fat. This locks in juices and removes surface moisture for your rib roast recipe for the ultimate roast beef-eating experience.

You can also try a reverse sear which is the same as above, just after it has cooked through!

What Internal Cooking Temperature Does The Meat Need To Be?

Below is the temperature chart before the consumption of a rib of beef 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

Resting & Carryover Cooking

Always rest meat by covering the roast in butcher paper or aluminum foil. The internal temp will raise by about 10°F during this process.This is known as carryover cooking.

Remove from your hot oven or grill a little bit before your required perfect temperature.

Keep the meat thermometer in so you can monitor it while resting.

Accurately Monitoring The Internal Temperature With A Meat Probe

Arguably the most important tool in all your cook time!

Have calibrated temperature probes to accurately monitor the internal temperature.

These are a type of digital thermometer probe you insert into them during cooking.They update you in real time for an accurate reading.

Temperature control is key for a successful cook. Remember that these timings are estimations.

Optimum Temperature Ranges

The standard temperature range is 20°F above or below your set temperature. This will depend on what you are using to cook the ribeye roast.

What Are You Using To Cook The Prime Rib At 225°F?

A convection oven or pellet smoker is best for the perfect holiday roast.

Below are some tips for slow roasting and smoking on these at 225°F.

Just remember to consider the above factors so you can be confident when serving up a holiday dinner.

Enjoy!

On A Pellet Smoker

A smoked prime rib roast is the best!

Set the temperature to 225°F.

While waiting for the temp, seal the fat for a delicious brown crust. Think about the type of wood chips you want to use.

A pellet smoker will maintain a consistent temperature within 5-7 degrees making it easier to calculate the cooking time for your favorite recipes.

Monitor the internal temperatures with the probe.

Roasting In A Conventional Oven

Set your oven to fan mode and the required temperature of 225°F.

While you wait for this oven temp, start on that nice crisp-meat crust!

Put the roast on a wire rack or baking sheet. Then place it at the top of your preheated oven.

Be careful not to keep opening the door as this can drastically reduce the heat. Monitor the internal temperatures with your probe.

Note: Oven temperatures can jump around if you open the door. Try to avoid doing so through the cooking process.

Smoke On!

Charlie

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