How to Fix Undercooked Prime Rib: What to Do and How to Avoid It Next Time

Have you finished cooking a prime rib roast to realize it is underdone?

Undercooked beef is a common mistake that happens to the best of us.

Some common mistakes include not knowing the correct internal temperature for your desired doneness to incorrectly estimating the cooking time.

But don’t worry!

Below you’ll find out exactly what to do if your prime rib is undercooked, plus some tips on avoiding it happening!

What Temperature Is Considered Undercooked Prime Rib?

For a perfectly cooked rare prime rib, cook it to a temperature of 120–125 degrees Fahrenheit; anything lower would be considered undercooked.

Medium-rare meat should be cooked until it reaches an internal temperature of 130-135 degrees.

For medium-cooked prime ribthe internal temperature should be between 135 and 145 degrees; for medium-wellit should range from 145 to 155F.

A well-cooked steak should have an internal temperature of between 155-165 degrees. To ensure the prime rib is cooked properly, you need to be aware of the cooking temperature.

A Step-By-Step Guide For An Undercooked Prime Rib

Prime rib is one of my favorite cuts of meat to cook. There is versatility in how you can prepare and serve the recipe.

The leftover meat also goes well in a sandwich with delicious horseradish sauce! But more creativity means a higher chance of undercooked meat.

The internal temperature for rare meat is 120-125 degrees. So anything below these temperature ranges is ice considered undercooked.

Step 1 – Accurately Confirm The Internal Temp

Always use a meat thermometer to know if meat products are cooked.

Insert the probe into the thickest part of the meat. Avoiding the bone if your prime rib has one.

If you have a reading of 110°F then you can remove and rest covered with foil. The carryover cooking will raise the temp by 10°F when resting.

Tip: Resting is an important part of the cooking method. Do not neglect this stage and allow for the temperature increase.

Note: We have seen a baseline for the temperature range of rare meat in beef. If you prefer medium doneness or above then follow step 2.

Read further for the exact doneness temp ranges in cuts of beef.

Step 2 – The Internal Temp Was Lower Than 110°F & How To Fix It

Below is the traditional method to apply to undercooked meat. Simply just continue cooking it as before until it is at the temp you prefer!

– Ensure a calibrated meat probe is inserted into the prime rib.

– Place back into the oven or smoker at the same cooking temp.

– Cover with foil if the outside fat cap looks like it might burn.

– Monitor until your required degrees of doneness.


Why Your Prime Rib Is Undercooked (And What To Do About It)

Now we understand how to get perfectly cooked beef from it being underdone. Let’s explore how we can plan and prevent this in the future!

The Weight Of The Piece Of Meat Was Wrong & So Were Your Cooking Calculations

As we covered, an oven-safe meat thermometer is the best way to know if meat is cooked.

But also estimating a rough cooking time will give you guidelines to follow throughout the key stages of the cooking process. This will help you realize if your meat isn’t cooking per your timings.

You Didn’t Trim The Fat Cap

There is a large fat cap on the prime rib which needs to be trimmed to 1 inch. Ask your butcher to do this for you or use a sharp knife.

Thick subcutaneous fat will deflect heat energy. Which means it slows down the cooking process!

The Cooking Method

As we said, slow cooking at 225°F is best! A large cut of meat cooked at high temperatures will burn and not cook internally.

I suggest using a smoker with a comfortable amount of room in the cooking chamber. This allows the heat to render the fat and penetrate the meat.

But a hot oven will do just fine as well!

Faulty Meat Thermometer

Don’t rely on just one thermometer for your recipes!

They can break after heavy use or become faulty due to an inaccurate reading. Calibrate this useful tool before use.

Calibrating A Food Thermometer

– Fill up a glass of ice and top it with water.

– Wait 3 minutes.

– Insert the probe into the water at the bottom of the glass.

– Check the reading for 0°F – 5°F.

– If above and stagnant there is a fault.

Internal Temperature Gradients For Doneness

Below are the correct temperatures for your required doneness in a prime rib measured in Fahrenheit (°F)!

Rare – 120 – 125 degrees on a meat thermometer.

Medium – 130 – 135 degrees on a meat thermometer.

Well done – 155-165 degrees on a meat thermometer

Estimating The Cooking Time For A Prime Rib

To estimate the cooking time you need exact weight and cooking temperature. The best temp to cook a prime rib is low and slow at 225°F.

Do this in an electric pellet smoker or conventional oven.

Calculating The Cooking Time At 225°F

A prime rib cooks at a rate of 40 minutes per pound at 225°F for medium.

Food Safety Advice To Avoid Harmful Bacteria In Undercooked Meat

Raw meats contain illness-causing bacteria. Below is some quick advice to stop any gastrointestinal illnesses from beef.

– Do not leave the prime rib between 40°F – 140°F for longer than 30 minutes.

– Pay attention to surfaces and utensils that have had contact with raw meat.

– Use a calibrated meat thermometer to measure the internal temperature.

Smoke On!


Author: Charlie Reeves
Hi, I’m Charlie, I am head taste tester at Simply Meat Smoking! I love it grilling, smoking, and getting out in the yard with the kids! The family also love to test all my recipes (especially my EXTRA CRISPY pulled pork, smoky pork loin, and ANY SEAFOOD I grill)

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

You can read more on our About Us page.

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