How to Cook Prime Rib?

How to Cook Prime Rib

For an absolutely delicious main dish that will impress your family and guests, nothing beats a well-made prime rib! And learning how to cook prime rib is one of the easiest kitchen tasks you will ever attempt! If you follow these easy steps, you really can’t goof up! Let’s start with what you will need:


  1. A Rib Roast
  2. ½ Cup Kosher Salt
  3. ½ Cup Cracked Black Pepper
  4. ½ Cup Rosemary


  1. Trim excess fat from roast (if desired) but leave a thin layer to baste the roast.
  2. Mix together salt, pepper, and rosemary.
  3. Apply the mixture to the outside of your prime rib to make a crust.
  4. Put the roast in a 2 to 3 inch high baking pan.
  5. Insert a meat thermometer into the roast with the tip near the center -OR- have an instant thermometer handy.
  6. Preheat the oven to 450°F/232°C. Cook roast at this temperature for 15 minutes to sear the crust.
  7. Reduce heat to 325°F/163°C

Cooking Times

While many recipes for prime rib use the “slow cook” method, we will be using a faster method. This is especially important with prime rib because the internal temperature of the meat never reaches 165°F/74°C (the temperature where all bacteria is killed) unless you want a dried out hunk of meat. This “fast cook” method reduces the cooking time considerably and, therefore, reduces the amount of time that any bacteria can grow in the meat. This is most important when cooking prime rib rare and medium rare!

Due to variables like oven accuracy, exact roast weight, and others, it requires a few steps to determine how much longer you will cook your prime rib in order to get it done exactly the way you want it. The following chart will give you the approximate cooking times for rare prime rib. At those times, you will want to start checking the internal temperature of your roast for the exact cooking time.

Start Checking Internal Temperature Times

# of Ribs

Weight (Pounds)



7 to 8

1¼ to 1½ hours


9 to 10

1½ to 2 hours


11 to 13

2 to 2½


14 to 16

2¾ to 3 hours


16 to 18

3 to 3¾ hours

Note: You will only need to add about 15 or 20 minutes to the times above for “well done”. This is why determining the internal meat temperature is so important! From rare to well done is only a very short amount of time! Now you will use the meat thermometer to guarantee a perfect prime rib! See the chart below for proper internal meat temperatures:

Internal Meat Temperature Chart





Red Center-Very Pink Near Outside


Medium Rare

Very Pink Center To Slightly Brown



Barely Pink Center To Brown


Medium Well

Light Brown Center To Dark Brown


Well Done

Dark Brown Throughout


Finishing Touches

Your prime rib should be allowed to rest out of the oven but in a warm place for 30 minutes before serving. This will allow the meat to become even more tender and the flavor in the crust will better flavor the roast. If you want to keep the meat hot, place a tent of aluminum foil over the meat to seal in the heat. When using the foil tent, you may want to reduce the internal meat temperatures above as the prime rib will actually heat up another 5°F/-15°C or so from the heat of the baking pan.

For an absolutely delicious sauce to compliment your prime rib combine the following ingredients. You can make 2½ cups of this sauce up to two days before serving! Just keep it covered in the refridgerator.

  1. From ¼ to ½ cup of prepared horseradish (Depending on how spicy you like it)
  2. 2 cups light or regular sour cream
  3. 2 tablespoons of lemon juice
  4. 1 teaspoon of salt

Thank you for visiting our How to Cook Prime Rib post!