Cooking a Prime Rib Roast

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When cooking a prime rib roast, you’ll soon discover that it is one of the easiest meats to cook. Prime rib also fits in with the best of special occasions and is considered one of the most elegant entrees of all.

There are two primary methods to use when cooking a prime rib roast: medium heat and searing. Both use an oven temperature of 325 degrees F. The only difference between them is that with the searing method, you’ll first “sear” the meat in an oven at 450 degrees F for about 20 minutes before turning the oven down to 325 degrees F for the rest of the cooking time.

Here’s a more complete description of each of the two methods:

Medium Heat Method 

Place rib roast in roasting pan, fat side up. Add salt and pepper if desired. Generally a coarser salt is used for prime rib, such as rock salt or possibly coarse sea salt. Sometimes kosher salt is used. If you’re adding an herb rub, add the rub after the salt.
Bake roast for specified amount of time at 325 degrees F according to table below plus an additional 25 minutes.

Searing Method 

Place rib roast in roasting pan, fat side up. Add salt and pepper if desired. Generally a coarser salt is used for prime rib, such as rock salt or possibly coarse sea salt. Sometimes kosher salt is used. If you’re adding an herb rub, add the rub after the salt.
Sear roast for 15 minutes at 450 degrees. Bake roast for specified amount of time at 325 degrees F. See table below.

Should You Rub or Not? 

Prime rib is one of the tender cuts of meat that really doesn’t need any additional flavor; however, you can always add an herb rub or just plain old salt and pepper to the meat prior to cooking.

Here are a few ideas for different rubs:

Italian rub:
2 tablespoons fresh each oregano, basil, parsley, garlic
5 tablespoons olive oil
1/2 cup rock salt (rub this on roast first before herbs)

Chop herbs finely, Add all ingredients together. Rub into meat.

Garlic Wine rub:
Use a food processor to blend these into a smooth paste:
8 cloves garlic
3/4 cup onion
1/4 cup fresh parsley
2 tablespoons fresh grated horseradish
2 tablespoons fresh oregano
2 tablespoons flour
1/4 cup light mayonnaise
1/2 cup dry red wine
Rub into meat.
This rub is great to start out the cooking process. At the end of cooking, add a few cups of red wine to the pan drippings and make au jus gravy. (See below.)

The Details Matter Most When Cooking a Prime Rib Roast

There are a few more details to cooking a prime rib roast that you need to know to make the process go a lot smoother. Those details are incorporated into the next question and answer section.

Q: When I buy the roast, how large a roast should I buy for 8 guests?
A: It depends if your roast has ribs or not. Allow 12 to 15 oz. per person for a roast with bones; 8 to 10 oz. per person for a roast without bones.

Q: I notice that it’s possible to buy the roast with ribs or without. Which is better?
A: Either way is fine. The advantage of buying one with the rib bones is that you can use the rib bones as a little rack to set the roast on during cooking. To do this, cut the rib bones off the roast as you prepare the meat.

Q: What can be served along with prime rib roast? I need some ideas.
A: Horseradish is a must. People love horseradish with their prime rib roast. You can buy this at the store or make your own.

To make your own horseradish sauce, finely grate about 3/4 cup fresh horseradish. Add grated horseradish to 2 cups sour cream, heavy cream or plain kefir milk. Add two tablespoons fresh lemon juice and a teaspoon of salt. Mix and refrigerate.

Vegetables that go well with prime rib roast are the vegetables that are asparagus spears, broccoli spears, corn on the cob, and carrots cut lengthwise, not diagonally.

Don’t forget a nice dessert – this one’s up to you!

Q: About how long should a prime rib roast be cooked?
A: Allow about 17 to 19 minutes per pound of roast; a 10 lb. roast would be cooked for a little under 3 hours.

Q: Are there more specific cooking guidelines for roasts of every size?
A: I always start out with a roast of 10 pounds, then adjust it from there. Here’s a quick chart:

Roast Weight Searing Time at 450 degrees F Baking Time at 325 degrees F
10 lb. roast 15 minutes up to 2-1/2 hours
11 to 13 lbs 15 minutes up to 3-1/2 hours
14 to 16 lbs 15 minutes up to 4-1/2 hours
Less than 10 lb Less than 10 lb 15 minutes up to 2-1/4 hours

Remember that the meat is medium rare done when the internal temperature reaches125 degrees F.

Q: I understand that prime rib should never be cooked more than medium rare. Why is this and what do I do if my guests want medium well done? 

A: One chef’s trick is to pour piping hot juices over the meat which will help cook it a little more. If you need it done more than that, you may want to pan fry it for a few minutes. Sometimes home chefs may carve the meat, taking the medium rare slices, then placing it back in the oven for those who prefer it to be done longer.

Q: What’s an easy way to make an au jus? 

A: When the meat comes out of the oven, pour a bottle of red wine into the roasting pan. Then strain out the pan drippings, cook down the liquid until it thickens and you’re good to go!

With this information, you and your guests will enjoy your first prime rib roast! Expect great flavor!

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