Introduction: Pat LaFrieda's Ultimate Prime Rib Guide

The Prime Rib, or Standing Rib Roast, is the king of the roasts. A well prepared high quality Prime Rib will be remembered for months to come. However, many people find the task of cooking a Prime Rib a daunting one. These roasts can weight upwards of 18 lbs and it's challenging to cook them evenly to the desired doneness. Don't worry. The techniques we present in this guide are straightforward and precise.

Where to Buy a Prime Rib

You can usually find a "choice" grade Prime Rib at your local butcher shop and some supermarkets. Higher end markets will usually carry some "prime" grade Prime Ribs around the holidays. Beware of frozen Prime Ribs. Unfortunately, some purveyors buy Prime Ribs in the off-season and freeze them for up to 10 months.

You can also order fresh, never frozen, "prime" grade Prime Ribs directly from our website We carry both non-aged and aged Prime Ribs all year round.

Our Criteria
A perfectly cooked Prime Rib should meet the following criteria:

  1. The roast should not be left out for hours to bring it to room temperature because some bacteria leave behind toxic proteins when they multiply (e.g. staph) that can't be cooked away.
  2. The roast should have a properly seasoned and well-formed crust.
  3. The roast should be evenly cooked throughout. The entire rib eye should be cooked to the same doneness.

Who is Pat LaFrieda?
We are a family run business of meat purveyors since 1922. Our core business is supplying meat to the top restaurants in NYC and the surrounding areas. We are well known and respected in the meat industry. Restaurants proudly display our name on their menus. Many people also know us from our Food Network show Meat Men.

Other Guides
There are a number of recipes/guides for cooking Prime Rib that already exist. Unfortunately, we have found that they suffer from one or more of the following three shortcomings. One, they do a reasonable good job on small roasts (e.g. 2 ribs), but ruin large roasts (e.g. 4-7 ribs). Two, they do not correctly account for carryover cooking which leads to an imprecise result. Three, they suggest leaving your roast out for up to ten hours beforehand, which is incredibly unsafe.

What You Will Need
Cooking tools:

  1. A roasting pan (wider than the roast)
  2. A roasting rack
  3. An oven safe probe thermometer (recommended) or quick read thermometer

Ingredients for roast:

  1. Standing rib roast, cold
  2. Room temp butter (quantities below)
  3. Freshly ground black pepper (quantities below)
  4. Herbs, your preference, e.g. Herbs de Provence (quantities below)
  5. Salt (quantities below)

Ingredients for au jus:

  1. Beef stock (quantities below)
  2. Flour (quantities below)
  3. Pan drippings (quantities below)
Ingredient Amounts:
Ingredient Prime Rib Size
3 ribs 4 ribs 7 ribs
butter (oz) 3 4 8
pepper (tbsp) 1 1 1/2 3
herbs (tsp) 1 1/2 2 4
salt (tbsp) 2 1/2 3 6
beef stock, low sodium (oz) 6 8 16
flour (tbsp) 1/3 1/2 1
drippings (cups) 1/4 1/3 1/2

Quick Directions
We will explain the following steps in depth, but here is a quick summary:

  1. Choose an appropriately sized roast (2 people per rib). Choose amount of dry aging based on preference and doneness. Recommendation: Rare - 50 days, Medium-Rare - 30 days, Medium - Fresh (no aging). Have your butcher bone and tie the roast for easy slicing or french and tie the roast if serving on the bone.
  2. Mix soft room temp butter, pepper, and herbs. Remove roast from fridge and cover the entire roast with the mixture. Now sprinkle the salt all over the roast, but use a very light application over the ribs and ends.
  3. Put roast on roasting rack and place in roasting pan. Insert roast into a pre-heated 450°F oven. The cooking time of this phase depends on the size: 30 minutes for 3-4 ribs and 45 minutes for 7 ribs.
  4. Turn the oven down to 250°F and cook the roast for another 30 minutes.
  5. Remove roast from oven, but do not turn off. After a 30 rest, return the roast back to oven.
  6. The roast needs to cook at 250°F until the center of the roast is 15°F below the target temperature: 110°F for rare, 115° for medium-rare, 125°F for medium (carryover cooking will add 15°F to these). The easiest way to determine this is to use a probe to monitor the internal temperature. Alternatively, you can use a quick read thermometer to occasionally measure the temperature. The center will cook ~1°F every two minutes. (I.e., if you have 20 degrees to go, then you need about 40 minutes.) (This step typically takes about 60-90 minutes for rare, 70-100 minutes for medium-rare and 90-120 minutes for medium.)
  7. Remove the roast from the oven, wrap in foil and let it rest for 30 minutes. Remove the roast from foil and let it rest another 15 minutes. Make an au jus from the pan drippings (as described in this guide).
  8. Slice the rib as desired and plate. Serve with au jus.

Step 1: Choosing a Prime Rib

There are four things to decide when choosing a Prime Rib: grading, size, age, and preparation.

The term "Prime Rib" only refers to the cut, not the grading of the meat. Meat is graded solely on its fat content. Prime meat contains the most amount of intermuscular fat. We highly recommend going with Prime Black Angus Beef.

Collagen, the protein that holds meat together, only just begins to break down at 125°F. The more rare you cook meat, the tougher it will be. This toughness can be offset by using dry-aged beef. Dry-aging beef tenderizes meat and condenses its flavor. The following chart shows our suggestions for selecting a proper age for your roast.
Doneness Dry Age
Fresh 30 Days 50 Days

The general rule of thumb is that each rib will feed two people. For example, a 4-rib roast should feed 8 people.

Prime Ribs typically come either frenched and tied or boned and tied. The image above shows a frenched and tied roast which is preferable if you want to serve it on the bone. However, a boned and tied roast is much easier to slice. Once cooked, the bones easily come off when the butcher string is cut. Once boneless, the roast can be sliced to any thickness.

Step 2: Seasoning the Roast

The Prime Rib is a huge hunk of meat, and therefore requires a large amount of seasoning. Also, consider that once you slice the roast, there will be just a thin band of seasoned crust around each slice. It's difficult to get the appropriate amount of seasoning to stick to the roast, so we use a trick that we learned from Chef John at Food Wishes. We mix pepper and herbs into soft room temperature butter and cover the Prime Rib with it. This will allow copious amounts of salt to stick to the surface of the roast.

For salt, we prefer to use smoked Maldon Sea Salt. However, kosher salt will work just fine. For herbs, we suggest using an herb blend like Herbs de Provence. The flavor that the herbs add is very subtle on the plate, but they will fill your home with an amazing aroma during the cooking process.

Mix the soft room temperature butter, black pepper and herbs. Use a paddle, spoon or brush to coat the surface of the Prime Rib with the mixture. Generously salt the top and front of the Prime Rib. Very lightly salt the back (over the ribs) and the ends. You do not want the end slices or the ribs to be too salty.

Ingredient Prime Rib Size
3 ribs 4 ribs 7 ribs
butter (oz) 3 4 8
pepper (tbsp) 1 1 1/2 3
herbs (tsp) 1 1/2 2 4
salt (tbsp) 2 1/2 3 6

Step 3: Virtual Sear

These next four steps are accompanied by graphs of the temperature of the roast in 3 key locations.

  1. Surface - The temperature at the surface of the roast. Probe is inserted just under the surface. This is represented by the red line in the graph.
  2. Rib Eye Cap - The temperature of the Rib Eye Cap. Probe is inserted about 1/2" in from edge. This is represented by the green line in the graph.
  3. Rib Eye - The temperature at the center of the roast. This is the internal temperature of the roast. Probe is inserted at the center of the roast. This is represented by the blue line in the graph.
Virtual Sear
Searing is one of the most important and necessary steps in cooking steaks or roasts. It is during the sear that the Maillard Reaction occurs, turning the surface of the meat into a delicious crust. Due to the complex shape of the Prime Rib, it is not possible to apply traditional pan searing. Fortunately, we can achieve similar results by roasting the Prime Rib in the oven at a high temperature for a short duration. We refer to this as a virtual sear.

Preheat oven to 450°F. Place the roast ribs-down into the roasting rack, over a roasting pan and place into oven. Cook at 450°F for the amount of time shown in the chart below. Then, turn the oven down to 250°F and cook for another 30 minutes. You'll notice in the graph that the surface of the roast reaches almost 200°F. This is exactly what we are looking for to produce the Maillard Reaction. In addition, this is well above the temperature needed to kill any surface bacteria.

Roast Size Time @450°F Time @250°F
3 ribs 30 min 30 min
4 ribs 30 min 30 min
7 ribs 45 min 30 min

Step 4: Post-Sear Rest

The post-sear rest is one of the unique features of our cooking method for steaks and roasts. After the sear, there is too great of a temperature difference across roast for it to cook evenly. To rectify this, we rest the meat for 30 minutes to allow the temperature to equalize. The temperature difference that we care about is the difference between the rib eye and rib eye cap (the green and blue lines in the graph). At the start of the rest there is a 40°F difference. Due to the rest, this difference decreases to less than 20°F into the next step. There are no food safety concerns during this rest because the surface temperature of the roast reached almost 200°F in the previous step, killing any surface bacteria.

Remove roast from oven to allow the temperature across the roast to equalize. Return the roast to the oven after 30 minutes. Do not turn oven off because it will likely take more energy to reheat the oven than it would to maintain 250°F. Do not cover the roast.

Step 5: Roast

The Prime Rib has a nice sear and we have rested it to allow the temperature to equalize. Now, we just need to bring the internal temperature to the desired doneness while accounting for carryover cooking (15°F-20°F). Low and slow is the way to go. We keep the oven at 250°F and allow the rib eye to cruise to the target temperature. You'll notice in the graph above that the center of the roast, the rib eye, has been cooking at almost the same rate since the end of the sear. Cooking at a higher temperature will not speed up the process much, but it will overcook parts of the roast.

This step can not be done accurately by cooking time alone because every oven is different and because cooking times vary for each individual Prime Rib. The only accurate method is to monitor the internal temperature.


Cook the roast at 250°F until it reaches the desired temperature accounting for 15°F of carryover cooking. The chart below shows the suggested target temperatures for the different levels of doneness. To accurately cook the roast we need to monitor the internal temperature using one of the following two methods.

Doneness Target Temp Final Temp
rare 110°F 125°F-130°F
medium-rare 115°F 130°F-135°F
medium 125°F 140°F-145°F

Method #1

Use an oven safe temperature probe to monitor the internal temperature of the Prime Rib. These probes typically have an alarm that can set to alert you when it is done. We recommend this method. The approximate roasting time is shown in the chart below.

Method #2

Use a quick read thermometer to occasionally check the temperature of the roast. During this phase, it takes about 2 minutes to cook 1°F. You can use this to determine when to check the roast. For example, if the roast has to cook another 15°F before it reaches the target temperature, then you check it in 30 minutes. The approximate roasting time is shown in the chart below.

Doneness Approximate Roasting Time
60-90 minutes
70-100 minutes
90-120 minutes

The approximate roasting time for a 3, 4, and 7 rib roast are about the same. These times are only provided to give a general sense of how long this step takes. Always go by temperature.

Step 6: Final Rest / Prepare Au Jus

At this point, there is more than enough residual heat in the roast to finish cooking it. Applying any more heat will overcook parts of the roast. By resting the roast, we stop cooking the outer layers of meat and allow the center to catch up. The temperature at the center of the roast, the blue line in the graph above, steadily increases at about the same rate during the rest as it did while the roast was still in the oven. This is carryover cooking and it is clear from our graphs that it is a significant part of the cooking process.

Remove roast from oven and wrap in foil. Let it rest for 30 minutes. Then, remove foil and rest for another 15 minutes. While the roast is resting, prepare an au jus from the pan drippings.

Au Jus
The one shortcoming of a Prime Rib is that there is no way to season (salt) the inside of the meat. However, serving it with a simple au jus solves this problem. Au jus is easy to make.

  1. Pour the pan drippings (quantities below) into a pot or sauce pan. Heat the drippings over medium heat.
  2. Whisk in flour (quantities below). Cook for 3 minutes to remove raw flour taste.
  3. Slowly stir in beef broth(quantities below). Reduce for another 3-4 minutes or until desired thickness (should be thin).
  4. Add salt to taste. Should be slightly salty. Keep warm until served, but do not reduce any further.
Ingredient Prime Rib Size
3 ribs 4 ribs 7 ribs
beef stock, low sodium (oz) 6 8 16
flour (tbsp) 1/3 1/2 1
drippings (cups) 1/4 1/3 1/2

Step 7: Slice, Plate and Serve

Once you slice the Prime Rib, it will quickly cool to room temperature. Therefore, it is best to wait until the last moment to begin slicing. Make sure all of your guests are seated and all of the side side dishes are laid out. Also, only cut what you need for the first serving.

Frenched and Tied
Cut the butcher string and carefully remove it from the roast. If you have changed your mind and would rather slice a boneless roast, it is easy to do. Just cut along the back of the roast along the ribs and follow the bone. To slice bone-in, it is best to cut on either side of each rib. This will give you alternating bone-in and boneless slices. The bone-in slices will be larger portions.

Boned and Tied
Cut the butcher string and carefully remove it from the roast. The ribs will easily detach from the roast. Slice the roast at the desired thickness. We prefer thick slices of about 3/4".

Don't forget to serve the au jus with the prime rib. Serve this in individual ramekins or in a gravy boat.