How to slow cook a prime rib roast

During holidays and special occasions with lots of guests, there’s a ton of pressure to get things right. So here’s everything you need to know about making a stunning prime rib roast.

1. Meat selection
2. Why is prime rib so expensive?
3. What’s the cost of a rib roast?
4. Choosing a grade of beef
5. How much to buy
6. Whole roast vs. smaller roast
7. Leave the bone on
8. Score the fat on top
9. Season, ideally overnight
10. The slow roasting method
11. How long does it take to cook?
12. The benefits of resting meat
13. Brown the surface just before serving
14. Carve the prime rib
15. Other ways to flavor the crust
16. Serve this with
17. FAQ
18. Prime Rib Recipe

Nothing is more impressive than presenting your guests with slices of perfectly roasted prime rib. But when you’re in charge of cooking, this can be a bit intimidating. This cut of beef isn’t cheap, so you don’t want to mess it up. The key is not to rush the process. Make sure to factor in at least 5 hours the day of your party to ensure serving dinner on time.

The technique involved is very similar in theory to my reverse-seared steak recipe, but on a larger scale and using just the oven. The goal is to nail a medium-rare, warm pinkish-red center right when you slice it. My method achieves a more even coloration and doneness throughout the roast. I also wait to brown the meat’s exterior in the oven for a delicious crust right before serving.

Meat selection

I recommend purchasing a bone-in rib roast. The bone doesn’t affect the flavor because it sits on the bottom, but it acts as an insulator to better regulate the heat. The roast’s bones prevent cooking too quickly or drying out and yield tender, juicy pieces. The bones are also tasty to chew the meat from, and you can use them to make a stock, soup, or sauce later.

You can purchase a boneless rib roast, but it will cook faster. If using, make sure to elevate it on a wire rack so there isn’t direct contact with the pan’s hot bottom for even cooking.

Why is prime rib so expensive?

When purchasing a rib roast or standing rib roast from the store, you might get a little sticker shock. It’s because it comes from a very tender portion of the cow, where less muscle is used, and there is a good amount of fat or marbling in the meat. This type of beef cut comes for the upper rib section from a specific seven-bone location. 

No matter what, prime rib is a pricey cut compared to single portion steaks. Most stores won’t fabricate and sell them until closer to the holidays. In fact, when developing this recipe, I had to call to have the butcher cut the rib roast for me. They were happy to do so, therefore don’t be afraid to ask if you don’t see one sitting in the refrigerator section of the meat aisle.

What’s the cost of a rib roast?

When on sale, Choice cuts can be around $7 a pound, to upwards of $16. Prime starts at approximately $17 per pound, and if you want incredibly tender and dry-aged flavor beef, it’s about $20 per pound.

Choosing a grade of beef

You typically have two options; Prime or Choice grade of beef. The main difference is the marbling or the amount of intramuscular fat that’s white and visible. As the fat melts during cooking, it flavors the meat and makes it tender. 

• Prime: The highest quality of beef as graded by the USDA. It has a heavy marbling, between 10 to 13%. You will have to make a trip to a butcher or higher-end store for this.
• Choice: Less marbling, a moderate level for good flavor, which you can find at most major grocery retailers.

Prime is noticeably better if you are willing to spend about 25% more. Although compared to going out to an expensive steakhouse, you’ll be able to feed a crowd and have side dishes for a comparably lower price.

How much to buy

For a bone-in rib roast, factor about 1 pound per person. For a boneless roast, calculate ¾ of a pound per person. These amounts should be plenty of meat. If you’re lucky, you’ll have leftovers to make other meals like French dip sandwiches.

Whole roast vs. smaller roast

A cow has 13 ribs per side, and the rib roast cut is from the 6th to 12th bone. A whole roast can weigh between 14 to 22 pounds, which is excellent for a big dinner party. However, it’s often cut in half, with 3 to 4 bones per roast, about 7 to 11 pounds, which is more manageable for a smaller party.

If you can request the “first cut” or “loin end” or “small end” from ribs 10 through 12, that is closer to the loin portion, I prefer this cut. This section has a uniform ribeye muscle that’s more tender and less fatty. The “second cut” or “large end” from bones 6 to 9 is closer to the chuck end and the shoulder. This section has more muscle variety, connective tissue, and fat. It’s not as uniform but has a good flavor from the fat.

Leave the bone on

To prepare the prime rib for a stunning presentation, leave the bone attached to the meat. I find that fewer juices are lost during the cooking process, keeping it moister. It also acts as a raft, elevating the beef on the rack for even cooking.

If you want to make carving easier later, you can cut the meat away, then tie it back onto the bone after seasoning. But I figure this saves you an extra step, and it’s not hard to cut the meat off the bone after resting.

Score the fat on top

For a super flavorful roast, leave at least ¼ to a ½-inch thick layer of fat cap. Doing so insulates and bastes the beef with the rendered fat. Before salting, make shallow scores in a crosshatch pattern, about 1-inch apart. Don’t cut into the meat, just into the fat. The slits allow more seasoning to seep through, and the fat will render down quicker.

Season, ideally overnight

Like dry brining a roasted turkey, I recommend seasoning with a generous coating of kosher salt and pepper at least 24 hours before roasting. Overnight the salt has time to wick up more surface moisture which will lead to better browning on the crust.

You can place the seasoned meat in the same roasting pan set on the rack you plan to cook it in. Or you can use a wire rack set on a baking sheet. The idea is to get air circulating above and below to dry it well. The longest to let the roast brine is about 2 days. Any longer, and the surface will get too tough like jerky! It’s not required to salt in advance, but I would do it if you can.

The slow roasting method

Roasting a large piece of beef at low temperatures first has several advantages. The oven works by convection, transferring the energy from the heating element to the outside of the meat. At 200ºF (93ºC) this is a more delicate cooking process.

Yes, it takes longer, but the meat will be more pink and juicy throughout. Let the beef gently roast for several hours for medium-rare doneness. The center cooks by conduction, the heat transfers from a hotter to cooler meat section. There won’t be a golden-brown crust, but we’ll take care of that later!

How long does it take to cook?

The rib roast will take about 30 minutes per pound when cooked at 200ºF (93ºC). However, give yourself an extra 1-hour buffer. The additional time accounts for heat lost when checking the oven, needing time to get back up to temperature, and any extra cooking time. The temperature fluctuates about 6 to 8-degrees every 30 minutes after the first hour.

I highly recommend using a meat thermometer to check the center of the roast for doneness. I use my Chef’s Alarm meat probe inserted into the roast during the entire cooking process. There’s no need to keep opening the oven door and losing heat. Don’t forget to account for carryover cooking while the meat rests. There’s usually about a 5-degree elevation in temperature. Therefore stop cooking before your ideal doneness. See the chart below.

The benefits of resting meat

Don’t lose all of those flavorful juices! Let the meat rest, tented with foil, in the roasting pan, for at least 30 minutes. This duration gives the juices time to redistribute in the meat. If you don’t need to serve it right away, the meat will stay warm for up to 1 ½ hours. This is helpful if you’re still waiting for guests to arrive or there are unexpected delays.

Brown the surface just before serving

The moisture has evaporated from the surface with the roast in the oven for an extended period. This makes creating a golden-brown crust much faster and more effective. Turn the oven up to 500ºF (260ºC). It will take several minutes, but it’s just the right time between resting the meat and the final sear.

Once the surface turns a deep brown and the fat is crisp, it’s ready! About 5 to 10 minutes, just keep an eye out for color change. If you don’t want to wait so long for the oven to heat, you can broil on high. Just make sure to keep a very close eye, as the broiler elements are very hot!

Carve the prime rib

Right after searing, cut the meat along the natural curvature of the bone as close as possible to remove. Now you can slice the roast to 1/4-inch thick pieces or ½ to 3/4-inch for heartier portions. Cut in between the bones to separate so you can enjoy those too. If the meat was tied together with twine to the bone, just cut off the string and slice.

Other ways to flavor the crust

• Black pepper crust with crushed whole peppercorns
• Brush with Dijon mustard for a tangy flavor, I do this for beef wellington
• Add blue cheese, feta, or gorgonzola on top at the end of cooking
• Add homemade bread crumbs or panko for crunch
• Make an herb coating with herbs like rosemary, thyme, or oregano

Serve this with

• Creamy horseradish sauce
• Mushroom gravy
• Roasted brussels sprouts
• Mashed potatoes
• Sauteed green beans
• Roasted asparagus

FAQ

What cut of meat is a prime rib?

It’s a large and specific section of the rib, seven bones cut from ribs 6 through 12. It’s sold as a whole roast or often cut in half into 3 or 4 ribs. It yields very tender and flavorful meat when slowly cooked for several hours on low heat.

Is prime rib the same as ribeye?

They come from the same primal section of the cow called the beef rib. Prime rib is slow-cooked, usually with the bone or boneless, as a large roast to feed a crowd. Ribeye is portioned into individual steaks and cooked more quickly with a golden sear on the surface.

What is a prime rib called at the grocery store?

At the grocery store, it’s called “rib roast” or “standing rib roast” because it has bones. Boneless rib roasts will have the bone removed.

How do you buy prime rib?

Purchase a whole rib roast with seven bones when serving 14 to 22 people. Select a half rib roast, 3 to 4 bones for 7 to 11 servings. Some butchers trim the fat off and cut the rib from the meat, then attach it back with twine for roasting.

What’s the difference between prime rib and rib roast?

Rib roast or standing rib roast is the name of the cut. It yields very tender and juicy slices of rib called prime rib when slow roasted.

Do you need to truss the rib roast?

Not if the bone is still attached, the meat will hold its shape. Only tie with butcher’s twine if the grocery store trimmed the meat from the bone and you are reattaching before roasting. You do not need to tie a boneless roast.

The benefits of slow-roasting

Cooking for several hours in the oven at 200-degrees activates enzymes called calpains and cathepsins. They help break down meat proteins to create a more meaty, umami taste and soft texture. The activity happens below 122ºF (50ºC), so the longer the meat is held below that temperature, which is about medium-rare before resting, the tastier the beef.

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• ▢ 7 to 11 pounds bone-in standing rib roast, 3 to 4 ribs, about ½-inch thick fat cap
• ▢ 2 tablespoons kosher salt
• ▢ 1 teaspoon black pepper

• Use a sharp chef’s knife to cut a shallow crosshatch pattern about 1-inch wide into the fat cap on top of the roast. Do not cut into the meat!

• In a small bowl, combine the salt and pepper. Generously sprinkle the seasoning over the fat, sides, and rib bones. Transfer to a roasting pan on top of the rack or a cooling rack set on a sheet pan. Refrigerate, uncovered, for at least 24 hours, up to 2 days.

  Alternatively, you can season the meat the same day as cooking for quicker preparation.

• Set the oven rack to the lowest position. Heat to 200ºF (93ºC). Place the rib roast in the oven and cook to just below the desired serving temperature. Cooking time is approximately 30 minutes per pound.

  For more accurate results, use an instant-read thermometer and remove the roast when the meat's center registers 115 to 120ºF (for rare), 120 to 125ºF (for medium-rare, 130 to 135 (for medium), 140 to 145 ºF (for medium-well), and 150 to 155ºF (for well done).

• After removing the roast, loosely tent it with foil and allow it to rest for at least 30 minutes or up to 1 ½ hour. Keep the oven on.

• While the meat rests, or 30 minutes before serving, increase the oven temperature to 500ºF (260ºC). Remove the foil and brown the crust, about 5 to 10 minutes. Keep an eye on the color change for burning.

• Transfer to a cutting board and carve right away. Cut the meat as close the bone as possible, following the natural curvature of the rib. Slice into ¼ to 3/4-inch thick slices. Serve immediately while still warm.

• Checking meat temperature: Avoid excessively opening the oven door. It will take about 10 minutes to get back to 200ºF (93ºC), increasing cook time. 
• For more even meat doneness throughout: Remove the roast from the refrigerator and let it stand on the counter at room temperature for 2 to 3 hours before roasting.

Nutrition Facts

Prime Rib

Amount Per Serving

Calories 947 Calories from Fat 756

% Daily Value*

Fat 84g129%

Saturated Fat 35g175%

Polyunsaturated Fat 3g

Monounsaturated Fat 37g

Cholesterol 192mg64%

Sodium 839mg35%

Potassium 704mg20%

Carbohydrates 1g0%

Fiber 1g4%

Sugar 1g1%

Protein 43g86%

Vitamin A 1IU0%

Calcium 25mg3%

Iron 5mg28%

* Percent Daily Values are based on a 2000 calorie diet.

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