There is nothing more impressive than a slow roasted, deeply crusted, perfectly cooked prime rib landing squarely in the center of a full dinner table.
Prime rib might be the perfect cut of beef. It’s got a little something for everyone. Intense well-marbled fat forward hits for the fat-is-flavor stans (that’s me). Supple, rosy tender parts for the filet/tenderloin fans. Savory beefiness in bulk for the ribeye-is-king crowd. And, last but not least, a deep dark crust for those guys who need to insert Maillard reaction into any conversation involving beef.
Prime rib’s reputation has taken a hit in recent decades, but as always, the old ways are the best way. Prime rib is not only the tastiest cut of beef you can buy, it’s also one of the cheapest. In this ultimate guide to prime rib, I want to convince you to bring prime rib roasts back into your life, all year round, at home where it’s best.
What is prime rib
Prime rib is one of the largest cuts of beef you can buy as a normal home cook. You buy it as a roast made of a full rack of 7 ribs. These ribs are commonly spoken of as being from ribs #6-#12. The best way to think of a prime rib is a super high quality tomahawk or bone-in ribeye, stretched out to a foot thick. It’s true: the meat that comes in a prime rib roast is the same stuff you make ribeyes and tomahawks from.
Prime rib roast
Did I say stretched out a foot thick? Yes, a prime rib can actually be closer to 24 inches thick, although you don’t have to opt for the full rack. Any good butcher will cut you whatever thickness you need.
If you can, you should go for broke and get the full rack because it’s way cheaper than individual steaks of the same quality. A prime rib roast can be split into steaks if you’re so inclined. Even if you are only cooking for 2 people, you can buy a whole rack for cheap and split it up into seven 2” thick steaks for much less than you’d pay if you’d just bought steaks.
But, the whole point of a prime rib is to roast it to perfection, with a deep dark crust and tender, rosy pink insides, so I recommend you grab a 2-4 rib segment (or more if you want) and go to roasting town. Roasting is way easier than cooking 7 steaks and so much more impressive too. In this post, I’ll show you how to do it perfectly, every time.
How to make the best prime rib
I’m going to lay it out there before anything else: to make the best prime rib you can make, use a meat thermometer. Below I’ll lay out some quick formulas and good techniques, but if you’re cooking a $100+ piece of meat, you should consider investing in a good meat thermometer. Every oven is different and every roast goes in the oven at a different temp, so a meat thermometer is essential.
The best kind for this sort of thing is a leave in meat probe that beeps you when the target temp is heat. The probe your oven probably comes with is a great option too. But even if all you have is an instant read thermapen, it’s better than nothing.
Parts of a prime rib
Prime rib looks like just one big homogenous hunk of meat, but it’s three delicious parts with their own taste and tenderness:
- Spinalis dorsi aka rib cap: This is considered a well kept chef’s secret: the greatest cut of steak, bar none. All the complexity of a flank steak, the fatty marbling of a ribeye, and the tenderness of a filet, in one steak. This cut is separated from the main body of the prime rib by a large layer of fat. Back when people vilified fat, spinalis dorsi used to be cut off and saved for the butcher or kitchen so that the ribeye steak could be presented “cleaner”. These days, especially if you order a bone-in ribeye, they just leave it on. It really is the best part.
- Ribeye: This is the main body of a slice of prime rib. It’s literally the same as a ribeye steak. It will be well marbled, tender, and complex tasting.
- Iliocostalis: Some people liken this to a long thin tenderloin. It’s also called the lip or nose of a prime rib. It doesn’t have a good reputation because it’s often smaller, fattier, and not very toothsome, but I think it’s an intensely beefy and tender cut because it sits right next to the bone. Iliocostalis used to be cut off and not served with the prime rib, as it wasn’t considered ‘prime’ enough, but these days, most butchers will leave it on for you to decide on. I recommend you leave it on.
Why make prime rib?
But why go to all this trouble instead of just getting seven steaks? Because, prime rib is intensely delicious. It’s basically the cheapest bone-in ribeye you can get at an extremely high quality for price ratio. Done right, it’s easy, forgiving, impressive, and satisfying. The best part is the leftovers can be reheated as some of the best steaks you’ll ever have.
Prime rib cooking time
If you are cooking for a hungry house and want to know how to plan on timing such a large roast to be just ready for dinner, there’s a super easy formula based on the doneless you prefer. This isn’t one of those pro-chef-speed formulas that no one can realistically achieve, it’s pretty loose with the times so you can depend on it, even if you are relaxing, drinking wine, and consulting your phone every so often for the next step of the recipe. That said, using a meat thermometer is vitally important. And, so is planning on serving appetizers and drinks before the main course for anyone who is extra hungry.
The formula is simple – assume:
- 2 hours for temper
- 30 mins for searing
- 15-30 minutes per pound (in 5 minute increments – medium rare is 20 minutes/pound)
- 30 minute rest
The prime rib that I made here was about 6 lbs, which means it was a 2 hour cook time plus 3 hours for everything else. It squarely hit the 5 hour mark from taking it out of the fridge to the first bite.
Prime rib vs steaks
Why should you make prime rib instead of steak or some other cut? Because, it’s cheaper than steak by two- to three- times, it’s easier to make, and there’s nothing more impressive than a giant roast of beef landing squarely center on the dinner table.
The advantage of steak is that you can cater to different doneness preferences, but there are so many disadvantages, such as steaks being more expensive, needing more pans (aka more dishwashing), and being so much messier, smokier, and splatterier – if you’re doing it right.
Overall, if you can justify the initial outlay, prime rib beats steak every time.
A smaller prime rib
In fact, prime rib is such a good competitor to steak that I think it’s worth it to consider a smaller prime rib, even if its just for you and your person, or even if you live alone. Ask your butcher to cut you 2-3 ribs worth. Where I live, it’s half the cost vs bone in ribeye, and my butcher sells even two ribs, which is just two bone in ribeyes stuck to each other.
When you are buying by the rib, you may get choice of which rib bones you want. The “front” is rib number 12, which is very tender with a large ribeye steak, and the “back” is rib number 6, which is more marbled and complex (some call it chuck). It’s your choice based on what you like. In these pics, I asked for bones 9 and 10, which is a nice mix of tender and marbled.
Bone in or boneless or tied back
When you ask for prime rib, you might be presented with one of three options: bone-in, boneless, or the bones cut off, but tied back on. Each has its pros and cons:
- Bone in: The most flavor, but also the hardest to handle. Besides the weight, you can only cut slices between the bones. If you don’t intend to use the bones, these will also be more expensive, because while they cost less per pound, you still pay for the bones. Still, by far, they have the most flavor, and isn’t that what’s important?
- Boneless: The easiest to handle, the easiest to cook, but somehow, a little less impressive. Boneless is great if you’re a crust fan (who isn’t?) because you get maximum crust without any pesky bones getting in the way. You’re also able to slice it to any thickness you like. To me though, this option doesn’t really feel like prime rib, just fancy roast beef.
- Bones cut off and tied back on: This one might actually be the most common version you’re likely to run into. This one seems to sells the best, and some internet sources say it’s great for seasoning the meat because you can get under the bone. To me though, it’s the worst of both worlds: you don’t get the extra browning of boneless or the flavor of bone in. I’ve never run into these, but if one magically appeared in my kitchen, I would probably save the bones for beef rib pho and treat the rest as a boneless prime rib.
I’m sure it doesn’t need saying, but I prefer bone-in the most. For me, without bones, it’s not prime rib, it’s just prime.
Where to buy prime rib
Because it’s not a super popular cut and because of how expensive it is, outside of Christmas and Thanksgiving, and maybe Easter, you may have a hard time finding prime rib. The best place to get a prime rib, by far, is your local butcher. Not only will they often have it because they have the whole cow in stock, they will be more willing to cut you exactly as much as you need.
Your other option is a special order from a grocery store’s meat department. I checked with whole foods and they said they were able to get me a prime rib the next day, in the size I wanted. I went with the local butcher, but whole foods was actually cheaper.
You can also get some awesome (and awesomely expensive) prime ribs from online meat purveyors like snake river farms or costco. If you’re lucky, you might find some prime rib locally at costco in its appropriately named prime beef department – just ask.
How to choose the best prime rib
Believe it or not, prime rib was named before the USDA settled on its grades. Depending on who you believe, prime rib is either called prime because it’s the best cut of beef, or because its a primal cut. Either way, prime rib is not always USDA prime.
The difference between a USDA prime and a USDA choice (the second best) prime rib is between 25%-50% more money. Beyond that, if you go to a good butcher, you also have options for organic, dry aged, grass fed, wagyu, and more.
So how do you choose a good prime rib? For me, I don’t worry too much about anything other than marbling. Decent marbling is usually a sign of a happy animal, and that means a good tasting cut of meat. Grass vs corn fed is a matter of opinion, and many people don’t like the extra floral and complex taste of grass fed beef, but I don’t think there’s anyone who doesn’t like tender, well marbled beef.
How to cook prime rib
Here’s how to cook a perfect prime rib, every time:
- Preheat your oven to 450ºF.
- Brown the two sides in a cast iron pan: optional, but highly recommended, especially when you have a smaller roast that’s easier to handle. The smoke detector may possibly go off.
- Brush with butter or oil, then sear in the oven at 450ºF for 15 minutes.
- Set the oven to 200ºF and open the oven door for about 15 minutes, or until the oven temp drops to 200ºF if you have an oven thermometer. The smoke detector may possibly go off, again.
- Cook for 20 mins per pound for medium rare, or until your meat thermometer goes off. Temperatures are below.
- Rest for 30 mins, then slice and enjoy!
How much fat you need to trim away depends on how much you love fat. If you trim all the fat away from the edges, you’ll get a much better sear, but that fat is super flavorful and tender – nothing like the tough chewy fat you might encounter from lesser cuts. My butcher left the fat cap on the spinalis, so I removed and froze that, but left the fat on the iliocostalis for extra flavor.
Do you really need to temper the meat?
Unfortunately, yes, you do really need to temper the meat. Tempering the meat – which is really just a fancy way of saying “leave it out on the counter to come to room temp” – equalizes the temperature of the meat so it cooks evenly, plus it lowers cooking times. You can also use this time to briefly dry-brine the meat (below). For a smaller 2-3 bone roast, you can get away with 2 hours of tempering. For a full rack, you’ll want to temper at least 4 hours.
Dry brining is just liberally seasoning the meat and leaving it in the fridge for 12hrs to 4 days to let the salt penetrate the meat. This process is supposed to pull out the excess moisture from the beef for a more tender and tasty piece of meat. For me, I think this is a waste of time. Salt never penetrates that much in a dry brine. I season the steak during the time it takes to temper the meat and that seems to work for me. But if you have a day or two before you want to cook the beef, it doesn’t hurt. Just lightly sprinkle some salt all around the roast, then place on something to catch the juices. Loosely cover and refrigerate until you are ready to use.
Prime rib temperatures
Prime rib, like all roasts, continues cooking after it leaves the oven while the thermal energy redistributes. For me, this seems to be a 6 degree rise, but your results may vary based on how warm your house is. Basically, 6 degrees is a pretty good estimate, however, so you want to take your roast out 6 degrees before your target temperature. For a quick reference, my target temps are below.
- Rare: 125ºF – remove at 119ºF
- Medium-rare: 130ºF – remove at 124ºF
- Medium: 135ºF – remove at 129ºF
- Medium-well: 140ºF – remove at 134ºF
- Well done: 🤷♂️
The importance of a meat thermometer
A meat thermometer is essential. That old adage about the feel of your ear or touching your thumbs to fingers? Not for important cuts of meat, in my opinion. I recommend an oven probe; one that beeps when the target temp is hit. They can be really cheap, extremely expensive wireless app driven, or something in between. If you have an instant read or thermocouple style, be sure to check often that the roast doesn’t get overcooked.
Because it’s such a large piece of meat, most likely you will not get a lot of flavor into the inside piece. For some people that’s more than fine. The big savory beefy taste is more than enough, especially when paired with some nice flaky sea salt. For others, steak sauces are always welcome. If you’re in that crowd, you should check out our steak sauce roundup.
How to reheat prime rib
You’ll probably likely have some leftover prime rib. You’ll most likely hear that you should reheat the leftovers in a low oven, but I disagree. By far the best way to reheat prime rib leftovers is to cut the remaining pieces into 2” thick steaks (if needed). Liberally season the cut sides, then sear 2 minutes per side in a cast iron pan. It makes for amazing steaks.
Depending on many factors – if your smoke alarm is close to your kitchen, if your oven is less clean, or if your hood fan is a little weaker – you should be prepared for your smoke detector to go off during the browning stages. Be sure to check if your smoke detector has a hush button. Or, have a helpful assistant standing by with a large towel ready to fan when you first drop the roast into the cast iron pan to brown and again when you open the 500ºF oven door.
And that’s it, perfect prime rib, every time. I hope you enjoyed this guide and you’re inspired to make a giant, super satisfying chunk of meaty goodness soon!
Prime Rib Recipe
Everything you ever wanted to know about prime rib: what it is, how to buy the best one, and how to cook a prime rib perfectly, every time.
- 6 lb prime rib 2 ribs, see notes
- 1 tbsp butter melted, unsalted preferred
- 1 tsp kosher salt
- 1 tsp freshly ground pepper
Bones are assumed to weigh 9oz
Prime Rib Recipe
Amount Per Serving
Calories from Fat 447
% Daily Value*
Saturated Fat 19.6g123%
* Percent Daily Values are based on a 2000 calorie diet.