Prime Rib Primer

Prime Rib has such an intim­i­dat­ing rep­u­ta­tion. It actu­ally couldn’t be sim­pler! In response to Nisha, a Secret Life of a Chefs Wife fol­lower, who asked for some point­ers on great prime rib, here is a bro­ken down Prime Rib Primer to boost your con­fi­dence. I can’t think of a more impres­sive meal to serve guests for any din­ner party than one that includes a deli­cious, per­fectly cooked prime rib.

If you are want­ing to pro­duce an excel­lent qual­ity roast for your spe­cial din­ner, you need to under­stand a few things about grades of beef.

The USDA grades of beef include:

1. Prime–This accounts for less than 2% of the beef pro­duced in the US.  The qual­ity is mea­sured by the amount of mar­bling which gives the fla­vor and ten­der­ness, and the age of the ani­mal, which accounts foe the tex­ture of the meat. It’s usu­ally pur­chased by upscale restau­rants and isn’t read­ily avail­able to the aver­age consumer.

2. Choice–This is the sec­ond high­est grade of beef. It will have lees mar­bling than Prime, but if taken from the more desir­able areas of the ani­mal, such as the loin and rib sec­tion, could very closely equal the qual­ity of Prime cuts.

3. Select–This accounts for most of the meat found in the gro­cery stores. It will have much less in the way of mar­bling and will come from older ani­mals. It is not nearly as ten­der as choice or above, and is there­fore much less desir­able as a meat cut.

As you shop for meat, you need to look for the USDA shield accom­pa­ny­ing the label on the meat. It will sig­nify the grade of the meat. Super­mar­kets will include the words “prime” and “choice” on their label to con­fuse you when in real­ity you are really buy­ing a select grade of beef. Unless the words “Prime” and “Choice” are com­bined with the USDA shield, they aren’t actu­ally refer­ring to the grade of beef.

I would assume you could order a USDA Choice piece of meat from the super­mar­ket if you talked to the meat counter man­ager, and I have always been able to find USDA Choice meats at Costco. It runs about $9–11 per pound, where a select cut from the super­mar­ket will be about $6–8. It’s worth the extra price for USDA Choice if you’re going to go to the trou­ble to cook a Prime Rib, which really isn’t all that much trouble.…you just don’t want to adver­tise Prime Rib on your menu and then serve your guests semi-yukky beef!

This is a sec­tion of USDA Choice prime rib. See the beau­ti­ful mar­bling? That equals YUM! Most prime rib roasts run about 13–15 pounds. This one was 15 pounds and wouldn’t fit into my roaster, so I cut it to fit. A 15 pound prime rib will feed about 25 peo­ple with a 1/2 inch cut each. Big­ger “prime-size” cuts will serve about 12.

 I sea­son my prime rib with a rub made from chopped, fresh rose­mary, thyme, gar­lic, and olive oil. There’s also kosher salt and ground black pep­per. It’s about 1/4 cup chopped up rose­mary and thyme com­bined, 10 cloves of gar­lic, 2–3 table­spoons kosher salt, 1 table­spoon black pep­per, and enough olive oil to make a paste when com­bined. Pulse the herbs, gar­lic, and salt and pep­per in a food proces­sor, and then add the oil.

 Instead of using my roast­ing rack, I lay down a bed of aro­mat­ics: car­rots, cel­ery, onions, and the stems left from the rose­mary and thyme. This lifts the roast up off the bot­tom of the roaster, and adds great fla­vor to the drip­pings. You don’t need to peel the carrots.

 Cover the prime rib with the rub, start­ing on the under­side, then plac­ing it on the bed of aro­mat­ics, and then con­tin­u­ing cov­er­ing the remain­ing surface.

If you are strapped for time, you can cook the prime rib for 25 min­utes at 400 degrees F., and then turn­ing down to 225–250 degrees F. for the remain­ing time. If you have the time though, just roast it at 225 degrees F. the entire time. The lower and slower you roast, the juicer and more ten­der the prime rib will end up. It’s worth the extra time.

Tent the prime rib with foil for the first hour and 30 min­utes, uncov­er­ing for the remain­der of the time.

Start check­ing the tem­per­a­ture after 2–2 1/2 hours. You’re look­ing for about 130 degrees in the cen­ter of the roast. You will need a reli­able meat ther­mome­ter to check the temp. I cal­i­brate mine reg­u­larly to make sure it’s behav­ing. The prime rib will rise a few degrees after you remove it from the oven, and 130–135 is a medium-rare tem­per­a­ture. This is the tem­per­a­ture that suits the cut of meat the best. Still very juicy, and red­dish in the cen­ter. An over-cooked prime rib defeats the pur­pose of the extra spe­cial cut of meat.

The ends of the roast will be cooked a lit­tle fur­ther along than the cen­ter, for those guests who insist on a more well-cooked slice.

Let the prime rib rest for 15–20 min­utes to allow the juices to dis­trib­ute through the roast.

Slice and serve with horse­rad­ish sauce and aus jus.


 Here is my prime rib rest­ing. See the beau­ti­ful crust that forms from the rub? Drool-worthy!! This roast will serve about 12–16 peo­ple depend­ing on how thick it’s cut. I like a nice 1″ slice myself!

 Prime Rib is fab­u­lous with a sour cream/horseradish sauce. I usu­ally use 1 part horse­rad­ish to 3 parts sour cream. Some of you might like it stronger, some creamier. Use your own judgement.

The aus jus is made using the drip­pings from the prime rib mixed with a lit­tle water and thick­ened slightly  (not like a gravy, just a lit­tler thicker than broth) with a cornstarch/cold water slurry. You will need to adjust the taste of your aus jus depend­ing on how strong your drip­pings end up being. You might add more water than me, you might need to add a lit­tle beef base to bump up the fla­vor, just be care­ful to watch the salt content.

**As a response to some com­ments from below, I want to add that you may pre­pare your prime rib with the bed of aro­mat­ics and the rub ahead of time to save time. Just be sure to pull the prime rib out of the refrig­er­a­tor at least a half-hour before plac­ing it into the oven to roast. Let­ting it sit at room tem­per­a­ture that long or even a lit­tle bit longer (as much as 1–2 hours) won’t be a food safety hazard. **


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  1. I am try­ing it this week­end. My ques­tion is, does putting on the herbs the night before add any flavour? or no? Do you ser­vice with york­shire pud­dings if so, do you have a killer recipe?

    Many thanks,


    • I would imag­ine it could pen­e­trate the meat some by putting it on the night before, and it’s def­i­nitely a time saver to do that! As for the york­shire pud­dings, that sounds devine! I don’t have a go-to recipe, but would love it if any­one had sug­ges­tions! We could fea­ture it on a future post! Let us know how your prime rib turns out!

  2. Morn­ing Tammy!

    THE Prime rib was amaz­ing. We were not dis­ap­pointed. I had to take the faster route but the meat was so ten­der. It smelled like heaven for the after­noon. Oh and the sourcream/horse radish is the per­fect mate. A true must have accom­pa­ni­ment!
    A friend of mine makes the most cripsy top yet light and ten­der bot­tomed yorkies, and yet again I tried and I failed.

    Ah well, will try again!

    My next recipe of yours will be the creamy cau­li­flower. Look for­ward to it.

    Thanks again,

    Nisha :)

    • Nisha–
      I am so glad your prime rib was a suc­cess! And I agree about the horseradish/sour cream. Just so yum! I am still research­ing the yorkies–can’t wait to give them a try! You should give them another go for sure!

      Have a great day!

  3. I know that the roast must not be cold when it is put into the oven, but I am not sure how long it should be left out before it goes into the oven. It is such a large piece of meat — how long can it be left out and still be safe?

    Your site is lovely. Great photos.

    • It’s true that you shouldn’t be putting the roast into the oven straight from the fridge. The dif­fer­ence in tem­per­a­ture can be a shock to the meat. Let­ting it rest at room temp for an hour or so won’t hurt the meat at all. The tem­per­a­ture dan­ger zone (41 degrees F-140 degrees F.) doesn’t become an issue in that short a time. The fact that you will only be cook­ing the prime rib to an inter­nal temp of 130 F. isn’t a prob­lem either, as the mid­dle of the meat hasn’t been exposed to air, con­t­a­m­i­nants, and poten­tial bacteria.

      Happy roast­ing, and let us know how it turns out for you!

  4. hello! :)
    i am host­ing christ­mas eve din­ner for my fam­ily of 25. i would love to roast TWO rib roasts at one time in one oven, which would allow me to feed 25. is that a good or bad idea? OR do you have another bet­ter sug­ges­tion for a main course?
    thanks so much!

    • Carrie–If your oven can accom­mo­date two roasts, then you are fine! They can be either in sep­a­rate pans, or together in a large roaster, just not with the roasts touch­ing. You should prob­a­bly allow an extra 30 min­utes cook­ing time just to be sure you’re done in time. The roasts will hold over very well for an hour if needed, just sit­ting out of the oven, tented with foil.

      • yay! and THANK YOU! :)

  5. There is only 3 of us and we love prime rib for the Hol­i­days. To serve 3 with left­overs, is a 3 lb road suf­fi­cient? If so, what would you rec­om­mend for reduced cook­ing time?
    And I assume the roast above is bone­less.. correct? :)

    • Angie–Yes, the roast above is bone­less. A roast that size should be just right for three peo­ple. If you plan for about 8 oz. per per­son pre-cooked weight, that will allow for a healthy slice for each of you with decent left-overs. I would prob­a­bly allow about 2 to 3 hours cook­ing time. If it fin­ishes sooner rather than later, you can always pull it out and tent it with foil. It will keep nicely for an hour or more this way. You’ll still be look­ing for the same inter­nal tem­per­a­ture, but I’d start check­ing at about 1 hour just to be safe, just so you have an idea how quickly you are cook­ing. Some­time roasts just take a bit of extra time just to begin to heat up. It depends on the begin­ning tem­per­a­ture of the roast.

      Hope you enjoy!

      • Also on a smaller roast, you should def­i­nitely use the lower roast­ing time, (225 F.). Remem­ber, begin check­ing at 1 hour so you have an idea of how fast it’s com­ing along. Some­times ovens are funny and take longer than you would expect. I’d allow for the extra time to be safe rather than sorry. You don’t want to under cook this roast either. Once it reaches the cor­rect temp, (130–135), It will still hold for up to an hour.

  6. Always cook a prime rib roast with the bone! If you must, you can have the butcher cut the ribs off but have him tie them back on for cook­ing. The fla­vor the bone adds is so worth it! Your rub looks really tasty and I’ll be try­ing that next time. Thanks for the nice site and great pictures!

    • Good point Ken! Bones add bonus fla­vor. Remem­ber that meat nest to bones take a bit longer to cook so allow for this as well.

  7. This recipe looks so yummy. I am going to make it got Thanks­giv­ing. I just need clar­i­fi­ca­tion on how long I cook it for. I will not be rush for time, so how long and what tem­per­a­ture do I cook it for?
    Thanks in advance for your help.

    • If you have the time, you should use the lower roast­ing temp of 225 degrees F. A 12–15 pound roast (aver­age for what is avail­able to most peo­ple), will take roughly 2 1/2 — 3 hours, maybe a bit longer at that temp. It’s nice to allow some extra time, just in case your oven is tem­pera­men­tal. Your fin­ished roast will hold over nicely using the steps listed in com­ments from above.

      Let us know how it turns out! Have a Happy Thanksgiving!

  8. Hi Tammy,

    I have. 7 rib 20 1/2 pound prime rib for 22 peo­ple on Christ­mas Day. How long will I need to cook it to be medium? Should it be cut into two pieces for a shorter cook time? Need your help!!! Thanks, Lorie

    • Hi Lorie!

      You should allow about 4 — 4 1/2 hours to cook, and rest your roast before serv­ing. ***Don’t for­get to allow the time for rest­ing!! This is a cru­cial step!! *** It is pos­si­ble that at 20 pounds your roast will reach the proper inter­nal tem­per­a­ture some­where between the 3 to 3/12 hour mark, but it could also take a lit­tle longer to get to medium. Your roast will have some resid­ual cook­ing after being pulled from the oven and let to rest, and it will hold cov­ered tightly in foil for quite some time, so it is bet­ter to give your­self the ample time for your per­fect temperature.

      You will be look­ing for an inter­nal temp of 135 degrees F. on a meat ther­mome­ter if you want a more medium cen­ter temp. The roast will con­tinue to cook after being removed from the oven to the fin­ished desired temp of 140–145 degrees F. Your end pieces will be closer to medium well, but the cen­ter should be nice and medium. Remem­ber to place the ther­mome­ter in the thick­est part of the cen­ter of the roast. Don’t let the ther­mome­ter be touch­ing fat, or sit­ting close to the bone or it will throw off the accu­racy of your reading.

      Regard­ing the attached rib bones, you can do one of a few things:

      1. Pre-carve the bones away from the roast before cook­ing, fol­low­ing tightly against the bones and then re-forming them to the roast and tying them tightly back on with cot­ton kitchen twine. This will make serv­ing easier.

      2. Roast­ing with the bones, let­ting the meat rest after roast­ing, and then, right before serv­ing, slice the roast away from the bones to make serv­ing easier.

      3. Just cut around the bones as you serve.

      Regard­ing cut­ting your roast in half, it is always prefer­able to keep the roast intact and adjust your cook­ing time to accom­mo­date, roast­ing low and slow for a more even tem­per­a­ture through­out. But it is pos­si­ble to cook the roast in two pieces. I would still go as low and slow as you have the time for, as this is a huge fla­vor and qual­ity contributor.

      So all the above being said I would fol­low this set of steps:

      1. Sea­son your roast sev­eral hours ahead of time or even overnight.

      2. Remem­ber to remove your roast from refrig­er­a­tion a cou­ple of hours before you begin cook­ing to let the chill come off. This will not harm your roast in any way and is totally safe.

      3. Pre­heat your oven to 400 degrees F.

      4. Posi­tion your roast in the mid­dle of the oven. Roast at 400 degrees F. for the first 20 min­utes. This will not do a whole lot to brown the out­side of your roast, but it will help to give your roast a jump start in cooking.

      5. Turn the oven temp down to 225 degrees F. and con­tinue roasting.

      6. Start check­ing for proper inter­nal temp about 2:45 through cook­ing time, if you are going for a whole roast, and about 1:45 if you are going to split roasts in half (which I wouldn’t do unless you absolutely must).

      7. Check every 15 min­utes at first, and then more often as it gets closer. Keep in mind that you will lose heat every time you open the oven which will mean addi­tional cook­ing time.

      8. As men­tioned before, prime rib, espe­cially a roast as large as yours (a big plus in this instance), will hold over a good hour or more if needed. Wrap tightly in foil and keep close to the oven, or even inside on just warm if you aren’t using the oven for cook­ing addi­tional dishes. Ide­ally, you would keep your roast whole, and give your­self a nice, healthy chunk of time for proper cooking.

      Enjoy your meal and your Christ­mas! We’d love to hear how it turned out!

      • Thank you so very much Tammy. I’ll keep it whole as you sug­gested! Will let you know how it turned out after Christ­mas. Thanks again and Merry Christmas!!!

      • So you don’t need to keep open­ing the oven, I use a wire­less meat ther­mome­ter. I’ve used it for Thanks­giv­ing and for roasts on the grill. It’s great to be able to be some­where else and always have a han­dle on what the temp of the meat is. I’ll be using it for my 7-bone roast this Christ­mas. It wasn’t price pro­hib­i­tive, either. I believe it was in the vicin­ity of $29 or $39 at Lowe’s hard­ware. One of the best pur­chases I’ve made so far! Maybe Santa should stop by your house early. :-)

      • Tammy,
        The last of my fam­ily just left and I had to write you ASAP. The prime rib was absolutely FANTASTIC!!!! I can’t thank you enough for your help. Every­one just loved it. We kept it as one roast and cooked it at 225 the entire time, it just about melted in your mouth! This is def­i­nitely a KEEPER!!!!!! Thank you, thank you, thank you!!!!! Hope you ha da fab­u­lous Christ­mas. Lorie

  9. Thanks ken!

  10. Tammy,

    The last of my fam­ily just left and I had to write you ASAP. The prime rib was absolutely FANTASTIC!!!! I can’t thank you enough for your help. Every­one just loved it. We kept it as one roast and cooked it at 225 the entire time, it just about melted in your mouth! This is def­i­nitely a KEEPER!!!!!! Thank you, thank you, thank you!!!!! Hope you ha da fab­u­lous Christ­mas. Lorie

  11. What about 200 degrees instead of 225?

    • Sure! Not exactly sure how much longer it would take to roast but it would work fine if you have the time! Let us know how it works out!

      • The rub was excel­lent. My roast was 14 pounds and took 5.5 hours @ 200 degrees. Meat was soft and very moist. Yummy. The au jus from the drip­pings were a bit salty but every­thing else were perfect!

        • Thanks for your com­ment! I’m glad it was a hit for you! Good to let peo­ple know that a lower temp works out well. As to your salty jus–Did you use kosher salt in your rub? If so, you could for sure cut it back a bit next time you pre­pare a roast. Or stretch out your au jus a tiny bit with low sodium beef broth. If you did use reg­u­lar table salt, that would absolutely make a much saltier jus as table salt amounts would need to be cut almost in half com­pered to kosher. I pre­fer kosher salt for the tex­ture and bet­ter stick­ing ability.

  12. How much oil do I use for the rub?

    • It’s really an ‘Up to you’ answer.….I would sug­gest mix­ing 2–3 table­spoons into the remain­ing rub ingre­di­ents and stir­ring it up. If it feels like it needs a bit more to achieve a paste-like con­sis­tency, by all means add a lit­tle more. You just want to avoid mak­ing it so oily and runny that your rub falls off the roast!

    • I just pour a lit­tle into my palm and rub it all over the rib. So your answer to how much would be as much as you need. :-)

  13. Our fam­ily usu­ally has a nice din­ner on Christ­mas Eve after mass. What would your sug­ges­tions be for prepar­ing this if we would be away for two hours. I am try­ing to change the menu up this year and this recipe sounds fabulous!

    • If your roast is big enough, like the roast in the post, you should be fine to let it roast while you are gone.

      Being there to turn down the temp from 400F, and remov­ing the foil halfway through is not an absolute neces­sity. Just don’t start at 400F, and keep it cov­ered until the last lit­tle bit.

      You could, for instance, mak­ing sure that you let your roast rest all prepped at room temp for an hour, in a pre-heated oven at 200F degrees, (dis­re­gard the 400F quick start time) start your roast 60+ min­utes before you leave, and then, when you get back, take a quick temp and raise your oven to 225F. Depend­ing on the size, it could take another hour+ to come to proper temp.

      If it is a smaller roast, (some do a 5–6 pound roast) I’d pop it in as you leave, still at 200F, and again, upon return­ing, take a temp and adjust the oven temp to fin­ish it off, uncov­er­ing for the last 45 min­utes or so.

      Ref­er­enc­ing the com­ment above from Uncle Calvin, he had a 14 pound roast that took 5.5 hours at 200F degrees that turned out perfectly!

      I usu­ally make a back­wards time­line: I note when I want to serve, esti­mate the cook­ing and rest­ing time and sub­tract back from that to get me in the ball­park. On some­thing like a prime rib, I’d rather have to wait a lit­tle extra time to serve than over­cook such an awe­some cut of meat.

      Good luck and Merry Christ­mas! Let us know if you pro­ceed and how it turned out!

  14. Do you rec­om­mend sear­ing prior to roasting?


    • Tra­di­tion­ally, no. The action of sear­ing arguably should ‘lock in juices’, but I can’t find any evi­dence to sug­gest this is true. If a more deeply browned crust is what you are after, it would be pos­si­ble to omit the high heat at the begin­ning of the time period, slowly cook your prime rib to your desired temp, pull it out to rest and bump up your oven to 450F degrees and after your roast has rested for 15–20 min­utes, and then pop it back in until you get your desired brown­ing on the out­side. Watch it closely though.

  15. What did you do with the veggies?

    • Typ­i­cally they get tossed out because they are con­sid­ered ‘tired’ after being used in this way, but I hap­pen to love pick­ing at the car­rots and onions so most of them get eaten by me! If your fam­ily wouldn’t turn them down, theres no rea­son you couldn’t eat them, although they can be quite salty by this time!

  16. Thanks.My fam­ily like gravy. How would you make it?

    • I either use the drip­pings after the fat has been drained off, if it’s not too salty, or make a gravy from beef stock/broth and beef base. I usu­ally use a roux of fat/flour to thicken, but you can also use a cornstarch/cold water slurry. I hope this helps!

  17. Obvi­ously this roast­ing method would work with a smaller roast but do you think divid­ing the cook time by the num­ber of pounds would be a pretty accu­rate way to judge cook time in this case? My roast is only about 5 lbs but 50 mins doesn’t sound like enough time. (I took your cook time of 2.5hrs and a size of 15lbs to get 10mins per pound.) Even if you cooked your 15 lb roast for another 30 mins that is still only 12 mins per pound. I would be using 225 for the entire time. Any rough guess on what my total cook time would be?

    • Nev­er­mind… I found the com­ment above that talks about smaller roast. I will use this infor­ma­tion along with you beau­ti­ful look­ing rub to hope­fully have a melt in your mouth roast for Valen­tines day sup­per. Thank you so much. Your pic­tures are beautiful!

      • I’m glad you found what you were look­ing for! Weirdly, divid­ing the time used for cook­ing evenly based on poundage doesn’t usu­ally com­pute. I think it must be the time it takes for the roast to even come to a ‘cook­ing’ tem­per­a­ture, and then you have to fig­ure for weight/cooking time beyond that. Thanks for the com­pli­ment on the pics and I hope to hear how your prime rib turns out! Happy Valen­tines day!

  18. Used this recipe 11/15/15. Made enough rub for a 20lb prime rib. Cut back fat cap put, the rub under, then tied rib. Let it set over night before cook­ing. Rib was at room temp prior to putting in oven, cooked total time at 225. Let it rest rec­om­mended time. All I have to say is AWESOME. Guests, LOVED IT. Thanks for post­ing your recipe.

    • You are so wel­come! I love a good primer!! Thanks for giv­ing such a glow­ing review!


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