Cooking time on a 21 pound rib roast???????

Depends on the temperature and technique. I know that when I did one at 400F for one hour and 275F until done, it got to medium rare in 8 hours. It is a large cut of meat. I assume bone-in here.

well well well, how you cooking it, i know for a fact, cranking it up, 500 degrees or so, about 5 mins a lb, than drop to 225 until internal of 135 yields a mighty nice perfectly medium rare roast, but thats just how i like mine. And it'll only take u 2-5 hrs

umyaya said:

I did a trial run not too long ago with a prime rib roast that had only 3 ribs (~7 pounds). I'm smoking a 21 pound rib roast for a party tomorrow night (7 ribs). I can find posts that say 10 hours and posts that say 5 hours. Any help would be greatly appreciated!

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umyaya said:

Sorry, my plan is to cook it at 250 the whole way.

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I agree about the 250* pit temp. But here is something to consider..... Of the 20 or so folks at this party it might be possible that more than two want an end cut. Cutting it in half or thirds will increase the end cuts.

My worst habit is not paying attention to the actual cook times. I generally have an hour window for any sit down time, and I never worry if I don't hit that. That said I put a request at the top of my standing rib roast page on my cookin' site asking for cooking times. Of the 20 or 25 responses here are the results.

Standing Rib Roast - Cook Times

4 pound roast - 220° -250° pit temp - 2 hours to reach 125°
7 pound roast - 250° pit temp - 3 hours 40 minutes to reach 123°
7 pound roast - 220° -250° pit temp - 3-1/2 hours to reach 125°
10 pound roast - 220°-228° pit temp - 3 hours to reach 120°
14 pound roast - 220° -250° pit temp - 4-1/2 hours to reach 125°
15 pound roast - 220°-250° pit temp - 4 hrs 50 min to reach 127°

I hope you have a cable thermometer, they are really handy on roasts like this. When the internal gets close to 100*, you can decide if you need to alter the pit temp to coincide with your sit down time.

Cooking Prime Rib

We do a lot of prime rib at the joint during the holidays. Most of them run close to 20lbs. I smoke them around the 250 degree range. Why? Two reasons...since this cut of meat is pulled off the smoker at a much lower temperature than a tough cut of meat (brisket, ect.), it won't be on the smoker nearly as long. At around 250 degrees, it will cook long enough to develope a good smoke penetration. Second reason is that this temperature is hot enough to create a nice bark for the amount of time the prime rib will be on the pit, if you don't pull it before around 140 degrees internally. Most of my customers want it cook to around 140-145 internally. If I pull them at 140 degrees internally, they will generally rise to about 144 degrees before the internally temperature starts to drop.

Remember an important tip when trying to cook for a crowd. People that like their beef rare will eat it if it is a little past that point (not burned up!). However, people that like their beef done will not eat rare beef (most of the time). Just something I've pick up over the years.

Danny

Time Factor

Sorry, forgot to give the time. It usually takes about 6 hours for a 20lb. rib roast to reach 140 degrees internally cooked at around 250 degrees pit temperature. Different pits cook different. This is the general time factor on my pit (Oyler 700). Plus I normally have a big load.

Danny

Danny said:

Remember an important tip when trying to cook for a crowd. People that like their beef rare will eat it if it is a little past that point (not burned up!). However, people that like their beef done will not eat rare beef (most of the time). Just something I've pick up over the years.

Danny

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I believe that is absolutely true. I have found that folks that want it cooked to past medium (no pink) will not eat anything short of that.

thirdeye said:

I agree about the 250* pit temp. But here is something to consider..... Of the 20 or so folks at this party it might be possible that more than two want an end cut. Cutting it in half or thirds will increase the end cuts.

My worst habit is not paying attention to the actual cook times. I generally have an hour window for any sit down time, and I never worry if I don't hit that. That said I put a request at the top of my standing rib roast page on my cookin' site asking for cooking times. Of the 20 or 25 responses here are the results.

Standing Rib Roast - Cook Times

4 pound roast - 220° -250° pit temp - 2 hours to reach 125°
7 pound roast - 250° pit temp - 3 hours 40 minutes to reach 123°
7 pound roast - 220° -250° pit temp - 3-1/2 hours to reach 125°
10 pound roast - 220°-228° pit temp - 3 hours to reach 120°
14 pound roast - 220° -250° pit temp - 4-1/2 hours to reach 125°
15 pound roast - 220°-250° pit temp - 4 hrs 50 min to reach 127°

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When I grow up I want to be as smart as thirdeye :icon_blush:
I have smoked a whole Rib roast up 115 then seared the outside on
a wicked hot grill.

Danny said:

We do a lot of prime rib at the joint during the holidays. Most of them run close to 20lbs. I smoke them around the 250 degree range. Why? Two reasons...since this cut of meat is pulled off the smoker at a much lower temperature than a tough cut of meat (brisket, ect.), it won't be on the smoker nearly as long. At around 250 degrees, it will cook long enough to develope a good smoke penetration. Second reason is that this temperature is hot enough to create a nice bark for the amount of time the prime rib will be on the pit, if you don't pull it before around 140 degrees internally. Most of my customers want it cook to around 140-145 internally. If I pull them at 140 degrees internally, they will generally rise to about 144 degrees before the internally temperature starts to drop.

Remember an important tip when trying to cook for a crowd. People that like their beef rare will eat it if it is a little past that point (not burned up!). However, people that like their beef done will not eat rare beef (most of the time). Just something I've pick up over the years.

Danny

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Danny said:

Sorry, forgot to give the time. It usually takes about 6 hours for a 20lb. rib roast to reach 140 degrees internally cooked at around 250 degrees pit temperature. Different pits cook different. This is the general time factor on my pit (Oyler 700). Plus I normally have a big load.

Danny

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Aw man, are you Danny Gaulden? If so, I'm glad you are posting here. If you are.....You are personally responsible for some of my big steps in barbecue.

Hello Thirdeye,
Yes, this is Danny G. So glad I helped you become a better bbq'er. Thanks for the kind words. You just made my day. This is quite a forum, just couldn't resist joining.

Danny

Danny said:

Hello Thirdeye,
Yes, this is Danny G. So glad I helped you become a better bbq'er. Thanks for the kind words. You just made my day. This is quite a forum, just couldn't resist joining.

Danny

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You're welcome....You are responsible for getting me hooked up with Rocky and my BDS's. I just sent you a Private Message