Cooking time for 2 prime ribs

[atty]

I sincerely try to diligently search before asking the stupid question, but I have not been able to find any posts that directly answer my question, although several have mentioned it.

I have been commissioned to do the honors to 2 10lb prime ribs and use a recipe that calls for approx. 5 min/lb in a 500 deg. oven., then turn oven off and allow to cool, etc. Since I'm handling $160 worth of beef, my sense of adventure is a little on the slim side. Does anyone have any thoughts as to how much of a variation in total cooking time will occur with 2 roasts instead of 1?
Common sense tells me that it is going to take longer, but I'm not sure that two roasts sufficiently spaced from each other is going to make a significant difference. Any help would be appreciated.

 

[Andy M.]

Without commenting on you cooking method, I'd say the cooking time wouldn't be much different. Wouldn't your method work with one 20 pound roast?

Your best bet is to use a meat thermometer to ensure proper cooking.

I've used a similar method with different times.

 

[auntdot]

Gosh atty you have brought up an issue that has confused me for years.

And that is heating times for several pieces of meat.

Has always seemed to me that the heating time should depend upon the surface area of the meat, and two ten pound roasts should have more surface area than one 20 pounder. And so, they should take less time to cook than the bigger one. (To reduce the logic of that principle to the absurd imagine cutting the stuff into little strips, they would take almost no time to cook.)

Would probably treat it as one 10# roast, although in my experience two take longer. I am not exactly sure why and like I said this whole thing confuses me.

And would rely on the thermometers, both the one that measures the oven temp and the one you put in the meat.

Always like meat on the rare side, make that raw side, so am very sensitive about cooking times and temps.

As Andy said, use the gadget.

 

[atty]

Thanks for the comments. Andy, my first thought is, in fact, to treat it as one 20 lb. roast, but then I'm not sure the cross section area would be the same. Certainly Auntdot's analysis has merit when you talk about increasing the surface area exposed to the heat. Then again, maybe we're only talking about the initial "heat" load to the oven. Obviously a 10 lb. roast at room temp. appears to a 500 deg. oven as a large "ice cube". Put in two ice cubes, and the temp is going to drop even further. If it's a large oven, then I suspect the significance of all this becomes less. Still the effect of the 2nd roast is there.....I just don't know whether it warrants a change in total cook time.

Thanks again for your thoughts. I agree the safest is the meat thermom. I was just trying to avoid opening the door for checks.

 

[Andy M.]

Your method is non-standard. That's why I made the comment I did. My comment was to say, if you can do a 20 pound roast, you should be able to do 2-10 pound roasts. If there is plenty of room in the oven so air can circulate, you should be OK. Where you are using residual heat to cook the meat, It may take a little longer as you have twice as much cold meat that needs to be heated to a specific temperature.

I use a meat thermometer that has a remote probe. You put a probe into the meat and it's connected by a wire to a display on the counter top. No need to open the oven.

BTW, my version of the method you mentioned is: roast goes into a 500F oven and cooks for 12-14 minutes per rib (12 min. for rare; 13 for med. rare; etc.). Then you shut off the oven and walk away for at least an hour and a half and it's done. Using this method, you cannot open the door at all.

 

[Hopz]

I think the answer is to invest in the probe thermometer.

Gosh- $140 worth of meat vs a $20 thermometer... let me think about it for a minute...

The thermometer will become one of your most used kitchen devices. It will improve just about anything you roast or grill. I just got a remote one... it has a probe with a transmitter, and a receiver unit. I can sit with my company with the receiver and know how my cooking is going... love it.

 

[Michelemarie]

Atty, wish I was at your house, I haven't had prime rib in ages and I wanted that for Christmas dinner but was outvoted. I agree - probe meat thermometer - I love mine - although where the heck are they $20? MIne was quite a bit more, but I'm not complaining, I love it! Good luck with the meat!

 

[JDP]

I writing this assuming you have a standard size household oven. Two 10# roasts will take longer than but the amount of time I'm not sure. The 500 degree for 15 minutes does work but it will increase you shrinkage. I recently saw a show on Good Eats and he took his rib roast and started it at around 250 degress, coooked it to temp ( depending on you prefered level of doneness) Took the meat out and let it set and then finished it in a hot oven to crisp it. This goes along with the resturants coof primes in an Alto Sham oven at lower temps giving a very tender and juicy outcome while reducing loss. I have attached a link to that recipe.

I aslo completely agree with the digital themometers for me they are indispensible in roasting and smoking meats.

Recipes : Dry Aged Standing Rib Roast with Sage Jus : Food Network


Good Luck and Merry Christmas,

JDP

 

[Alix]

And my method is different yet. The meat goes into an oven preheated to 500 for about 15 minutes, then I turn it down to 325 for 15 minutes/lb and it is always a perfect medium rare.

I also don't know that two 10lb roasts would cook much differently than one 20lb roast. Sorry not to be helpful there. My vote is with the meat thermometer too. Make sure you get a good one.

 

[Candocook]

I do roasts similar to Alix and Andy and definitely rely on my instant read thermometer for when to take it out. The thermometer should also be inserted into the roast horizontally, not vertically.
I think (as Andy) that if there is room for air to circulate, it will not be a significant amount of difference in cooking two at the same time. Do let them be at room temp.
I also start at 500* and think shrinkage is a non-issue. The nice brown coating counts for a lot!! But the long slow method is fine--IF you have a large enough piece of meat.

 

[Nicholas Mosher]

It's done when the thermometer you have says it's done!

I preheat to 250ºF, stick the roast in and immediately turn it down to 200ºF. Slowly roast until a thermometer inserted into the thickest portion of the meat registers 130ºF, then pull the roast. Rest it beneath some tented foil and increase the oven temp to 500ºF. Put the roast back into the box and roast for 10-15min, just enough to render the exterior fat and brown the muscular tissue.

Rest another 15-20min, then carve n' serve! You want to cook with as gentle a heat as possible which will keep those ugly bands of well-done/gray meat from polluting the outer layers of the roast. The above method will yield a medium/medium-rare doneness from the center of the roast almost all the way to the exterior.

Just my two cents of course.

 

[atty]

A great big thanks to all for your input. It appears the common denominator in all responses is the need for a remote ther. and staring at my three conventional ones on the weekend before Christmas with five hours to go before serving time, is not going to earn me very many points for planning. The only thing I can do at this point is to take a calculated shot at some "blended" amount of time between 1 and 2 roasts and hope to err on the rare side. I promise to keep a stiff journalistic upper lip and report the results, success or disaster.

 

[YT2095]

I understand your "ice cube" analogy, however it doesn`t Quite work like that, the Initial load will require more energy sure (you oven stays ON for longer) but that`s the internal thermostat, it`s acutaly compensated for.
what you have is latent heat LAG, it won`t take twice as long to melt 2 cubes as one as it`s not what`s called a "Closed system" you`de be looking a 1/3`rd extra time max depending on volume.
Now then, Surface area is fascinating in that it does Plenty to compensate for this over time
(it`s even classes a reaction accelerant), put them in according to instructions and give them 1/3 extra time (it`s not linear like you`de expect).
and certainly use the thermometer!

hehehe I`m somewhat envious that you have Beef ribs there too, I can`t get them here for love nor money.

 

[atty]

Interesting. At least you're willing to commit to an extra amount of time and quantify it. I certainly agree with your initial load approach. Then if we have a recipe that calls for 500F for one hour, then turn oven off and sit for two hours, would you surmise that it would be reasonable to increase the 500F time, but leave the 2 hour time the same...on the theory that the additional "ice cube" would be absorbed in the first heating phase?

 

[Corinne]

I did Prime Rib (boneless) for the local homeless shelter for Christmas last year & I'm doing it again this year. Here are my notes from last year for cooking it:

BEEF - Let sit outside at room temp. for 1 hour. Preheat oven to 475º.
Bake for 30 minutes. Reduce heat to 325º. Continue roasting until internal temp. reaches between 130º - 145º. Meat will continue to cook when removed from oven. Let sit for 15 minutes before carving.

I did a lot of research because I was cooking such a large quantity of expensive meat for someone else. I'm doing 34 lbs this year. It's 34 lbs divided between 2 roasts. Last year, after talking to the butcher, I cut the roasts into smaller pieces & I will do the same again this year. I remember going to the shelter the evening before to cut the roasts & rub them with an oil/seasoning mixture, stuck some garlic into slits & refrigerated it overnight.

I don't know if this helps you or not - I sure hope so! Best of luck!

 

[leewag]

The recipe I use calls for starting the roast(s) at 450 for 25 minutes and then turning the oven down to 350 for 16 minutes per pound until the internal temperature reaches 135-140 for medium rare. The meat thermometer is, as you see, an essential instrument here. Doing the garlic slits thing is another tasty thing to do. Good luck. Seems a lot of folks are doing rib roasts this year.

 

[Candocook]

A great big thanks to all for your input. It appears the common denominator in all responses is the need for a remote ther. and staring at my three conventional ones on the weekend before Christmas with five hours to go before serving time, is not going to earn me very many points for planning.


It does NOT need to be a remote thermometer. You can get instant read thermometers for $5, if you had time to shop. They can be easily had in the supermarket aisle for $14 or so.

 

[atty]

Well Folks, here's the autopsy report. Viewer discretion is advised. As long as we're listing all the reasons why this train derailed killing all aboard, let me start off by saying that my oven is a DCS, and for those of you that are not stateside, it is a home version of a commercial oven....that is to say it is no slouch.

The recipe was 5 min/lb at 500F, then two hours at oven off. My "blended" time for two roasts was 4 min/lb at 500F, then the same two hours for oven off. The result was a disastrous 155F on one and 145F on the other. Suffice it to say that my crematorium had no trouble with 2 roasts, and I suspect it would not have blinked at 5. So if anyone had any questions about the number of roasts vs. cooking time, I'd have to say fahgedda 'bout it!! Obviously this venture will not happen again without a remote therm., but I have to wonder how they did it in the old days without such a wonderful technology. For a first timer, it would have to be a lot of luck.

Thanks again for the thoughts. I'm off to resole a few pairs of old shoes with 20 lbs of prime rib.

 

[Nicholas Mosher]

Yeah, go much over 140º (on the finsihed side) and you're talking gray football. Roasting quickly at high temps also produces bands of overcooked gray meat around a juicy red/pink center. Low and slow is the way to go (along with a thermometer of course)!

Sorry to hear about your expensive experiment gone south...
Make a solid beef gravy and serve the slices of roast covered in that over some mashed taters.

 

[YT2095]

erm, perhaps I should have made it a little more clear instead of assuming you`de know this, but the same effect I mentioned on the Heating side also effects the Cooling side too, with that Mass of product in there at the correct temp, it would also take longer to cool too (latent heat energy).

consider this though: "there`s no such thing as a failed Experiment, Only more Data"