Cooking For Engineers

[JimW]

I need an engineer to explain exactly how carry over occurs please.

I just cooked a 14.75 lb rib roast at 180F for 6 hours to an internal temp of 120F. I expected very little carry over increase from what I read above here and from other sources. What I got was a 10 degree increase to 130F. The meat was uniformly medium rare inside, perfect, but it seems to me that carry over is much more dependent on the mass of the roast than any gradient of the internal temperature since smaller roasts cooked at high temperatures don't gain 10 degrees outside of the oven, at least in my experience.

[Dilbert]

JimW -

your intuition is spot on - carry over is generated by the BTU stored in "the temperature gradient" - the bigger the diameter, the more mass involved in becoming a gradient, the more absolute BTU 'stored' for carryover.

a larger diameter roast has more mass involved in the outside to inside gradient to store more absolute heat energy - that 'stored' heat energy dissipates to the outside and to the inside. but the outside surface area does not increase linearly to the inside mass as diameter increases.

a larger roast will conduct proportionally more heat from the higher temp mass to the cooler interior than a smaller roast - the balance being lost 'to the outside'

anyway I can confirm your observation that smaller roasts exhibit less carry over cooking than larger ones.

[Zoo Broker]

Just wanted to post my take on this. 17.9lb 7-bone niman ranch standing rib roast ... I used a crust from Tyler Florence... preheated the oven to the max (500F, although my separate oven thermometer read about 465F, wouldn't budge higher). I let the meat come to about 42F, blasted it for 7 minutes, then set the oven to 200F and opened the door until the temperature on the oven thermometer came down to about 275. after I closed the door the temp dropped pretty quickly to 200. I used a probe thermometer and recorded the temp every 15 minutes. After 2 hours, my pretty little excel graph showed me I was going to be almost an hour early, so I dropped the temp to 190. When I was at 118 and now a little behind on the clock, I put it back to 205. For whatever reason, the roast ended up staying at 126 for about 15 minutes before I ticked up to 128. when I took it out, a guest who is a sous chef of a semi-famous restaurant in San Francisco insisted that I let it rest for 30 minutes, which was just enough time to get the oven hot enough for the Yorkshire Pudding as well as heat the prev made gratin. I didn't keep the thermom in the meat as it rested so I'm not sure what the final temp was.

bring roast to 42F time from fridge: 95 minutes
cook at oven temp 465F: 7 minutes
cool oven to 275F: 3 minutes
cook roast to 128F: 6 hours 10 minutes
rest: 30 minutes

result: perfection.

Thanks for the recipe and discussion!

[cordini]

Okay, time for my update......I did the two Ribeye roasts for Christmas Day with a slight variation. My bro-in-law is in the wholesale food industry and when I told him about this method, he gave me "HIS" method of doing Prime Rib, so I fused the two together.....I set the oven probe temp to 138 degrees and set the convection roast feature of my oven to 225 degrees....25 less than what he told me to set it at, but 25 higher than Mr. Chu's method. It all worked out & he couldn't stop "OOO-AAHing" about how well it turned out. I rubbed coarse Sea Salt & course Black pepper into both roasts for seasoning and let them stand @ room temp. for a couple of hours.....Put the roasts in @ 9 am and they were done @ 12:45 pm. They both had a nice brown crust on them w/o searing, and I had a pot of boiling Au 'ju (sp?) on the stove top to finish some of the roast to a "more done" cooking for the kids & others who were not into Med. Rare.....Perfect! The leftovers made great sandwiches later that day.....Thanks for all your help here!

[Rex]

Awesome!
I appreciate a right to the point, quick access and totally understandable solution. This turned out great and I appreciate the post !

Thank you Mr. Chu

Rex

[uzart]

...Cook a roast weighting 1 stone for 45 mins/lbs at 122C .......

No problem! clear as can be!

[becksdrinker]

Followed this recipe for an 8.5 lb rib roast this weekend. I browned it on the BBQ grill to save splattering up the stove before company arrived. It took 3.5 hours to reach 130 degrees. We found that this was at the rare end of medium rare. We placed the slices back in the oven for 10 minutes, watching them the whole while. They did not brown up or dry out but they turned the perfect pink that we were looking for. The roast had nice marbling to begin with and this method kept it moist and very tender. The best part was there was only a thin coat of browned roast, maybe 1/8 inch and the rest was evenly cooked to the desired degree of doneness....Not just done in the center.

[Terri Moran]

Hi, I've eaten a lot of good prime rib in my days. I have eaten it all over the country and about half of the world. Believe me, in the corporate world, you get to eat a lot of Prime Rib. I just thought that I would pass onto your readers, that the Best Prime Rib that I have ever eaten, in my entire life was at a place in the Carolinas, near Asheville, The name of the place was "Kutchie's Key West Cafe'," That prime rib would melt in your mouth. It was also the most flavorful prime rib that I have ever tasted. I could cut it with my fork. And that's no bull.
The very nice "Babe" that was serving our table, told us that the owner "Kutchie Pelaez" only uses "certified black angus western prime beef", not just for his prime rib, but for his steaks. That he even grinds it for his world famous cheese burgers, called the "goody goody, the cheese burger in paradise." I might try one of those the next time we are in Carolina but I don't think-so. That prime rib would be very hard to beet. That young lady told us that Mr. Pelaez was a beef expert and that he age all his beef on premises n his own storage facilities. I told her I was very impressed and the proof was in the pudding and that was the finest prime rib that I have ever eaten. A great baked potato, a fresh garden salad. Top all that off with "The Best Key Lime Pie in the World" and you've just eaten better that a 10-star dinner. Oh and the Island Drinks that this place servers are second to none, they will knock you on your ass if you are not careful, no watered down drinks at Kutchie's Place. Just the Best Damn Food and Drinks you can get anywhere in the world.

.....Terri Moran,....Los Vegas

[tghodge]

I've wanted to cook a large roast for a long time. I originally thought that the 45 minute/lb would work...but after much reading, I figured out that the time would be anywhere between 5 and 6 hours.

I don't like the high heat/slow cook method, so I went with a straight up 210 degree (F) oven for the hole time.

I let the roast stand overnight in it's cryo-pack and when I put it in the oven, it was at an internal temp of 69 degree F. I started the roast at 12:30 pm at 210 degree F. The roast was at 131 degrees at 4:45 pm. I turned the oven down to 170 degrees to slow it down, and ended up turning it off around 5:30 when the internal temp was around 135. It went up to 136 in the oven that was turned off over the next 20-30 minutes.

I pulled it out and started carving a around 6:00 pm....to VERY awesom results. The whole rost was perfectly medium rare. The very center was medium rare to rare....

It was the first time I had cooked a whole rib roast...and I would do it the same in a heart beat.

I think the biggest difference in cook time is made by how much time it is allowed to come to room temp. If you take it out of the fridge at 45 degrees, it will take closer to 6 hours. If you let is sit overnight as I did - I think the target time is much closer to five hours.

BTW - this is the BEST page for information and discussion about baking, broiling, smoking, and just plain cooking a rib roast (prime rib) that I hav EVER come across.

Thank YOU!

Travis.

[Lesley]

I'm not an engineer but I'm always game to try new and interesting methods.

My roast is dry ageing as I type this, at the end of day 2. I'm giving it another 24 hours. The only variation is that I wrapped it loosely in cheesecloth as per the instructions on another site. It still smells good - the wrap gets changed daily. I'm going to sear it on the BBQ to save the splatter on my stove-top and then roast it as per your instructions.

To all those people who complained about the units used, quit being so silly. Use a calculator if you can't convert the numbers in your head.

[omni1]

Every Christmas dinner for the family (in Laws) for years - warm cracked peppercorns in pan, when fragrent mix in some kosher salt and rub roast and let stand to bring to room temperature. When ready put in 210 degree oven w/probe set to alert at 113 degrees. When alarm goes off, I remove roast and cover w/ foil. I bring oven up to 450 degrees and when ready I reset probe alarm to 122 and put roast back in then promptly remove when alarm goes off. It puts that wonderful carmalized crust on roast but accomplishes the goal of medium rare all the way thru center to edge as I let it rest and in about 18-21 minutes it always comes up to 130 and then I slice and serve!! AWESOME!

[timcow]

quick reminder , check your cooking appliance for the working tempreture. Calibrate accordingly. happy holidays

[Guest]

I plan on using a 200F oven to cook a 10lb PRR to the desired 115F (we all like it rare) then turning up the oven to 500F (letting the meat rest) and then putting it back in the oven to create the crust.

One question though-
When I take the meat out the first time once it reaches 115F, many say to wrap it in foil, let it rest for 30 minutes, then return it to the 500F oven for about 10 minutes. Do I return it to the oven with the foil on or off?
Seems like it wouldn't crust well with the foil left on, but I never see instructions that say to remove the foil.

[Dilbert]

cover / foil _off_

your instinct is absolutely correct - creating a crust under foil is not going to happen....

[sammysalsa]

After the meal has taken place, I like to cut the leftover prime rib into steaks and vacuum pack them in individual servings and put in freezer.
When the need for a good meal hits you, you take one of them out and let it thaw, heat up a package of ajus mix and put the steak inside the ajus to heat it up. It comes out tender and moist just like when you made it and didn't take much time.