Carryover

[Dave the Cook]

Depsite increasing reservations about the quality of supermarket pork, tonight I roasted a pork loin. I followed a recipe published in this month's Cook's Illustrated. Contrary to most of their pork recipes, brining is not employed. Instead, the roast is browned on the stovetop, then put in a 325 F oven to finish (sear and bung, as we say around here), and pulled at 135 F. According to the recipe, carryover will take it to 150 F, which is good for pork loin, as far as I'm concerned. According to CI, this is the key to keeping the flavor in lean cuts of supermarket pork.

So I have two reservations: quality of the raw ingredients, and now technique. A 2-1/2 pound boneless loin is about 2-1/2 inches across; when it's tied as directed in the recipe, it slims down to about 2 inches. I have serious doubts about 15 degrees of carryover.

I used to have a rule to always follow a new recipe as written -- the first time. I don't stick to this rule as much as I used to. I've gotten to the point where I can tell when a recipe hasn't been tested, or the tester has clearly used equipment that is so different from mine that adjustments will have to be made or it won't stand a chance in Dave's Short-Order Kitchen. But by and large, I trust CI, so I decided to do it their way. If it would make the loin palatable, I was up for it.

I pulled the roast at 135, and with the prescribed 15 minutes for carryover to do its magic, I started to put the final touches everything else. in the middle of mounting the butter for the sauce, I checked the thermometer.

134.

Additional probing confirmed that this was not an erroneous reading. No carryover. Now the temp was 132.

Mrs. Dave comes from a gray meat background. Over 25 years, I've reprogrammed her on many meats, but rare pork is one I skipped over. She might eat it, but there will be lots of questions, and frankly, my answers would lack confidence, because rare pork is, well, rare for me, too. Short version: dinner was late.

I would be willing to chalk this one up to experience, except that this is not the first time it's happened. In my experience, recipes almost always overstate carryover effects, and this is just one example.

So I ask you, is it me, or is it the recipe?

[Wimpy]

Hope someone has the answer Dave. I'm planning a brined pork loin (boneless) for tomorrow's dinner. Would like to avoid a disaster as I am having guests over.

By the way, what kind of stuffing have you had good results with? Am thinking prunes or fig.

[maggiethecat]

We did this recipe too, a couple of nights ago. His Handsomeness was at the controls, and cooking geek that he is, he knows how I feel about pink pork. (But he didn't pull out the Instantread and test the recipe as you did.)

Yuck. Disgusting. Botulism coming my way, and trichinosis. And leprosy . And certain death. But there is a wide area in there that isn't dead grey and isn't too pink. I find that if pork is even slightly marbled you can cook it well. It will be flavorful and juicy.

Did you do the maple glaze? It was good.

Best,

lily

[Matt Seeber]

15 degrees is asking a lot i think. 5 - 10 if your a nice boy and only if you let it carry in the hot pan it was roasted in. by the way, tying the meat sometimes causes it to cook slower if it's tightly compressed. perhaps next time proceed the same but remove the strings while it's resting...

brining tends to draw out some moisture, so for wimpy's recipe i'd say closer to 5 degrees. good luck with your dinner party!

[Mottmott]

Bouland's a la carte site has a wonderful report on carry over:

http://www.hertzmann.com/articles/2002/cook/

[Dave the Cook]

Hope someone has the answer Dave.  I'm planning a brined pork loin (boneless) for tomorrow's dinner.  Would like to avoid a disaster as I am having guests over. 

By the way, what kind of stuffing have you had good results with?  Am thinking prunes or fig.

I like prunes; never done figs, but it has possibilities. I've also done apples and onions -- cutting the sweet without something savory makes a nice complexity, and for prunes I use onion and garlic. Andouille and corn bread is good but a little monochromatic -- pork on pork, just a little sweetness from the corn is welcome relief. Finally, Paul Prudhomme does an oyster stuffing that is quite a surprise. PM me if you want recipes.

I think Matt is right -- five degrees. Of course brining gives you a margin for error, so you'll be fine. The thing is, I didn't get any carryover. I left it in the pan, but the temperature started dropping the minute it came out of the oven. When I saw this happening, I put it back in the heat and left it till it hit 148, then took it out again. This time it carried and peaked at 155. This took about five minutes -- I'm not sure of the exact timing because by then I was resuscitating the rest of the menu.

I'm thinking there's some sort of critical temperature (which must vary according to the shape and density of the meat) you have to get to before you get any carryover. Certainly you get carryover from a standing rib roast at temperatures lower than 135. I read Bouland's stuff a while back; maybe I need to check it again.

Yes, Lily, we did the maple glaze. I took the orange option and echoed it with asparagus and orange-tarragon beurre blanc. You're right, it was very tasty. Eventually. I'll do it again, but I'll brine the pork, or spring for Niman or Pipestone.

Tell HH to be careful with that leprosy -- don't want any essential parts falling off.

[JAZ]

I always thought that much of the carryover was caused by heat from bones (which, I believe, get hotter than the meat itself). So it stands to reason that you wouldn't get nearly as much from boneless cuts. But 15 degrees still seems like a lot to expect. I roasted a whole chicken last week (big sucker, too) and the temp rose by about 8 degrees.

And of course I have no idea where I got the idea about the bones. I thought it was Cookwise, but I couldn't find it in there.

[Dave the Cook]

I always thought that much of the carryover was caused by heat from bones (which, I believe, get hotter than the meat itself). So it stands to reason that you wouldn't get nearly as much from boneless cuts. But 15 degrees still seems like a lot to expect. I roasted a whole chicken last week (big sucker, too) and the temp rose by about 8 degrees.

And of course I have no idea where I got the idea about the bones. I thought it was Cookwise, but I couldn't find it in there.

I think of bones like the old aluminum nail in the baked potato: a way to conduct heat to interior spaces. Being mostly calcium, they are metallic in a way, so they heat up faster than muscle. This is why you avoid them when you position the thermometer. But that means they cool off faster, too, and theoretically, they can draw heat out just as easily as in. But they could also act as internal radiators.

I'm not sure where this gets us. I'm still thinking mass plays a role; your chicken story supports this, I think. How big was it? What temperature did you roast it at?

[JAZ]

I think of bones like the old aluminum nail in the baked potato: a way to conduct heat to interior spaces. Being mostly calcium, they are metallic in a way, so they heat up faster than muscle. This is why you avoid them when you position the thermometer. But that means they cool off faster, too, and theoretically, they can draw heat out just as easily as in. But they could also act as internal radiators.

I'm not sure where this gets us. I'm still thinking mass plays a role; your chicken story supports this, I think. How big was it? What temperature did you roast it at?

Well, I just checked out all my food science books, and the only one who addressed this question (that I could find) was Robert Wolke in What Einstein Told His Cook. And he says that I was wrong. (Damn, I hate that.)

In talking about the reason you don't place the thermometer near the bone, he says "Bone is a lesser conductor of heat than meat is. For one thing, bone is porous, and the air cells are heat insulators. Also, bones are relatively dry, and much of the heat transfer through a roast is due to the water in the meat. So when most of the meat has reached a certain temperature, it's likely that the regions surrounding the bones will still be relatively cool."

So that blows my theory.

But it did start me thinking (or maybe it was the martini). If "much of the heat transfer" is due to the water in the meat, then pork tenderloin, being relatively dry itself, would probably not continue to increase in temp once you took it out of the oven. Does that seem reasonable? You didn't brine this one, correct? So that would mean there was a lot less moisture in the meat than if you had.

When I roasted my chicken, I did a quick soak in brine before roasting. Plus, the chickens I get have a fair amount of fat on them, which keeps the meat even more moist. So maybe my chicken temp rose because of the fat and water in the meat, whereas your pork temp didn't because there wasn't as much moisture.

I'll email a question to Wolke at his web site; maybe we'll get an answer.

Edit: pretty big chicken -- maybe 5 lbs. My oven temp was about 475; I took the chicken out when my thermometer (in the thigh) read 160 and it rose to about 168.

Edited February 7, 2003 by JAZ (log)

[Matt Seeber]

dave - you may be doing this already but regardless...

before roasting or sauteeing any piece of meat i'll remove it from the refrigerator and let it sit at room temperature for a bit. how long depends on the size of the cut. a whole roast for hours, a single steak for 15 minutes. if it's not cold in the center while cooking you'll end up with a more even temperature all the way thru the meat (ie, rare all the way through instead of just in the very center).

[Dave the Cook]

Don't feel bad Janet, Wolke blows my theory, too. You may be on to something with the moisture, though. Pork is cheap these days; maybe I'll do two roasts of the same weight: one dry, one brined, and see what happens, especially as regards carryover. But before I do that, I want to back up to something Matt said earlier:

brining tends to draw out some moisture

What do you mean by that?

There was an article by our very own Russ Parsons in the Atlanta food section yesterday. I found it at the LA Times here (quite amusing to enter in the search engine the phrase "roast parsons," by the way).

It says:

To get to the bottom of this, we took three beef and three pork loins of roughly the same sizes and roasted them -- one each at moderately high heat (450 degrees), one each at moderately low heat (300 degrees) and one each straddling the fence (450 degrees turned down to 300 after 15 minutes).

When the roasts were done, we removed them from the oven and set them aside for 10 to 15 minutes to rest...(t)he internal temperature will increase from 5 to 15 degrees during the rest, depending on the size of the cut (smaller cuts retain less heat).

Two things here. First, the roasting temperature. I used 325, so it was on the low end. And he states explicitly that "smaller cuts retain less heat." What he doesn't say is if he has proof, or if he is employing conventional wisdom. It's intuitive, but we've been tripped up by intuition at least twice already in this investigation.

I am also wondering about Russ' high/low roasting temperature findings as they relate to smaller cuts. In a little roast like a 2-1/2 pound pork loin, how does surface temperature (upon removal from the oven) affect carryover? Maybe Russ will see this and post some additional information.

Matt, thanks for the room temperature reminder, but that's standard practice for me. It's good to get this stuff out, though. Not everybody reading this will know, and it's particularly important to this topic.

[Matt Seeber]

brining tends to draw out some moisture

What do you mean by that?

lay a fish filet on the cutting board and salt it. come back 10 minutes later and it will have sweated.

obviously, dunking pork in a brine overnight will have a different end result but the salt will still have an effect on how the meat cooks. i'm not saying so with a negative connotation either.

[JAZ]

brining tends to draw out some moisture

What do you mean by that?

lay a fish filet on the cutting board and salt it. come back 10 minutes later and it will have sweated.

obviously, dunking pork in a brine overnight will have a different end result but the salt will still have an effect on how the meat cooks. i'm not saying so with a negative connotation either.

But surface salt and brine solutions produce two different results. Brining increases the moisture content of meat.

[g.johnson]

I’m not sure I’m up to explaining physics to people who think that bones are metal because they’re mostly calcium, but I’ll give it a go.

Heat travels from hot things to cooler things. Since the center of the joint is cooler than the surface heat will continue to move from the surface until the temperature equalizes. (Of course, the surface will also lose heat to the air.)

[Matt Seeber]

But surface salt and brine solutions produce two different results

i agree. my original point was that a brined pork loin will cook (not cook up) differently than a unbrined one.

[Dave the Cook]

I’m not sure I’m up to explaining physics to people who think that bones are metal because they’re mostly calcium, but I’ll give it a go.

That's not what I said, Doctor, but I didn't make myself at all clear, so you can have that one.

Heat travels from hot things to cooler things. Since the center of the joint is cooler than the surface heat will continue to move from the surface until the temperature equalizes. (Of course, the surface will also lose heat to the air.)

Thanks for the physics lesson, though learning physics from someone who thinks heat "travels" might be a fool's errand.

Could you explain something less obvious? Does the surface lose more heat to the inside of the meat or to the air? This depends on the relative internal/external temperatures, doesn't it?

[CathyL]

Yes. As I understand it, the rate of heat transfer is driven by the delta in temperature between the hotter item and the cooler one.

[g.johnson]

I’m not sure I’m up to explaining physics to people who think that bones are metal because they’re mostly calcium, but I’ll give it a go.

That's not what I said, Doctor, but I didn't make myself at all clear, so you can have that one.

Heat travels from hot things to cooler things. Since the center of the joint is cooler than the surface heat will continue to move from the surface until the temperature equalizes. (Of course, the surface will also lose heat to the air.)

Thanks for the physics lesson, though learning physics from someone who thinks heat "travels" might be a fool's errand.

Could you explain something less obvious? Does the surface lose more heat to the inside of the meat or to the air? This depends on the relative internal/external temperatures, doesn't it?

Sorry about the calcium crack – I didn’t mean to cause offence. As it happens, though, the distinction between metals and metal compounds is very important when it comes to heat conduction. Metals are efficient heat conductors for the same reason they are good electrical conductors. They have many free electrons bouncing around that can conduct either a current or energy (i.e., heat).

As for you question, I’m not certain. The rate of heat loss depends on both the difference in temperature and the efficiency of heat conduction in the medium through which the heat travels*. Meat is a better conductor of heat than air but the temperature difference between surface and air is greater than between surface and center of the meat.

* A perfectly good usage, I think.

[Dave the Cook]

Sorry about the calcium crack – I didn’t mean to cause offence. As it happens, though, the distinction between metals and metal compounds is very important when it comes to heat conduction. Metals are efficient heat conductors for the same reason they are good electrical conductors. They have many free electrons bouncing around that can conduct either a current or energy (i.e., heat).

As for you question, I’m not certain. The rate of heat loss depends on both the difference in temperature and the efficiency of heat conduction in the medium through which the heat travels*. Meat is a better conductor of heat than air but the temperature difference between surface and air is greater than between surface and center of the meat.

* A perfectly good usage, I think.

No offense taken, G. It'll teach me not to think out loud, in public, after enough wine to make for sloppy thinking, but not enough to keep me from typing. Sorry to have snapped back.

And "travel" is a useful expression, but also something of a pathetic fallacy, no?

As for the question at hand, the answer seems to be, "Well, it's complicated."

[g.johnson]

And "travel" is a useful expression, but also something of a pathetic fallacy, no?

One meaning of travel is simply to move or to pass from one point to another. Coincidentally, the OED cites Rutherford.

1911 E. RUTHERFORD in Encycl. Brit. XXII. 794/1 In an electric field, the positive ions travel to the negative electrode and vice versa.

[Dave the Cook]

And "travel" is a useful expression, but also something of a pathetic fallacy, no?

One meaning of travel is simply to move or to pass from one point to another. Coincidentally, the OED cites Rutherford.

1911 E. RUTHERFORD in Encycl. Brit. XXII. 794/1 In an electric field, the positive ions travel to the negative electrode and vice versa.

Pfft! What's he know?

Uncle.

[Nick]

Thanks for the physics lesson, though learning physics from someone who thinks heat "travels" might be a fool's errand. 

Would you be more comfortable if it were said that heat "migrates"? Really, heat does flow from hotter to cooler. How should we describe it? I've been working with heat for thirty or so years and have usually refered to its transmigration as travels, moves, or flows. Now, that I'm thinking about it, I mostly say that it flows. (As evidenced by my unconscious use of it in my second sentence.)

Edit: Maybe you could get a carry over of 15 degress if you were cooking a whole pig and covered it after it came off the fire.

Edited February 8, 2003 by Nickn (log)

[elyse]

Thanks for the physics lesson, though learning physics from someone who thinks heat "travels" might be a fool's errand. 

Would you be more comfortable if it were said that heat "migrates"? Really, heat does flow from hotter to cooler. How should we describe it? I've been working with heat for thirty or so years and have usually refered to its transmigration as travels, moves, or flows. Now, that I'm thinking about it, I mostly say that it flows. (As evidenced by my unconscious use of it in my second sentence.)

Edit: Maybe you could get a carry over of 15 degress if you were cooking a whole pig and covered it after it came off the fire.

Radiates?

[Suzanne F]

Heat travels from hot things to cooler things. Since the center of the joint is cooler than the surface heat will continue to move from the surface until the temperature equalizes. (Of course, the surface will also lose heat to the air.)

Or, as my MIT-trained husband learned:

"You can't pass heat from a cold to a hotter.

You can try if you want, but you really oughter notter."

Sorry. Carry on.

[tommy]

flux. flow. energy. direction. "travel" seems to work.

great topic. i was just thinking about this the other day and was going to inquire. i, too, was under the impression that the bone had something to do with carry-over. however, i also notice that meat is always less done around the bone. so there went my theory.

carry over can only happen if the meat (or the spot that you've got the thermometer) is in contact with something hotter than it is. that could be a pan i suppose. (a bone, clearly, isn't it). the outside of the meat. so which is it? DTC's theory that the size and shape of the meat affects the carry-over certainly seems reasonable.

i'll check by in 3 days after all of you smart people have fully figured this out. i'd like to see a summary post as well.

Edited February 8, 2003 by tommy (log)