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The case of the cooling brisket – Hypothesis 1

edited November -1 in EggHead Forum
The case of the cooling brisket – Hypothesis 1

I’ve had time to think about the brisket ‘debate’ we had the other day. I have good news and bad news. The good news is (from others perspective): I admit I was wrong. The bad news is (again, from theirs): their explanation of the mechanisms to explain a temperature drop in a brisket during a long cook was also wrong.

So the way I understood the problem was DC egger has a brisket that had hit a plateau and then dropped in temperature. I pointed out that something in an environment hotter than itself cannot cool down. For this to happen, you actually need energy to flow from a colder body to a hotter body this is impossible and against the laws of thermodynamics. Anyway, others said it could happen, accusations of trolling, personal insults overtook the thread, my wife gave birth, the brisket was ruined and apparently WessB threatened to murder someone (although I missed that). Anyway, here is my explanation for why this ‘drop’ in brisket temperature, that is consistent with the laws of thermodynamics and explains the observed drops in temperature that are occasionally observed (but not always) when cooking large fatty pieces of meat such as pork butts and briskets. Judge it as you will, but please lets keep this civil and an interesting debate.

We all agree that a temperature plateau occurs when cooking large pieces of fatty meat. Much like the rising sun, this happens during every low and slow. Most of these cooks (mine at least so far) show a rapid increase in temperature, a plateau and then a slight higher rate of increase at the end – with no drop in temperature in the meat being observed. Here is an example I found:

ramp_mode_05.jpg

That is not always the case, however, apparently here, a small drop in temperature was observed in the plateau phase (although maybe it was due to the opening of the dome but I doubt it would have that much effect).

Stoker01.jpg

So now we are left with this: a plateau always occurs, but sometimes the temperature probe shows what seems to be a drop in temperature of the meat, when we know that something cannot get cooler when it is present in a hotter environment.

The reasons, I believe are this:

First, a temperature probe is not measuring the temperature of the meat as a whole but actually a very small location in the meat and we generally take it to be representative of the whole (not always, for example when cooking steaks, we pull when our probe is reading below our desired finish temperature because we know the outside of the meat is much hotter than the internal). The point here is that the probe is not measuring the temperature of the whole piece of meat.

Second, large pieces of fatty meats such as briskets and butts are very heterogeneous and as such some parts will have a higher fat content than others. Portions of the meat which are low in fat will show a relative linear increases in temp (hence no real plateau in lean meats), while other section of the meat that are fattier will hit a plateau at the rendering temperature of ~155oF. The point here is that different section of the meat heat at different rates.

Lastly, heated liquids like to move. Tangent: My hydraulic furnace broke so the one way valve in it was constantly open and heated would slowly migrate throughout the system even with no pump. Annoying. Anyway, the point is that fluids move around when they are heated.

Thinking this through I think the only a logical explanation for occasionally observing a drop in temperature in the brisket is you have your probe in a relatively lean portion of the brisket, it heats at a faster rate compared to the fattier portions, and then pork fat which requires additional energy to change state ~155 migrates to this area showing a small drop in temperature at the site of the probe (nature abhors a vacuum eh?)

This post has dragged on longer than I had planned so I will wrap it up.

To summarize:
1) Heat cannot move from colder object to hotter objects.
2) Briskets and pork shoulders are heterogeneous and fatty parts require additional energy to change from a solid to a liquid around 155F, hence the existence of the plateau effect.
3) Lean portion of the meat require less energy to reach higher temperature because the water plateau doesn’t occur until 212F
4) Hot liquids can move around cuts of meat

I find this explanation satisfying because it also explains the ‘turbo butts’ we occasionally hear about (although that may be due to a poorly calibrated thermometer as well). Lower fat content –> less energy required to heat to 195F

All in all it turns out I was right in the case of obeying the laws of thermodynamics (it’s easy to stand on the shoulder’s of giants after all) – although I was wrong to attribute it to temperature variance of thermometer readings. Then again, other were also wrong with their explanations of the mechanism to explain what they observed and why thermodynamics didn’t apply to briskets.

Anyway, this was just a logic experiment but I think it holds water (or rendered fat at least). ☺

Makes sense to me at least. What do you folk think? Please keep it civuuul!
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Comments

  • ChuckChuck Posts: 812
    Since you asked I think you should have just let the whole brisket thing die. I won't comment on your "hypothesis", also know as an educated "guess".
  • hornhonkhornhonk Posts: 3,832
    Shaddup shutting up! Jeez... :woohoo:

    foghorn3.jpg
  • Big KnifeBig Knife Posts: 35
    I see you're ignoring the possibility that the hydrolysis of collagen to gelatin is an endothermic reaction.

    You really think migrating molten fat will cause a DROP in temperature?
  • Sorry, not at all. The endothermic reaction is the cause of the plateau. It just doesn't 'pull' heat from other parts. Same as when you boil water - it boils at 212, it doesn't drop to 205 while the change in state is occurring.

    Sorry that wasn't clear, I didn't mean to ignore you point before.
  • BasscatBasscat Posts: 626
    OMG. Get over it! Cook the damn brisket until it is done. Then rest it, if you want, then eat it! Don't you have a wife and new baby you should be looking after or fawning over? Enjoy the great blessings you have, don't wast time over stupid stuff like "brisket science"! Please. Seriously, life is too short to fuss over such nonsense.
  • hornhonkhornhonk Posts: 3,832
    Hooray for Basscat! Thank you.
  • Big KnifeBig Knife Posts: 35
    Tweev-tip wrote:
    Sorry, not at all. The endothermic reaction is the cause of the plateau. It just doesn't 'pull' heat from other parts. Same as when you boil water - it boils at 212, it doesn't drop to 205 while the change in state is occurring.

    Sorry that wasn't clear, I didn't mean to ignore you point before.
    That's a different process though. To my mind you have two processes occurring; a) the melting of fats and b) the breakdown of collagen. One is a transitional (physical) change requiring energy (causing the plateau similar to your water example) and the other is a chemical reaction which (possibly) removes energy (heat) from the system.
  • I was just thinking about that during my drive home. At least the part about how I was implying that physical (which are reversible) reaction with a chemical reaction that are not (you can't unfry an egg).

    I don't really see how the rendering of fats could be considered an endothermic reaction though... To me it's a heat based chemical reaction akin to frying an egg that results in a permanent change in composition. Could you provide a similar and comparable process?

    What part about my logic flow didn't hold water for you? I thought it seemed quite reasonable.

    Thanks for being civil.
  • holy guacamole, it's like a turd that just won't stop stinking. even a douchebag knows that sometimes people can experience things without being able to explain why it happened. you're the fool that stood your ground and told them that what they collectively had experienced many times was impossible. i suppose your next target is that chick that saw the virgin mary in her grilled cheese sandwich. you can convince her that was impossible too since she can't explain it scientifically.

    sandwich.jpg
  • BasscatBasscat Posts: 626
    Just cook it 'til it's done, eat it, and don't worry about it. It may be done earlier that you planned, may be done later, but it will still be good, and the world won't change if dinner is late, or early. I don't really care, but have you thought about why this is so important to you? Geez.
  • Thanks for keeping it civil. It's not that important to me I just have always liked thermodynamics because of it's simplicity and how it provides order (which is somewhat ironic because it's about disorder) to things.

    I don't see why people are so offended by the post. I think it was at least marginally insightful. We all know there are myths in cooking (eg beer can chicken, smoke rings etc) so aren't we all better off understanding the finer details of things?? All I did was disagree with the process of why a brisket would drop on temperature because the reason given was impossible. I was yelled at because I didn't immediatey defer to someone with more posts than me. Sorry to tell you but if you have lots of posts I will seriously consider your thoughts and ideas but I won't simply accept them as gospel if ideas and conclusions cannot be supported.

    Anyway over 500 have read this thread. Hopefully those people have learned something and the "magic brisket" can go the way of the beer can chicken.

    If you cannot contribute positively to the discussion please find another thread. Than you.
  • BasscatBasscat Posts: 626
    It's not thermodynamics, dude, it's cooking a brisket. It's done when it's done. If you don't think that's a positive contribution to the discussion, you don't cook much, or don't enjoy the adventure that is cooking. Please enjoy your family instead of wasting time on the Forum.
  • Dear Tweev-tip,

    This is my first post.

    Thank you for your hypothesis, I quite enjoyed that. I love a healthy INTELLIGENT discussion, as that is how we learn. (if we want to) I also liked the graphs, what equipment did you use to collect the data?

    I am currently thinking about the impact of moisture loss in relation to temperature of the brisket and the surroundings ... (will sleep on this)

    Reading this post has made me hungry for brisket; if I wasn't doing lamb this weekend - it would be brisket time!

    Cheers,


    p.s. thermodynamics was not one of my favorite classes, yet the principles can be applied to many everyday occurrences.
  • bitbucketbitbucket Posts: 4
    How can you tell how many have read a given post? That would be interesting to see.
  • FidelFidel Posts: 10,168
    All I did was disagree with the process of why a brisket would drop on temperature because the reason given was impossible

    That is just a flat out lie. This is why people don't like or appreciate your contributions here. You twist the truth to fit your agenda and make it appear, after the dust settles, that you were the victim all along. This isn't about you not deferring to people with a high post count. This is about you stating that the experiences people have posted here time and again were false. Basically you called us all liars because we couldn't tell you why.

    You didn't disagree with someone with more posts than you. You disagreed with a whole host of people (me included) that have cooked exponentially more briskets than you. We told you what we have witnessed and you stated over and over again that we were wrong and what we have witnessed was impossible.

    Just because we don't explain something to your level of understanding doesn't mean it doesn't happen, and certainly doesn't make it impossible. I can't tell you with any acceptable level of precision how an airplane flies, but I can look up and see them doing it. I have ridden in hundreds of them. Just because I cannot explain it doesn't mean it isn't a fact.

    Have you actually slow smoked a brisket with a temperature probe in it and watched the temperatures throughout the plateau?
  • BacchusBacchus Posts: 6,019
    Anytime graphs are involved in Barbecue, something is just wrong.
  • and worse, he now tells me that my beer can chickens are no good!!! i love my moist and tender beer can chickens better than the alternatives.. . .should i stop doing them now because tweeve tells me that they are just a myth?? and all those steam burns on my arms from the 100+ i've cooked over the past 8 years are a myth as well???!!

    damn, what am i gonna do now???
  • BasscatBasscat Posts: 626
    And he's telling you this less that a day after his son has been born. Just feel very sorry for him, Max. I hope he gets his priorities straightened out. Here's hoping he appreciates his blessings soon.
  • CecilCecil Posts: 771
    EEEK, I had better sign off, I am afraid that I will learn my beloved cheeseburgers are also some sort of hoax!
  • He was the first to respond to the original post, and his sole point was that it was not possible for the temp to drop. That's it.

    About five or six of us replied to the original poster saying that sure,temps can go down during the plateau.

    None of us pretended to know why, but did offer speculation ( which we clearly said was speculation).

    Tweev's issue with us was not that our explanation wasn't accurate, it was that the temp couldn't drop to begin with. There is no reason for him to have an issue with our explanation because he didn't accept the premise in the first place

    all that aside, I can't imagine the frailty of a personality that compels him to post here while his wife is in the 36th hour of labor, or to come back the day his son is supposedly born. I think it's a fabrication and attempt for sympathy. But no serious adult with a newborn would argue with people he has stated he has nothing in common with on s barbecue forum.

    Not unless his entire life is wrapped up in his alter ego

    Newbies take note. As rod mentions, tweev will always revert to acting like the attacked and not the aggressor. He benefits from the fact that ALL of his prior posts have been deleted, because it is easy to forget how giant a disruption he was
  • but what about my beer can chicken?? :(
  • BasscatBasscat Posts: 626
    It rocks! Despite the myths..... (though I like spatchcocked better ;-)
  • Mike in AbitaMike in Abita Posts: 3,302
    It's got a lot to do with Daniel Bernoulli's principle of fluid dynamics. Although I'm pretty sure he's never cooked a brisket on an EGG. :P
  • JeffersonianJeffersonian Posts: 4,244
    For the life of me, I cannot understand why we won't discuss this topic rationally. There is a science to cooking, and this is a perfect example of it.

    I found this an interesting post, but I have another idea as to why the temperature drops. Let me preface this by saying that, while I'm an engineer, I'm a EE and never took thermodynamics, but I've used them in practice during the course of my work since college. So discount what I have to say with that in mind.

    I think you're on to something, but my bet is that the Second Law is just being applied too narrowly here. Might the process at work be an endothermic reaction of the collagen breaking down, drawing heat from the meat in the process?

    Of course, I might be totally full of it, but it strikes me that it may be a hysteresis type thing, like heat of vaporization or fusion in ice.
  • JeffersonianJeffersonian Posts: 4,244
    Dang, I shoulda read your post first. :(
  • ResQueResQue Posts: 1,045
    Nope! Sorry max, your beer can chicken isn't real.
  • JeffersonianJeffersonian Posts: 4,244
    If it includes poultry and Max, it's good. Anyone that sez different is itchin' for a fight!
  • THATHA Posts: 183
    drink the beer and forget the dang chicken. I wonder about eating something that eats with it's pecker. :woohoo:
  • Cactus DougCactus Doug Posts: 341
    I really do not know why, but I have seen this occur sometimes during a cook usually around a 3 deg drop not usually more than 5 deg. Always during the plateau.
  • Yeah, I really like food science. I plan on getting into molecular gastronomy a bit soon but first need to source the appropriate chemicals.

    For example, check this out:

    http://starchefs.com/events/studio/techniques/JAndres/index.shtml

    I had them at a great restaurant in LA a few months ago. Pretty cool stuff.

    I don't have a good answer for the moisture loss with Brisket. I know Fidel made a decent post about how dry food is overcooked food - and that it wasn't really necessary to wrap everything in bacon to retain moisture. Maybe it wasn't him but if so, I think he's right.

    Although everything is better with bacon :)
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