Reason for the stall

[ZILLA]

Basically, I agree with this. It does what it does. As long as it's done right and tastes great, WHO CARES!:becky:

Still, though, it's cool to read this kind of stuff here and then I get to sound like a farking GENIUS when explaining to my friends/family.:heh:

THANKS FOR THE THREAD!

Well it is an interesting idea to discuss. Understanding the science behind the cooking can make a huge difference in outcomes. Can you remember when you first discovered brining? Conversations on osmosis were greeted the same way. Knowing the why's can sometimes be the key to great strides in cooking.

 

[Midnight Smoke]

Cook one at 350º on a rotisserie (or not) and there is no stall. So only cooking Lo-n-Slow is where this process comes into play. :wink:

 

[RichardF]

Lets say for the discussion that we have a perfectly trimmed brisket flat with no surface fat.....The energy released from stored potential energy is in what form? OK, so this change of phase is effecting the five most common types of collagen in meat tissue which makes up 95% of all collagen in meat, and in our case the cell walls at the point they are actually touching each other, parts of the vascular system and so on..... What about the rest of the tissue in the muscle? Why doesn't it change temp? A brisket is not 100% collagen.

it's the same reason you can boil water in a paper cup with a blow tourch. with water and a paper cup, the paper cup stays sufficently cool so as not to burn for as long as there is sufficent water to absorb the energy introduced by the blow torch. while the water is boiling (changing phase) it's temperature will not increase at the pressure of sea level above 213*. once a sufficent quantity of the water has gone from liquid to a gas that it cannot absorb all of the energy as part of the phase change the paper cup will rise in temperature until such time that it starts to burn.

 

[gtsum]

haha..this is all too much for me...Who cares..it is what it is....I think someone else said that earlier???

 

[ZILLA]

Well.... I care, and I think it's an interesting conversation to have. If you don't like it move on to another thread.

 

[Smokesman]

Can we dispense with the back and forth on the merit of this topic and dig in. I for one would like to know the WHY behind the plateau phase in butt and brisket.

This still just tickles the surface of what is going on. It Still leaves one with only a very vauge understanding. The explanations of supercooling or superheating distilled water on you tube are still better. For that matter why an Ice Cream Freezer works is better explained on most internet sites than this is.

We're not done here.....

Speaking of vague...Zilla...I can't tell by your posts if you know the complete answer or need input and or research from the rest of us to fill in the blanks?

I understand the importance of this phase but as I've been increasing my cooking temps into the 275 range I have noticed a shortened plateau phase but as yet with no adverse effect on the final product. Also finding with charting I've done on several cooks that there is NOT a set temp that plateau begins/ends and it often occurs more than once during the cook. Finally, I've read that many cooking at higher temps pull back temps when in plateau to extend this portion of the cook as long as possible. I have yet to try this technique. So the WHY here is important to me!!!

 

[Brauma]

Well it is an interesting idea to discuss. Understanding the science behind the cooking can make a huge difference in outcomes. Can you remember when you first discovered brining? Conversations on osmosis were greeted the same way. Knowing the why's can sometimes be the key to great strides in cooking.

Alton Brown mod. Good point.

 

[ZILLA]

Can we dispense with the back and forth on the merit of this topic and dig in. I for one would like to know the WHY behind the plateau phase in butt and brisket.



Speaking of vague...Zilla...I can't tell by your posts if you know the complete answer or need input and or research from the rest of us to fill in the blanks?

No sir, I do not know the answer to this question. The input so far has brought me to the brink though. I have been able to use some of the key words offered to narrow the searches. Look at the graph I found at this website.

Phase Changes



This graph uses the example of phase change in Ice, to Water, to Steam. A very nice representation.

I'm guessing it's the same for Collagen too.

But here is the rub, again. This graph is for water only. 100% H2-O A brisket is not just water and the temperature of the phase changes are different for both water and collagen. For water the first phase stops at 32*F and the phase for Steam starts at 212*F. In between we have a temperature rise. For Collagen the phase starts at 160* and ends at 180*. The plateau for collagen seems to occur right in the middle of the temp rise from 0*C - 100*C in the water example. So if the Brisket is, lets say 70% water and 30% collagen why does the collegen plateau stop the waters temperature rise, stopping the entire brisket from gaining heat?

 

[ZILLA]

The answer seems to be Equilibrium Between Phases of Matter (Gibbs Law). Very simular to how an Ice Cream feezer works after all. :doh:

The basis for the rule (Atkins and de Paula,[2] justification 6.1) is that equilibrium between phases places a constraint on the intensive variables. More rigorously, since the phases are in thermodynamic equilibrium with each other, the chemical potentials of the phases must be equal. The number of equality relationships determines the number of degrees of freedom. For example, if the chemical potentials of a liquid and of its vapour depend on temperature (T) and pressure (p), the equality of chemical potentials will mean that each of those variables will be dependent on the other. Mathematically, the equation μliq(T, p) = μvap(T, p), where μ = chemical potential, defines temperature as a function of pressure or vice versa. (Caution: do not confuse p = pressure with P = number of phases.)

The rule is valid provided the equilibrium between phases is not influenced by gravitational, electrical or magnetic forces, or by surface area, and only by temperature, pressure, and concentration.


From this link: http://en.wikipedia.org/wiki/Chemical_potential

Chemical potential, symbolized by μ, is a quantity first described by the American engineer, chemist and mathematical physicist Josiah Willard Gibbs. In simplest terms, it is an analogue to electric potential and gravitational potential, utilizing the same idea of force fields as being the cause of things moving, be they charges, masses, or, in this case, chemicals. He defined it as follows:

If to any homogeneous mass in a state of hydrostatic stress we suppose an infinitesimal quantity of any substance to be added, the mass remaining homogeneous and its entropy and volume remaining unchanged, the increase of the energy of the mass divided by the quantity of the substance added is the potential for that substance in the mass considered.

Gibbs noted also that for the purposes of this definition, any chemical element or combination of elements in given proportions may be considered a substance, whether capable or not of existing by itself as a homogeneous body. Chemical potential is also referred to as partial molar Gibbs energy (see also partial molar property).

So the water and the collagen want to reach equalibrium so the temperature rises at the same rate. The water waits for the collagen so to speak.

I hope you light weights didn't get sick and vomit from your migraine headaches while reading this. :becky:

 

[ZILLA]

I'm going to guess that a brisket is homogeneous...

http://en.wikipedia.org/wiki/Thermal_equilibrium#Thermal_equilibrium

Equilibrium is the condition of a system in which competing influences are balanced.

Thermal equilibrium occurs when a system's macroscopic thermal observables have ceased to change with time. For example, an ideal gas whose distribution function has stabilised to a specific Maxwell-Boltzmann distribution would be in thermal equilibrium. This outcome allows a single temperature and pressure to be attributed to the whole system. Thermal equilibrium of a system does not imply absolute uniformity within a system; for example, a river system can be in thermal equilibrium when the macroscopic temperature distribution is stable and not changing in time, even though the spatial temperature distribution reflects thermal pollution inputs.

Global thermodynamic equilibrium (GTE) means that those intensive parameters are homogeneous throughout the whole system, while local thermodynamic equilibrium (LTE) means that those intensive parameters are varying in space and time, but are varying so slowly that for any point, one can assume thermodynamic equilibrium in some neighborhood about that point.


Well I suppose that we are looking at Global thermodynamic equilibrium as thereason that all of the various molecules in the brisket rise in temperature at the same rate.

Thanks guys!!! I really appreciate your input helping satisfy my curiosity about this!!

 

[Mark]

Lots of things happening in addition to phase change. It's more like chaos theory than strict adherence to physics. Perhaps even including the mystic element of thin blue warping the space/time continuum. :roll:

 

[antoant]

I love threads like this one. We might be over thinking something that a lot of people know from experience but if you want to experiment and improve your cooking technique these discussions can save you a lot of trial and error.

No sir, I do not know the answer to this question. The input so far has brought me to the brink though. I have been able to use some of the key words offered to narrow the searches. Look at the graph I found at this website.

Phase Changes



This graph uses the example of phase change in Ice, to Water, to Steam. A very nice representation.

I'm guessing it's the same for Collagen too.

But here is the rub, again. This graph is for water only. 100% H2-O A brisket is not just water and the temperature of the phase changes are different for both water and collagen. For water the first phase stops at 32*F and the phase for Steam starts at 212*F. In between we have a temperature rise. For Collagen the phase starts at 160* and ends at 180*. The plateau for collagen seems to occur right in the middle of the temp rise from 0*C - 100*C in the water example. So if the Brisket is, lets say 70% water and 30% collagen why does the collegen plateau stop the waters temperature rise, stopping the entire brisket from gaining heat?

The answer to your problem is in the fact that heat moves from higher temperature to lower temperature. An example was given in a post higher up but I will give you another example. Let's say that you have just collagen and water, in a 1:1 ratio and they are well mixed togehter. As you reach the phase change temperature of collagen ( which I will assume is approximately 160F ) the collagen starts breaking down. The water on the other hand needs to hit 212F to start stalling and changing to vapor. What happens is the following. As the temperature of the water goes to 161F there is a temperature difference between water and collagen. Thus heat goes from water to collagen to balance the temperature out. As the heat (energy) moves from the water to the collagen the temperature of water drops back to 160F. This process repeats until all the collagen has changed phase and the whole mass starts climbing in temperature together.

 

[Dave Russell]

I'm just wondering whether it's worth the time and trouble to drop the cooker down to "sub boiling point low-n-slow" once the meat hits the stall, or when it completes the stall, for that matter.

I found out yesterday that if dropping the temp around the stall, you might be surprised how long the cook still takes, even if cooking over 275 for the first few hours. I tried it yesterday on a couple butts and a brisket, and didn't time it right, so I had to raise the temp back up for the bbq to be ready for supper.

Anyone tried this?

 

[KnucklHed BBQ]

:blah:

:wacko:



uke:

:mrgreen:

 

[Dave Russell]

So IF dropping the temp down near the boiling point was a way to help reduce moisture loss, there would be no point to it until near the END of the stall?

 

[Dave Russell]

BTW, my brisket didn't stall until 169 yesterday, according to my Maverick.

 

[antoant]

BTW, my brisket didn't stall until 169 yesterday, according to my Maverick.

The temperature you will hit the stall depends on the makeup of the particular piece of meat your are cooking. It will not vary wildly but it does vary between different pieces of meat.

I'm just wondering whether it's worth the time and trouble to drop the cooker down to "sub boiling point low-n-slow" once the meat hits the stall, or when it completes the stall, for that matter.

I found out yesterday that if dropping the temp around the stall, you might be surprised how long the cook still takes, even if cooking over 275 for the first few hours. I tried it yesterday on a couple butts and a brisket, and didn't time it right, so I had to raise the temp back up for the bbq to be ready for supper.

Anyone tried this?

If we assume that the test and texture of good BBQ depends on breaking down the collagen then it seems logical that if you lower the temperature after you hit stall then you are going to break down more collagen than if you had a higher temperature and thus better Q. The other conclusion from the assumption is that after you get out of stall you can raise the temperature as much as you want to get the internal temperature to the proper level in the shortest amount of time.

Then again my assumption is not entirely true. So....

 

[Dave Russell]

The temperature you will hit the stall depends on the makeup of the particular piece of meat your are cooking. It will not vary wildly but it does vary between different pieces of meat.



If we assume that the test and texture of good BBQ depends on breaking down the collagen then it seems logical that if you lower the temperature after you hit stall then you are going to break down more collagen than if you had a higher temperature and thus better Q. The other conclusion from the assumption is that after you get out of stall you can raise the temperature as much as you want to get the internal temperature to the proper level in the shortest amount of time.

Then again my assumption is not entirely true. So....

Assumption or not, if true, I wish I new.:wink:

 

[ZILLA]

No I don't think that will work. The whole thing is based on the equalibrium of the various molecules that make up the meat. You can't change that with heat but you can speed up the plataue time with an increase in temperature and get the same tenderness. That's been proven in many experiments in the meat industry.

What I'd like to do is see if adding something to the meat such as salt will shorten that duration and by how much. Brining a chicken will shorten the cook time of that bird. What can be added to the beef or butt to do the same?

 

[antoant]

No I don't think that will work. The whole thing is based on the equalibrium of the various molecules that make up the meat. You can't change that with heat but you can speed up the plataue time with an increase in temperature and get the same tenderness. That's been proven in many experiments in the meat industry.

What I'd like to do is see if adding something to the meat such as salt will shorten that duration and by how much.

That is true. It is based on the equilibrium of all the molecules. However, as the amount of collagen in the solid phase gets smaller and smaller the temperature of the water will start rising as the heat that leaves the water is not that much any more. So the temperature of the water will rise higher than the temperature of the collagen even if all the collagen has not completely changed phase. If you lower the cooking temperature then you give the collagen more time to change phase before the water starts climbing.

Plus everything that we said so far is based on the assumption that you have just collagen and water. Taking into account that collagen is only 2-6% of most pieces of meat it does not account for the long period it takes to get out of stall. Other things are changing phases too. Unless we breakdown the meat in all its constituents and look each one individually and then in a system you cannot get a clear answer if fast or slow is better. And in the end it is all a balancing act. If you go too fast or too slow the results are not going to be as satisfying.