Cooling rates in water baths, ice baths, etc.

[nathanm]

Nathan - just a quick question about the simulation.  We know that the meat loses water as it cooks.  Is there a difference between the specific heat of cooked vs raw meat?  If so, would its magnitude effect the simulation?

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I do not model temperture dependent diffusivity - which combines both conduction effects and specific heat effects.

People have done the experiments and at these temperatures it is not a significant effect.

It does get to be very significant when you either totally dessicate the food, or when you freeze it. Frozen food has about 4X the thermal conductivity as non-frozen. Specific heat makes a huge change upon freezing due to latent heat of fusion.

[joesan]

Very nice little diversion from the mighty SV thread!

So what is considered the best practice to cool and prepare for refridgeration say, for practical illustration purposes

a. Vegetables

b. Piece of Steak

c. Rib of Beef

d. Whole Duck

Is a stirred bath of coolish water best?

[Ruth]

That seems to be a fairly clear cut experiment then.

Aspargus is out of season here. Lets use say broccoli stalk, one piece cut into two.

So simmer for say 3 mins.

Shock one piece, and leave the other on a plate for say 30 min

The hypothesis is that they will be of different softness, and that suggest time-at temperature is important.

If they are the same softness it might suggest time at temperature is not.

Lets hope as many people try as can, and report here.

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True for both asparagus and broccoli - if not shocked in ice water immediately after cooking they will not only soften but will lose their vibrant color and visual appeal. Both texture and visual appeal are important on a plate. I found the scientific discussion fascinating and learned a great deal from it but we must not forget the ultimate purpose.

[nathanm]

The more I think about this, the more I suspect I am correct about time-at-temperature.  Think about cooking, say, some broccoli pieces in 95C water.  After you put the broccoli in the water, how long can it possibly take before the core temperature of the broccoli is approximately 95C?  Certainly no more than a minute.  And yet, if you pull the broccoli out of the water after 1 minute, it will still be fairly crisp.  Leave the broccoli in the water for 5 minutes, and it will be soft.  What's the difference?  Time-at-temperature.

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You are correct!

[nathanm]

True for both asparagus and broccoli - if not shocked in ice water immediately after cooking they will not only soften but will lose their vibrant color and visual appeal. Both texture and visual appeal are important on a plate. I found the scientific discussion fascinating and learned a great deal from it but we must not forget the ultimate purpose.

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[nathanm]

Very nice little diversion from the mighty SV thread!

So what is considered the best practice to cool and prepare for refridgeration say, for practical illustration purposes

a. Vegetables

b. Piece of Steak

c. Rib of Beef

d. Whole Duck

Is a stirred bath of coolish water best?

←

There are refridgerated water baths and those are great ways to cool things.

Ice water is a simpler way to do it - not quite as good circulation, but cheap and effective.