Cooling large amount of soup (70-100L)

[Edward J]

No, I don't have the last word. Physics law has the last word. One 8 lb ice wand has a very limited heat capacity to cool down boiling soup to food safe temperature for transporting to other locations. 

 

This may work a little better: Replace the water inside ice wands with thermal gel, which has a lot more heat/cool capacity than water, which is why they use it in ice cream makers and to ship food overnight. Let the boiling soup cool it itself down to food safe temperature first, then stir the soup with the frozen gel packed ice wand. Much better end results.

 

Peltier solid state devices can be attached to the pot to cool electronically with no moving parts except heat removal fans. There are many refrigerators you can buy use that device. 

 

There is another very good technology in heat removal which is called "heat pipe", which is in most laptop computers, and in geo-thermal applications, which is very effective to remove a lot of heat in limited space. A "heat pipe" has no moving parts.

 

BTW, a one-ton hoist/lift is less than $50.

 

If it is my shop, I would do anything to save work with a guaranteed end temperature as per Code. Flip the switch on/off. That is all, no stirring stirring stirring, checking checking checking.

 

It was fun speculating. Thanks.

 

dcarch

 

 

O.K. the more I re-read through this thread, the more I see one of two conclusions.  The first is that you can not comprehend the cooling process as explained by me in the last two posts.  The second is that you do comprehend this process, but choose only to acknowledge certain aspects of it.

So, to clarify the whole process, once again, and for the benefit of everyone reading this thread, I will go over it, again.

 

-Finished soup is poured into several15-20lt (4-5 US gallon) mayo buckets.

-Buckets are put into a sink filled with cold water, the water level comes up to or slightly lower than the soup level in the bucket.  The cold water may be augumented with ice, or it may be replenished with fresh cold water as it warms up.

-An ice wand is placed into the bucket

-Ice wand is agitated every few minutes.

-Once soup has hit 10 - 15 C, it is taken out of the water bath, the ice wand removed, and is trucked into the walk-in cooler where cools down further to +- 5 c.

 

Are we clear? 

An ice wand with 8 lbs of frozen water PLUS a water bath is sufficent to cool down a bucket of soup.  This combination of ice wand and cold water bath is endorsed by many municipal health depts.  Please, for gawd's sake, instead of argueing with me, take the time to call up your local health dept. to verify this.  I know it's easier to argue on this site, but, just do it, O.K.?

 

Filling an ice wand with a thermal gel is worth discussing--it's a lousy idea.

 

I do own and use similiar equipment--thermal gel filled plates and blocks (ie Cam-chiller and Cambro lockers) used for transporting food.  However, the gel filled containers never touch the food, and the gel-filled containers do not go through extreme temperature swings like an ice wand does.

 

The icewand goes from -20 C in a frozen state straight into hot liquids of around 90C in a matter of seconds, but more importantly the wand is in immediate contact with food.  After repeated cycles of this freeze and thaw temperature swings, the plastic on the icewand will fatigue and crack.

-If the icewand is filled with clean, potable water and it leaks, it's not a big deal.

-If the icewand is filled with glycol or some other thermal gel and the wand leaks, at worst you may poison people and at the very least, you have to throw out the soup.

 

Mr Pepin's method of adding ice to concentrated soup is also worth discussing.  This method, which Mr. Pepin writes was used by him in the Howard Johnston Kitchens and in the World trade Center (NYC) kitchens was developed for large batches.  With this method you have to use very precise amounts of salt, seasonings, and liquid.  Once the soup has cooled down, tasting and adjusting salt/flavour levels is very difficult.

 

Yes, heat pipes and geothermal equipment are good ideas.  But at what cost?  In order for a heat pipe to work you have to pump liquids through it. This means cleaning and sanitizing a pump and other equipment, provided you can pump a 3-bean soup or a chunky chicken noodle soup throught the heat pipe.

 

So, to recap, Icewands in combination with cold water baths work well.  So well, that this method is endorsed by many municipal helath depts.  The method is very cheap, very effective, and has a proven track record.

[dcarch]

With all due respect, I disagree with you – (my words in red)

 

“ -Finished soup is poured into several15-20lt (4-5 US gallon) mayo buckets. (7 buckets needed for 100 L of soup in total)

-Buckets are put into a sink filled with cold water (for 7 buckets of soup), the water level comes up to or slightly lower than the soup level in the bucket.  The cold water may be augumented with ice (make ice, add ice), or it may be replenished with fresh cold water as it warms up (add some more water).

-An ice wand(s) is placed into the bucket(s)

-Ice wand is agitated every few minutes. (for all 7 buckets, change ice wand again and again)

-Once soup has hit 10 - 15 C, it is taken out of the water bath (all 7 buckets), the ice wand removed (washed and sanitized, and find a clean place in the freezer to be re-frozen), and is trucked into the walk-in cooler where cools down further to +- 5 c. “ (7 buckets to be washed and sanitized)

 

Are we clear? 

I am very clear that you feel all the above is simpler and easier than flipping one switch on and then off on the refrigeration machine.

 

Please, for gawd's sake, instead of argueing with me, take the time to call up your local health dept. to verify this.  I know it's easier to argue on this site, but, just do it, O.K.?

 

No need to call. I don’t think I ever argued with you for one second that the clumsy method is approved by the health department. The question is will they disapprove a cleaner, easier and more precise temperature control system.

 

Filling an ice wand with a thermal gel is worth discussing--it's a lousy idea.

 

--------  However, the gel filled containers never touch the food, and the gel-filled containers do not go through extreme temperature swings like an ice wand does.

 

Sorry, you are wrong. The gel packs touches food all the time, the last time I ordered steak. They are rated for extreme temperatures for both cold and hot use.

 

-If the icewand is filled with glycol or some other thermal gel and the wand leaks, at worst you may poison people and at the very least, you have to throw out the soup.

 

Wrong again. The gel is rated non-toxic.

 

Yes, heat pipes and geothermal equipment are good ideas.  But at what cost?  In order for a heat pipe to work you have to pump liquids through it. This means cleaning and sanitizing a pump and other equipment, provided you can pump a 3-bean soup or a chunky chicken noodle soup throught the heat pipe.

 

You are completely 100% wrong about heat pipe operations and principles.

 

-----------------------------------------------------------------

 

Enough entertainment for other members. Reporting the following experiment I just conducted, and this will be my last post on this topic.

 

I boiled 10 lbs of water.

I froze 1 lb if ice.

 

Thermapen measured water temperature to be 210 F (evaporation cooling from 212 F)

 

Infrared remote thermometer measured ice to be 4 F

 

Melted ice in hot water. Water measured 188 F afterwards.

 

In other words, for 220 lbs of soup, 22 lbs of ice can only bring the temperature down to 188 F. Most likely the soup will be hotter than 212 F when it is boiling, because of the salt contain and the oil will prevent evaporation cooling.

 

Now I have a lot of respect for the Soup Nazi. LOL!

 

dcarch

 

[Edward J]

Did you put your hot water test in a  cold water bath in conjuction with the ice?

 

 

Conclusion:

 

 

You comprehend the principle of cooling down hot liquids.  Heck, ya gotta, it's been explained three times now very clearly,  you just choose not to do the test according to the described procedure.

[MelissaH]

MelissaH, that is a very clever way. Jacques is always clever. However, I think his method is to cool the soup down for immediate consumption, not for food safe handling based on health inspector's requirements, which, here in the USA is to be colder than 40F.

 

dcarch

 

Actually, no. According to page 216 of my hard cover book (near the beginning of chapter 14, if you have an ebook), he says, "The finished soups were to be placed on the shelves of the walk-in cooler so the older soups were used first." After a sentence or two, he continues, "Demand would require that we produce 150 gallons of hot soup each morning, but the containers couldn't go directly into the fridge because their heat would quickly turn the fridge into a sauna. We didn't have the money or the space for special equipment to cool the containers rapidly."

 

So they were definitely cooling the soup for storage, not for immediate consumption.

[dcarch]

MelissaH, I idolize Jacques. I have met him a few times. He is more than a chef. I encourage everyone to Google “Jacques Pepin, artist, painter” He is a museum quality artist.

 

His method can work very well. 150 gallons of soup made his way can be 100 gallons of concentrated soup, then add 50 gallons of ice, then into the cooler. The time the soup spends in the “Danger Zone” may be acceptable.

 

I know many people have problem with this, but I am not the only one. For my personal use, I frequently make soup, cover the soup, and leave the soup overnight on the stove. 212F basically sanitizes the soup.  (Yes, I know about autoclave temperature is required for true sanitizing). A large pot of boiling soup in the refrigerator can totally mess up the thermostat for many days.

 

dcarch

[Edward J]

 

I know many people have problem with this, but I am not the only one. For my personal use, I frequently make soup, cover the soup, and leave the soup overnight on the stove. 212F basically sanitizes the soup.  (Yes, I know about autoclave temperature is required for true sanitizing). A large pot of boiling soup in the refrigerator can totally mess up the thermostat for many days.

 

dcarch

 

 

Ummm, no.. a large pot of boiling soup in the refrigerator won't mess up the thermostat.  If you understand the basic of refrigeration, the compressor compresses gas, and the gas is allowed to expand in the evaporator coil.  When you put hot items into the fridge, steam rises and collects on the coil.  The coil, being cold, will freeze the steam, icing up the whole coil.  The refrigerator can not function properly now, the temperature goes up, and the compressor shuts down.  The big difference between residential refrigeration and commercial is that commercial goes on a defrost cycle every 8 hours.  This allows any ice on the coil to melt off.  This is also why any Chef or owner will not allow hot foods to put into the refrigerator or freezer

.

Sanitizing is one thing, allowing food to dwell in the hazard zone for 4 hours or overnight is another. 

 

Am I right in assuming you did your test as described in your post #27 (written in red) without using a cold water bath?

[emannths]

dcarch, I'm with you.  You can't beat thermodynamics.

 

I like looking to wort-chilling for inspiration.  You can hook up two of them together with a pump and stick one in the soup and one in an ice-water bath.  You'll still need a couple hundred pounds of ice (or lots of cold water).  The nice thing about this setup is that you can easily switch from ice-chilled to compressor-chilled in the future if you want.  Just make sure you stay clear of wort chillers that have you pumping the wort (soup) instead of just the cold water.

 

Another alternative?  Use liquid nitrogen and a big mixer.  Your hot soup will splatter everywhere, your employees will asphyxiate, but the youtube video will get tons of hits.  And your soup will get cold.

[dcarch]

Ummm, no.. a large pot of boiling soup in the refrigerator won't mess up the thermostat.  If you understand the basic of refrigeration, the compressor compresses gas, and the gas is allowed to expand in the evaporator coil.  When you put hot items into the fridge, steam rises and collects on the coil.  The coil, being cold, will freeze the steam, icing up the whole coil.  The refrigerator can not function properly now, the temperature goes up, and the compressor shuts down.  The big difference between residential refrigeration and commercial is that commercial goes on a defrost cycle every 8 hours.  This allows any ice on the coil to melt off.  This is also why any Chef or owner will not allow hot foods to put into the refrigerator or freezer

.

Sanitizing is one thing, allowing food to dwell in the hazard zone for 4 hours or overnight is another. 

 

Am I right in assuming you did your test as described in your post #27 (written in red) without using a cold water bath?

 

First I said I will not continue to discuss further with you on the previous topics, which were mostly about laws of physics, as beating a dead horse may be objectionable to some members. 

 

I am afraid again to disagree with you on this new topic, I am sorry to say that you are wrong again.

 

A typical residential refrigerator uses only one compressor for both the freezer and refrigerator. The thermostat, depending on the model, uses different designs to balance the temperature between the two. To complicate the matter, the thermal mass of food stored in the two compartment varies. If you read the instructions which come with the refrigerator, you will be instructed to wait a few days each time you adjust the temperature to give time for the balance to re-establish.

 

And by the way, What do you mean by the difference between a commercial refrigerator vs. residential? Most home refrigerators are also frost-free. The defrost cycle using hot air goes on a timer, typically 6 hours.

 

A large pot of boiling soup will confuse the thermostat for a few days, depending on how much food is in the freezer and in the refrigerator.

 

dcarch

[paulraphael]

I think I see the disconnect here. Dcarch's numbers are correct, but they don't seem to be accounting for all of the circumstances.

 

First, the ice is only one vehicle among several cooling the soup concurrently. The others include evaporative heat loss and conduction though the sides of the containers. The speed / efficiency of these cooling modes is proportional to the temperature difference between the soup and the environment, so it will proceed very quickly on its own in the beginning, especially if the soup is transfered to a number of smaller containers (which increase surface area for both evaporation and conduction). 

 

Placing the the buckets in a water bath in the sink will speed this process even more. Depending on time constraints, you may not even need the ice wands until the soup temperature drops below 140F (at which point you want to minimize the cooling time, and also at which point the temperature differential is going to be helping the process less).

 

Another difference between the theoretical model and the actual soup: soup is not 100% water. Unless you're making ammonia soup, every non-water ingredient has a lower specific heat than the water. All those starch and protein and fat molecules store less energy per gram. While a viscous or chunky soup may impede convection more than a pot of water, it will in fact require less energy transfer—and therefore less ice.

 

It would still seem you'd need a lot of ice. Just not the crazy amount suggested by the Pysics 101 scenario.

Edited March 12, 2014 by paulraphael (log)

[Edward J]

Thank you !

 

Now, can you please explain why it's not a good idea to leave a pot of freshly boiled soup, with a lid on it, on the stove overnight?

[paulraphael]

Thank you !

 

Now, can you please explain why it's not a good idea to leave a pot of freshly boiled soup, with a lid on it, on the stove overnight?

If your covered soup pot were as well sealed as a canning jar, there wouldn't be any issues. 

 

But it isn't. As the soup cools, the air above the soup will cool and contract, sucking outside air into the pot. This outside air isn't sterile (at least not in my kitchen) so you'll be introducing microbes. Once the soup cools below 130F or so, it becomes microbe food, and by the time it reaches room temperature, it's a microbe feast.

 

It's best to leave the lid off, to hasten evaporative cooling. Between this and water bath, you can usually get a small batch of soup cool enough to put it in the fridge in a reasonably safe amount of time.

 

This winter I've been making a lot of soup in 7qt dutch oven, and have relied on our various polar vortices for rapid cooling. When it's 15° out, you just put the covered pot out the patio / snow/ roof / fire escape, and it will be cool enough to put in the fridge within a couple of hours.

[dcarch]

Back on topic, just for fun to speculate:

 

I mentioned that "Heat Pipes" are used in many application for fast heat/cold transfer with no moving parts.

 

And, a Peltier junction device is a solid state electronic cooling device with no moving parts.

 

If you merge the two into a stirrer, that would be a very interesting stirrer for cooling soup.

 

It gets better, those of you who have one of those personal refrigerators, which use Peltier device for cooling, not compressors, may know that the Peltier device is reversible. By flipping a switch to change polarity, the same refrigerator becomes a heater. How about you can use the same stirrer to cool or to heat up the soup?

 

dcarch

[Lisa Shock]

Thank you !

 

Now, can you please explain why it's not a good idea to leave a pot of freshly boiled soup, with a lid on it, on the stove overnight?

 

HERE's Harold McGee on the topic.

[Edward J]

Good ol' Mr. Mcgee, he can explain it better than anyone else.

 

If I ever caught an employee doing that( leaving an pot of soup on the stove with a lid on it) I wouldn't bother explaining why it's wrong to do that  to the employee, it's food safety 101.  No, I'd fire his/her (deleted) on the spot, and would seriously consider calling the cops with attempted manslaughter charges (poisoned soup...)

[paulraphael]

One issue is that I really don't want to boil any of my soups or stocks for an additional 15 minutes. Most of my soups have ingredients that will overcook, and all stocks and broths lose aromatics with continuous boiling. Sometimes this is a tradeoff you have to make in order to to concentrate non-volatiles by reduction. But I'm not going to make that tradeoff because I'm too lazy to cool the stock properly.