# Ice to "shock" the stock...



## ellohn (Oct 22, 2008)

Hi!

Could anyone please explain (scientifically) to me why you should put a load of ice in the stock pot during the start of cooking when making e.g. chicken stock or lamb stock?
Many "old school" chefs tell you this, and then you ask why, and they say "because it gets better".
In what way does it "shock" the stock?

/ john


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## pete (Oct 7, 2001)

I have never actually heard of this before, but it sounds like taking the idea that you should use cold water in starting a stock to an extreme level. The reason for using cold water, as opposed to using hot, is that by using cold water you get a better extraction than with hot, at least that was always what I had been taught.


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## teamfat (Nov 5, 2007)

I've only heard of using ice later on in the process as an aid to getting the surface fat to firm up so it can be more easily removed. I will say that starting cold and heating slowly is the best way to go. Starting cold, bringing to a boil and then turning down is not the way I'd go. Stocks are clearest and most flavorful when agitation is kept to a minimum.

mjb.


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## chefjohnpaul (Mar 9, 2000)

This is curious. Starting with cold water will allow the albumin to rise in a proper way for the scumming or depouillage. I do not see what ice would necessarily accomplish that cold water would not unless they are blanching and draining the bones first and then trying to bring the temp down again to start cold. I was a saucier for years in a major hotel and have never heard of this technique but all I can think of is better scumming and a clearer stock. Curious.


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## escoffier2250 (Oct 21, 2008)

Isn't it just because you are meant to start with the coldest possible water when boiling root vegetables because of the starch and to not cloud the stock?

I always cold start when blanching or boiling roots, you really can see and taste the difference...try it sometime:lips:


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## koukouvagia (Apr 3, 2008)

I've never heard of that particular use of use of ice although when I make gravy using pan drippings I add homemade stock that I have frozen. When I add the frozen stock it immediately attracts and solidifies the fat making it easier to remove.

The reason I have always started with cold tap water for cooking is because of basic plumbing issues - I'm afraid that hot tap water might be sitting around in the tank for long periods of time while it's heated and may be developing bacteria. Cold water does not have to sit around and be heated therefore it's a steady stream of clean water.


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## ellohn (Oct 22, 2008)

Ok I get it, it´s not a technique known outside this country maybe (working for the moment in Rome, Italy). Here I´ve heard it a couple of times, but never managed to get a good explanation.
Thanks anyway.

The thing with starting cold and going slowly - is that valid for all stocks? Even veal stock etc?
And once it´s started simmering, if you had to add more water, would you add that cold then?

/ j


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## deltadoc (Aug 15, 2004)

I"d never use hot water from the tap. Not because of the possibility of high-heat resistant bacteria living in the tank, but primarily because hot water will hold more water soluble impurities simply because it is hot. And it sits in your pipes after leaving the tank, so it eventually cools down. If there were some dormant bacteria in it, they would probably then find it easier at that point to propagate sitting in the pipes leading to your faucet.

In addition, any crud that has built up in your plumbing would have a chance to contaminate the hot water passing through the pipe much faster than cold water passing through the pipes. And hot water pipes probably build up crud much faster than cold water pipes simply for the reason that the hot water can hold more impurities when its hot, and as it cools down sitting in your hot water plumbing, some of the impurities will precipitate out of solution, thus either creating loose sludge or building up on the interior of the pipes. Again, when "new" hot water starts to flow to your faucet it is conceivable that this new "hot" water will again pick up those impurities and deliver them to your food.

doc


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## ed buchanan (May 29, 2006)

Many years ago when I was serving an apprenticship, and thats over 40 years ago we were told that our consomme when being set up in a consomme pot for clarafication should be done this way. We mixed the mirepoix, meat ,eggshells and whites with ice and put into the pot with the cold stock and God forbid never stirred. We were told that the ice brougtht all of the items used down to the same temperatures and everything could be timed and done evenly. I questioned it then, and question it now, and have over the years made it many times and cannot taste or see a difference either way. It could possibly be an old wives tale???


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## foodpump (Oct 10, 2005)

Although I did my apprenticeship only 20 years ago, I was given the same explicit instructions regarding consomme as Ed, and the same logic behind it. Then, about 8 years ago while working at an upscale French restaurant I was ridiculed by a young French saucier for using Ice in my clarification, and was told that "no one ever did this in France"..... 

For stocks we were always instructed to use cold water for two reasons, the first that starting off in cold wter gave a better flavour extraction, and the second was that starting off with cold water allowed the dead animal protein to form in larger clumps whih could be easier scummed off. 

With all that being said, I have instructed staff to use ice cubes with water when making stock. This was in Singapore, however, and the municipal water(which is very clean and tastes good) is very warm-almost body temperature. The bakers too, would use some ice in thier water, and the larger bakeries would have a water chiller.


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## even stephen (Oct 10, 2005)

Although I am at a loss for the reason....I've always heard that it aided in the process of clarification and filtered more impurities out of the final product. Perhaps the slowness of the stock coming up to temperature allows
more impurities to rise slowly and surely to the top. I vaguely remember someone saying it kept blood from the bones from clouding the stock as well.
I will have to go with the broader range in temperature change allowing for more impurities rising to the raft or layer of fat.....would love for BDL to nail this one down though.....


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## ed buchanan (May 29, 2006)

I was ridiculed by a young French saucier for using Ice in my clarification, and was told that "no one ever did this in France"..... (FOODPUMP)

I was fortunate to work in The Hotel Negressco in Nice .I worked strictly voluntary downstairs in The Chanticlaire Restaurant and they had me put large chunks of ice in the consomme mix. I to once had a young French commis make fun of something I did.
I told him: laugh and say what you want ,but to feed 20 covers here takes 10 of you where as back in the U.S.A, I put out a quality banquet for 600 patrons with 6 cooks. I am 15 years older then all of you and produce twice as much in half the time. He stopped laughing when the ex. chef verified what I said.
One thing you cant beat us on and never will is production'' and time management.


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## pete (Oct 7, 2001)

I have worked under many French chefs, and have been taught many different ways of doing the same thing, each chef telling me that "this is the way we do it in France". The point is that as much as we want to believe and all those "French" chefs want us to believe cooking in France in not nearly as codified as we all think. Not all chefs follow Escoffier to the letter, heck some consider him so out of date that he isn't relevant anymore. There are huge variations in French kitchens as to how things should be done. For example tomato concasse- I have been told by French chefs that it is 1. rough chopped, 2. rough chopped but peeled first, 3. rough chopped but peeled and seeded first, and 4. peeled, seeded and nicely diced. I'm sure someone, in this thread, is going to come along and say, well Escoffier says..... That's not the point, the point is all French restaurant don't live and die by the same exact rules so the next time that snotty, little french cook tells you that that's how it's done in France, just laugh at him.


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## blueicus (Mar 16, 2005)

I've heard another technique of making consomme by freezing stock and them letting it defrost in the fridge, held over a chinois line with cheesecloth. Apparently it makes a product equal to the raft method. anybody tried?


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## even stephen (Oct 10, 2005)

Take it one step further Blueicus.....add limited amounts of gelatin if needed.
Fortified stocks don't really need it because of the natural gelatin...but if your
making, say strawberry, or another fruit consomme, you need the gelatin.....not enough to set it completely, but, enough to form the natural gelatin strands which filter the impurities.......you can actually make any flavored consomme you want....from bacon to blueberry.....blt....anything....you just need an extremely flavor fortified liquid.....its funny you mentioned that.....before posting earlier....the same thing popped into my head....almost mentioned it.....

It makes an incredibly clear product.....its kinda like sucking the color and flavor out of a popsickle......


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## foodpump (Oct 10, 2005)

No matter what method I've tried, making a lobster or fisch consomme is almost impossible, protein is too fine and no matter how carefull you are how much eggwhite you use, you still get a cloudy product. Don't care how many coffee filters or moistened cheesecloths, one guy even tried a pumping filter system designed for home made wines.

One day while taking a fisch stock out of the walk in I got a Grinch-like idea. All the sediment of the stock would settle on the bottom, and the stock--while not a clarified consomme, was pretty darn clear. One slight nudge, however and the whole thing would go cloudy again. I knew that if I tried to siphon off the clear stock with a hose, I'd just disturb the sediment and make the whole thing cloudy again. 

So I poured the stock in a 8 ltr sorbeitier, ran a bamboo skewer through a perforated dishing spoon and put this in the sorbetier, so that the spoon was suspended in the stock (with the bottom of the spoon a good 4" from the bottom of the sorbetier) and the skewer was resting on the rim of the sorbetier, then tossed the whole thing in the walk-in freezer where it took about 6 hrs to freeze. Next morning I ran the sorbetier in some hot water and pulled out the frozen stock out like a popsicle from a mold. All the sediment was frozen in place on the very bottom of the popsicle. Being a tool-freak, I used the meat band-saw to saw off the frozen part containing all the sediment, but you could also set a large pot on the stove and melt off the sediment part, while keeping the frozen clear stock whole.....



But then again I'm the kind of guy who will grease my white garage doors with vulgar margerine samples and get my kids to throw dirt at the greased doors. Most graffitti doesn't stick and the stuff that does, gets power washed off once a year and the grease and flour trick re-applied........


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## ellohn (Oct 22, 2008)

As a said, I´m working in Italy at the moment...
Haven´t been working in France (yet) but I´m pretty sure things are 10 times "worse" here!
People do things a certain way because their grandmother (la nonna) said so or used to do so. They don´t ever question these things and want a scientific explanation. They are waaay behind in this matter. But nevertheless the food is outstanding!


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## allanmcpherson (Apr 5, 2007)

This is now my preferred method. It takes time, two days preplanning perhaps, but with little or no active work time or food cost it is well worth it.

--Al


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## chefjohnpaul (Mar 9, 2000)

If you start a stock in hot water the release of albumen is different than when starting in cold- hot water won't seal anything but it will sure kick out the albumen in a way that does not allow for a good depouillage, you will get a cloudier stock and albumen does not add anything positive to the flavor of the finished product for sure.:smiles:


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## chrislehrer (Oct 9, 2008)

Everything I have read from people I trust, like Pepin and Peterson and so on, fits what chefjohnpaul says here. 

If you start the extraction in cold water, the proteins and albumen tend to drift slowly out and stick to the sides and bottom of the pot. If you start hot, they move more rapidly, do not coagulate in large clumps, and are a great deal harder to skim off: what's more some of it will tend to emulsify into the liquid, and removing this by straining (if possible at all) will take with it some of your stock. If you start cold, raise the heat very slowly, and never quite come to a boil, then simmer super-slow and never disturb the ingredients, you will have a stock that is extremely close to clear right from the outset. If you want perfect consomme, you will still have to do a raft, but for most sauce or soup applications simply chilling the stock to freeze any trace fat, skimming, then reducing if and as necessary will be sufficient. 

The fact that you eliminate the majority of clarification and the like from the process makes this cold-slow system more efficient: not only does it take less time, but your yields are higher, because every straining or clarification is imperfect and absorbs some of your stock.

I cannot see that ice would help at all, unless you have imperfect control over the heat of your hotpoint, which certainly was the case not so long ago. In that case, perhaps adding a bunch of ice would make it take longer to come to the desired near-boil? If that guess is correct, this trick dates from about two generations back, and does not apply to anyone using modern range equipment.

There is an old trick of pouring room-temperature broth that has not yet been defatted through a strainer containing a lot of ice. The idea is that the fat will freeze solid on the surface of the ice and then not pass through the strainer. But unless you have minimal refrigeration space, I think this just makes things more complicated for minimal result: once it's been refrigerated to very cold, all the fat will be frozen on top anyway, and if you've been skimming assiduously there shouldn't be all that much to begin with.

Somebody mentioned seafood stocks. Here the very slow rise in heat works admirably. If the pot takes an hour or more to come almost to the boil, and the liquid started dead cold, very little albumen and protein is going to be emulsified or bound into the stock, and it strains clear.


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## chefjohnpaul (Mar 9, 2000)

Nice thoughts Chris. I had a conversation with Harold McGee on this and it just coinsides with what's happening at the molecular level, as you so eloquently stated. There are also schools of thought that when making stock, like chicken, to not rinse the bones first thus washing away excess albumen, but start process very cold and allow the albumen that is present to clarify the stock as it slowly comes to the simmer and carries particles with it to the surface for depouillage.


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## chrislehrer (Oct 9, 2008)

Clever! So if you do very cold and raise the temp slowly, you're using chicken albumen for the same purpose as egg white (also albumen) in the raft for clarification. Makes sense: I should have thought of that.


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## dc sunshine (Feb 26, 2007)

I'm not sure that I should involve myself in this thread, as I am far from an expert and not qualified to debate in such matters.

But, I would like to report, I decided to make a lamb and chicken stock this week. (Ok couldn't sleep needed something to do!) The weather here is cold at the moment, so the temp of the water from my filter would be about 3 deg C which I started the stock in. It was a bit of an experiment  I had the chicken carcasses and the trimmed lamb chop bones by themselves in the cold water for about an hour, slowly heating till it came to a slow boil.

The albumen came to the surface in nice "solid" pieces - easy to skim, didn't have to repeat the process very often.

Then added the veg etc etc, cooked overnight barely simmering, strained, chilled, took off the fat cap. It was lovely and clear -no need for an egg raft. I would recommend starting very cold anytime. I don't know the technical reasons for it - this thread seemed timely - if my reply has helped anyone I'm happy.

I'll start cold every time now.


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## siduri (Aug 13, 2006)

Hi Ellohn. I live in Rome too - first time i encounter someone else from here on this site. (I can empathize with your coming up against nonna's prejudices all the time - even the doctors will tell you you got a draft (colpo di freddo)! ) Anyway, I have a very off-topic question. Seeing as it's almost impossible to get ice anywhere here, no less in any restaurant i've ever been in, where do they find all the ice???


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## ellohn (Oct 22, 2008)

Mcdonalds?! :lol:


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## ed buchanan (May 29, 2006)

I never recall starting a stock with ice. I was however, always instructed and always did start the clarrification of a consomme from stock to its completion with ice.
The reasons being the same that everyone have already mentioned. It lets the albumin in the bones start to come out later at a more congeeled level so it traps many of the particles extruded by other ingredients, and rises to the top of the consomme pot. :blush:


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## kuan (Jun 11, 2001)

So I guess if you are doing lobster stock it would be consider shellshocked?


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## ed buchanan (May 29, 2006)

That answer is a little fishy!!!:lol::lol:


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## breton beats (Feb 21, 2007)

Yes you should use the coldest water possible for making stock for all the reason listed above, to drive out impurites, also to draw out the.

But the reason many professional chefs add ice to the stock is maybe because that is what they learned in their restaurants. Many restaurants put their stocks on to cook very slowly overnight. The closing shift puts in on, and the opeing shift takes it off. All night it goes at very low heat.

When you have stocks on for too long you run the risk of the vegetables breaking down and imparting bitterness to the stock. So one trick is to start with all ice so that the cooking temperature is delayed, along with the slow heat, and the bones, meat, and vegetables aren't getting too over cooked. (not that it does that too well)

At home I use ice water. That way I know that I am getting the coldest water possible.


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## ellohn (Oct 22, 2008)

Would the same thing (coldest water possible) go for all types of stocks?
Meat stocks as well as fish stocks or maybe lobster?


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## davidturner (Oct 23, 2008)

I've never heard of that particular use of use of ice although when I make gravy using pan drippings I add homemade stock that I have frozen. When I add the frozen stock it immediately attracts and solidifies the fat making it easier to remove.


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## chrislehrer (Oct 9, 2008)

Yes, it should apply to anything with significant protein content. The point is that as the temperature rises, the proteins will tend to coagulate in little clumps. If you start cold and raise the temperature slowly, a great deal of this will stick to the sides of the pot and the chunks of stuff in the water, so it won't float around and cloud your stock or need to be skimmed. This is also why clarification with egg whites works: the egg whites coagulate slowly. Only the thing is, egg whites are almost pure albumen, and you're putting in a fair bit, so they float and coagulate in a mass (the raft), taking all the other coagulated bits with them.

The truly cool trick with lobster, though, is to make crustacean butter. Chop up cooked or raw shells coarsely, heave them in a big stand mixer, and add a lot of sweet butter. Run the machine slowly until everything is stuck together, and then turn up the speed a bit and leave it running for half an hour, by which point the butter will be salmon-colored. Now scrape everything into a big saucepan and add a whole lot of water, like several inches over the top. Bring very gently almost to a boil, then shut off the heat, let cool, and chill. The butter will freeze solid on the top. Remove it in a block, then heat it gently until it starts to sizzle just a little bit and strain it very fine. You now have pure crustacean butter, which freezes in an ice cube tray and keeps for a month or so.

Now make lobster risotto and finish with a cube of this stuff. Heaven!


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## chefhf (Feb 27, 2016)

I realize this is extremely late, googled ice and saw this.

Some chefs say its because it hardens fat solubles to clean the stock better. Stories for days. I worked with a chef that seriously added 1, a single, all by itself, ice cube to a simmer stock. 

The reason I start a stock with ice doesn't have to do with any nonsensical crap wives/chefs - tale. It's simple.

Ice machines filter water very well. You get all the crap out of the tap water. You're making a stock, if you're reducing that stock in say a pork jus, you may taste the chlorine, the fluoride, etc. If you melt ice and drink it, it will taste better than tap water drawn from the same restaurant. I'm not going to buy bottled water to make 20 gallons of chicken stock, but i may use 160# of ice. Depending on the day of the week I can empty my ice machine. Cheaper, cleaner, tastier.

BOOM


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## rpooley (Dec 1, 2015)

I've read Thomas Keller adding ice to the stock once it comes to the simmer, this "shocks" the fat (solidifies) and catches some impurities, making skimming at this stage somewhat more efficient and improving the final clarity.

From the cookbook "Bouchon":

"Place all the bones and the feet, if using, in a 14- to 16-quart stockpot. Cover with the cold water. Slowly bring the liquid to a simmer, beginning to skim as soon as any impurities rise to the top. (It is important to keep skimming, because as the stock comes to a simmer, impurities could otherwise be pulled back into the liquid and emulsify and cloud the finished stock.

Once the liquid is at a simmer, add the ice and then remove the fat. (The ice will chill and thicken the fat and turn it opaque, making it easier to remove.) Skim off as much of the impurities as possible. (Once the vegetables are added, skimming will be more difficult.)"


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## foodpump (Oct 10, 2005)

Mmmm... Thomas Keller or not,  fat doesn't "solidify" at simmering temperatures --say, 75-90 C. 

Oils remain liquid at room temperature, and fats remain solid at room temperatures, was how my gr. 9 science teacher explained it.    And it goes without saying that oil or liquid fat will always float to the top of any liquid--provided it isn't emulsified.

On the other hand, proteins start to coagulate at the mid 60's regardless if they are dead proteins or live proteins.  Scum is nothing more than dead protein, has nothing to offer in terms of nutrition, flavor, or mouthfeel.  The classic theory goes something along the lines of: If you can keep the stock at 65-ish for prolonged periods of time, the dead protein will clump together in larger bits of foam, making it easier to skim off.  Once the temp goes above 90 the dead protein breaks down quickly into tiny bits, making it almost impossible to skim off, and clouding your stock and lending a stale and gritty flavor to it.


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## rpooley (Dec 1, 2015)

I don't shock my stocks, it tends to annoy them and they end up in the therapist's office.  

I was just posting T.K. view of it.  I find that most of the fat comes off with skimming, as long as the liquid is at or just below the simmer.  The rest comes off after chilling in the fridge.

I have found truth in what you say about prolonging the temp at about 65-70 C - those stocks are usually beautifully clear and skimming is a snap.


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