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nathanm

Cooking with Liquid Nitrogen

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Art   
I just talked with Art.  He is out at the Bonneville Salt Flats sending rockets into space.  I think he is a bit of a mad scientist!

Yes, yesterday was spent out on the Bonneville Salt Flats launching rockets. (These are really big rockets -- not those little Estes toys that we all grew up with. Some weigh over 100lbs and fly up to 17,000 feet or so. You have to get FAA clearance in order to fly this high. About two or three miles away, was the "racetrack" which is just as flat as where we were. We could watch cars zoom back and forth at 200mph+

See these links to see some of the more impressive rockets that were launched yesterday:

http://uroc.org/index.php?option=com_conte...1481&Itemid=715

http://uroc.org/index.php?option=com_conte...=528&Itemid=715

Fun fun! Came home and spent the rest of the evening working on getting our new (well, built in the late 20's early 30's) melangeur going. There are some slight mechanical problems that have to be worked out before we can use it in production. It is a very beautiful machine though. In fact, it looks almost exactly like the melangeur in the "Avatar" engraving I use that shows on the left side of my posts.

-Art


Edited by Art (log)

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YPants   

read a bit in On Food And Cooking today and it said something along the lines that when you freeze meat, ice crystals forms that kinda punctures the cellular walls and makes the liquid loss during cooking increase.

i know making ice cream with liquid nitrogen eliminates ice crystals, so does the same thing work with meat? would it be worth it at all?

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hongda   

It's not that freezing via liquid nitrogen does not produce ice crystals, it's just that the ice crystals are smaller. The slower something freezes, the bigger the ice crystals, and analogously, the faster something freezes the smaller the ice crystals. I think it would depend on the choice of meat. If the piece of meat is large, the liquid nitrogen won't be effective in freezing it quickly.

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s0rce   

as a side note it is possible to freeze water without forming crystals at all, this is often done by submerging very small samples into liquid ethane (freezes things substantially fast than liquid nitrogen). This vitrifies the sample, effectively maintaining the disordered liquid state but as a solid.

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YPants   
It's not that freezing via liquid nitrogen does not produce ice crystals, it's just that the ice crystals are smaller.  The slower something freezes, the bigger the ice crystals, and analogously, the faster something freezes the smaller the ice crystals.  I think it would depend on the choice of meat.  If the piece of meat is large, the liquid nitrogen won't be effective in freezing it quickly.

yeah well nitpicking aside, i think it would be pretty sweet if u could actually freeze, say, salmon fillets or duck or whatever and actually have it thaw up nicely. kinda surprised there isn't more experimentation regarding this. i don't have access to liquid nitrogen sadly, was just curious.

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Tri2Cook   

BLATANT UNSAFE INFORMATION WARNING: Do you have access to dry ice? If so, break up some into small chunks, put it in a container (not glass) and slowly pour some 190 Everclear in. Let it sit until it quits "boiling" (doesn't take long) and experiment away. This won't be as cold as LN2 (only about -100 f) and in some ways it's less safe (it won't roll off of your skin like LN2 so don't try the little dunking your fingers to move things around thing you see some people do with liquid nitrogen, use tools or cryo gloves and try not to let it drip on you when you remove things from the tank). It does make an effective and fun way to play with quick freezing things though. If you're going to freeze food items that are sealed in plastic and won't be in direct contact with the liquid you can use isopropyl alcohol instead of the Everclear (much cheaper).

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http://www.telegraph.co.uk/news/worldnews/...n-accident.html

The 24-year-old chef was experimenting with a recipe involving liquid nitrogen, which is used by chefs including Heston Blumenthal to freeze food, when there was suddenly an "enormous explosion", according to a report in the Berliner Morgenpost.

The young man, from Stahnsdorf, near Berlin, lost one hand in the explosion, which occurred at his girlfriend's mother's house.

He was rushed to hospital, where his other hand was amputated and his condition was described as life threatening and he remained on artificial respiration. <snip>

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I know people who use liquid nitrogen as part of a medical/scientific company, and they have a lot of protocols for handling the nitrogen, canisters, and receptacles. (and they were making ice cream with it back in the 1960's) I get worried when I see people handling it in kitchen situations without safety gear, and using inappropriate containers for the nitrogen and the super-cooled resulting products.

Even really good restaurants occasionally do dumb things (I've seen the youtube videos) with it like dipping 100% metal spoons into a bowl of the liquid while the spoon is being held in a bare hand, or not wearing protective eyegear.

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For those that are interested, there is a detailed article (in German) found here.

The money quote is this:

Vermutlich explodierte das Behältnis, weil der Druck darin durch die Erwärmung der Flüssigkeit massiv gestiegen war.

In other words, the liquid nitrogen caused the container it was in to explode, because of the pressure buildup. This is why it is important never to put liquid nitrogen into a sealed container! The German article is, in this and other respects, far from the fear-mongering nonsense that's been propagated in the English-language press.

The article notes that his left hand was ultimately saved, not amputated as previously reported. Also, it's probably important to note that he was working in a house, not a professional kitchen, at the time of the explosion.


Edited by mkayahara (log)

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Tri2Cook   

Thanks mkayahara. I was interested in the additional information because the first article left me thinking WTF? It just didn't add up with the information they reported. The stuff doesn't just randomly suddenly explode for no reason at all. An inappropriate container is a whole different jar of gas though.

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I seriously doubt any analysis by any news reporter regarding energetic materials. They usually only manage to get their own name correct.

This article came to me via a chemical engineer. There seems to already be a huge hole in the story including the good news that they saved one hand. Meanwhile everyone covers up what they did so we may never find out what actually went wrong. It's all in the name of safety.

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I can't speak for the article, but in general find that people who work with LNO2 don't respect its dangers as much as they should. This includes friends who are chefs, and friends who are molecular biologists!

Everyone I know is clever enough to prevent an explosion. What's worrisome is lack of eye protection (a small splash in the eyes is bad, bad news) and lack of respect for the problems associated with spills.

There are issues with big spills in enclosed spaces (suffocation). But a more likely problem is small spills that get inside your clothes. People get lulled into complacency by the cool way a blob of nitrogen just beads up and rolls off your hands. They don't stop to think about what happens if it falls inside your shoe and has nowhere to go. The result can be excised, frostbitten flesh, or amputated toes.

At a minimum, people should where lab goggles, roll up their sleeves, and kick off their shoes (or wear open shoes like flip flops).

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blais   

First off. Liquid nitrogen is dangerous. Frying oil is dangerous. Boiling water, pressure cookers, gas grills, fire, knives etc.

E-gullet can be dangerous as well obviously.

Please do not suggest to wear flip flops while working with liquid nitrogen. If you are supposed to wear gloves and goggles to be safe, then lets please suggest that people wear shoes and socks.

And, a drop of nitrogen in your shoe will not cause you to lose your toes or get frost bite.

But go pour some on your feet in flip flops and you could get burned.

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Please do not suggest to wear flip flops while working with liquid nitrogen. If you are supposed to wear gloves and goggles to be safe, then lets please suggest that people wear shoes and socks.

And, a drop of nitrogen in your shoe will not cause you to lose your toes or get frost bite.

But go pour some on your feet in flip flops and you could get burned.

I strongly disagree. Regular shoes and socks are the least safe thing to wear with liquid nitrogen. You're right that a drop in your shoe won't cause frostbite, but a big splash most certainly will.

There are two safe approaches: protective gear (boots that won't let any liquid in, with an apron or cuffs covering the tops) or no gear at all. Spilling LN02 on bare feet won't hurt you ... it rolls off just as it rolls off your hands. Flip flops are the same.

If you're in a commercial kitchen, obviously bare feet and flip flops are not going to fly ... but working with it at home, that's exactly what I'd do.

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You must be a lot less klutzy than I am! :biggrin: If the options are full protective gear or barefoot, I will absolutely choose protective gear. There are other dangers in even a home kitchen than the liquid nitrogen. Like, the heavy bowl full of that fresh ice cream that I just dropped on my foot. Doh!

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blais   

you used the word amputated ? And you did say if it fell in your shoes you would get frost bite.

And what's the difference if your at home or in a professional kitchen ? If your cooking then you could spill oil, drop a knife, etc ? Both more dangerous.

And now you suggest to either wear boots, BTW, I've dealt with plenty of LN2 and never in 6 years under the most corporate of circumstance been asked to wear boots. Or, wear no protective gear.

wouldn't wearing partial protective gear be partially safer ?

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troyml   
you used the word amputated ? And you did say if it fell in your shoes you would get frost bite.

And what's the difference if your at home or in a professional kitchen ? If your cooking then you could spill oil, drop a knife, etc ? Both more dangerous.

And now you suggest to either wear boots, BTW, I've dealt with plenty of LN2 and never in 6 years under the most corporate of circumstance been asked to wear boots. Or, wear no protective gear.

wouldn't wearing partial protective gear be partially safer ?

I've had very little actual experience with LN2, but I can see why street shoes would offer little to no protection from a LN2 spill. The liquid nitrogen rolls off when spilled on bare flesh because it rapidly forms a layer of nitrogen gas upon which it floats and provides an insulating effect. In a standard shoe the porous, absorbent nature of the materials shoes are made of would hold the LN2 in contact with the skin where it could cause frostbite. Bare feet, or flip-flops allow the nitrogen to escape, where it is not held in contact with the foot.

I am not saying don't wear shoes and socks in the kitchen. I had an interesting triangular burn on my foot for sometime because I dropped a slice of pizza that had freshly come out of the oven onto my bare foot in my home kitchen. It was an entertaining sight watching me run to the bathroom where I shoved my hot cheese coated foot under the bath spigot.

I'm pretty certain that what happened here was a pressurized vessel exploding. It says he stole the LN2 from his place of employment and I think it highly likely he did not have a Dewar with which to properly transport and store it. So if he put it into a regular vacuum thermos then the pressure would build without release until the thermos ruptured.

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From the Compressed Gas Association:

Heavy leather protective gloves, safety shoes, aprons, and eye protection must be worn to prevent possible contact with . . . the cold liquid or boil-off vapors which may result from spilled or splashed liquid.
Equipment and systems designed for the storage, transfer, and dispensing of cryogenic liquids . . . must be equipped with pressure relief devices to prevent excessive pressure buildup do to the vaporization of the cryogenic liquid as heat leaks into the system.

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And what's the difference if your at home or in a professional kitchen ? If your cooking then you could spill oil, drop a knife, etc ? Both more dangerous.

I don't know about your home kitchen, but mine is a controlled environment. I'm usually in it by myself, the pace is measured, and I won't get kicked out for failing to comly with the chef's (or OSHA's) rules. If I'm wearing flip flops, which I often do on hot summer days while cooking, I'm all the more careful when tossing food in a hot pan.

BTW, I've dealt with plenty of LN2 and never in 6 years under the most corporate of circumstance been asked to wear boots. Or, wear no protective gear.

Then you're working for people who don't observe even the most basic industry safety rules and recommendations.

wouldn't wearing partial protective gear be partially safer ?

Yes. But street shoes are not protective gear, partial or otherwise, with LN2. They're a hazard. Like wearing a neck tie around a printing press.

(Edited to add: in previous post I wrote "LNO2," which may or may not exist. I meant LN2)


Edited by paulraphael (log)

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From the Compressed Gas Association:
Heavy leather protective gloves, safety shoes, aprons, and eye protection must be worn to prevent possible contact with . . . the cold liquid or boil-off vapors which may result from spilled or splashed liquid.
Equipment and systems designed for the storage, transfer, and dispensing of cryogenic liquids . . . must be equipped with pressure relief devices to prevent excessive pressure buildup do to the vaporization of the cryogenic liquid as heat leaks into the system.

This topic seems to have skidded off course. The cryogenic properties of LN2 have no bearing on how some guy in germany lost his hands mishandling the stuff.

The last major incident I could find involving LN2 was a midnite explosion at Texas A&M where the tanks were old, decrepit, and had improperly installed stress relief valves.

It would appear to me that this guy had somehow put the LN2 under pressure or caused it to expand to a volume greater then his container could release the pressure. We can only guess as to what he was doing, but several reports I read indicated that he had taken the LN2 into the bathroom where the container "Blew up". I can only guess that the guy must have added a too warm liduid to the LN2 container to get that type of effect. Or maybe he attempted to flush the LN2 to dispose of it after he was finished using it and it became compressed in the pipe after passing the elbow shaped gas trap.


Edited by RAHiggins1 (log)

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dougal   
...

It would appear to me that this guy had somehow put the LN2 under pressure or caused it to expand to a volume greater then his container could release the pressure. We can only guess as to what he was doing, but several reports I read indicated that he had taken the LN2 into the bathroom where the container "Blew up". I can only guess that the guy must have added a too warm liduid to the LN2 container to get that type of effect. ...

Maybe he just screwed on the top of his ordinary thermos flask, to close it up nice and tight and stop his magic toy leaking away ... ?

It would be quite easy to "explode" any normal container, just by closing it.

Every 56 grams of N2 would like to be 22.4 litres of gas at about room temperature. (Avogadro.)

Translating that into US units, each 2 oz would make about 6 US Gallons of gas. Potentially quite quickly ...

There was a US Administration official who said it badly, but regardless of everything else he may ever have said, he was actually exactly right that it is what you don't know that you don't know that is dangerous.

Ignorance is bliss. But usually not for long.

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Maybe he just screwed on the top of his ordinary thermos flask, to close it up nice and tight and stop his magic toy leaking away ... ?

It would be quite easy to "explode" any normal container, just by closing it.

Yup!

Imagine a thermos with a glass vacuum bottle ...

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...

It would appear to me that this guy had somehow put the LN2 under pressure or caused it to expand to a volume greater then his container could release the pressure. We can only guess as to what he was doing, but several reports I read indicated that he had taken the LN2 into the bathroom where the container "Blew up". I can only guess that the guy must have added a too warm liduid to the LN2 container to get that type of effect. ...

Maybe he just screwed on the top of his ordinary thermos flask, to close it up nice and tight and stop his magic toy leaking away ... ?

It would be quite easy to "explode" any normal container, just by closing it.

Every 56 grams of N2 would like to be 22.4 litres of gas at about room temperature. (Avogadro.)

Translating that into US units, each 2 oz would make about 6 US Gallons of gas. Potentially quite quickly ...

There was a US Administration official who said it badly, but regardless of everything else he may ever have said, he was actually exactly right that it is what you don't know that you don't know that is dangerous.

Ignorance is bliss. But usually not for long.

A thermos, glass or not, would not keep it at room temperature. It would keep it much colder than that since it is in fact an insulated container. I've seen plastic containers that had LN2 poured into it become brittle while frozen. But if a thermos were dropped, what would happen?

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It is making more sense now.

Looks like he brought it home in an ISI Siphon or the like (sealed). He then proceeded to try to open said (pressurized) siphon with a screwdriver in the bathroom (why) of his girlfriend's apartment. I'm guessing he had the siphon between his knees at the time since the explosion blew a chunk out of one of his calves and also did significant damage to his naughty bits. Talk about adding insult to injury the local police also will be pressing charges against him.

If not a darwin award winner certainly a runner up.

...Währenddessen wurden neue Details zum Hergang des Unglücks bekannt... Martin E. soll sie in einem Sahnesiphon – einem druckfest verschließbaren Gefäß – in die Wohnung seiner Freundin gebracht haben, für einen solchen Transport ist der Siphon ungeeignet.

Im Badezimmer habe der Koch dann versucht, den Stickstoff umzufüllen, das Gefäß stand wahrscheinlich bereits unter hohem Druck. „Offenbar hatte er versucht, den verschlossenen Siphon mit einem Schraubenzieher aufzuhebeln“, so Laurisch. Dabei kam es zur Detonation, das Badezimmer brannte völlig aus. Gegen den Koch werde nun strafrechtlich ermittelt, sagte Laurisch. „Wenn die körperlichen Schäden über das hinausgehen, was er angerichtet hat, werden solche Verfahren aber gemeinhin eingestellt.“

full article

More on the extent of his injuries


Edited by 6ppc (log)

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