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nathanm

Cooking with Liquid Nitrogen

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The only "pros" with LN2 I know are the ones that work for the LN2 companies. I go through 1,000 litres of LN2 every week. Thats enough to be considered a pro, but I am far from a pro when it comes to the knowlegde the scientists have. I can tell you LN2 is no more hazardous that working with gas burners. One just has to be careful to have adequete hvac and dont keep your hands in the thick fog or liquid for too long. The rules of engagement are similar to a gas flame. If anything, gas is MORE dangerous because it can blow up the kitchen if youre not careful.

That's a little ridiculous. People are not blowing up kitchens with any regularity.

Telling people not to wear gloves and goggles when working with Ln2 is irresponsible.

That just proves my point, kitchens dont blow up just like only someone who has no idea what they are doing will injur themselves with LN2. Do we work with gloves when we cook or wear a mask when we pan fry to prevent oil from splattering into our eyes? No, but accidents happen. Ever heard of someone in a kitchen losing a finger or getting a 3rd degree burn because of LN2? I have not. Thats not to say we arent extrememly careful when we work with it. We are very respectful of the element, just like we are careful when working with any gastro techniques/devices.

This is like SARS in my book, more people have died from drunk drivers in the past 60 seconds than the entire history SARS has existed, yet everyone freaks out when they hear about SARS.

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Liquid N2 can also supposedly be obtained from welding suppliers.

I have burned myself when using liquid nitrogen in the lab. It sputters when you add wet items to it. However- the saving grace to not frequently hurting yourself with it is that it evaporates very quickly.

Also, proper liquid N2 gloves do not absorb the stuff. The gloves are neccesaary as the liquid N2 vapor is extremely cold as well. In fact, it is the vapor we use to keep our samples in the lab frozen, rather than submerging them in the liquid. The liquid is too prone to contamination issues.

An additonal safety mention- liquid N2 is explosive if contained in a traditional home /food thermos or any sealed container. All containers holding liquid N2 must have a vent release.

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That just proves my point, kitchens dont blow up just like only someone who has no idea what they are doing will injur themselves with LN2. Do we work with gloves when we cook or wear a mask when we pan fry to prevent oil from splattering into our eyes? No, but accidents happen.

This really isn't a very valid argument. Body temperature is 37C. Frying oil is typically something like 190C, for a difference of 153C. The boiling point of liquid nitrogen is -196C, for a difference of 233C. In order for there to be an equivalent difference in temperature, the frying oil would have to be 270C, aka 518F. Do I think that people should wear safety gear if they are working with an oil at 518F? You bet I do. Liquid nitrogen also has a significantly higher specific heat than typical frying oils. What this all means is that being hit in the eye with a splatter of LN2 would be much worse than being hit in the eye with a splatter of oil from a fryer. Somehow I have a hard time imagining someone working with their bare hands a few inches above the surface of a 518F fryer.

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That just proves my point, kitchens dont blow up just like only someone who has no idea what they are doing will injur themselves with LN2. Do we work with gloves when we cook or wear a mask when we pan fry to prevent oil from splattering into our eyes? No, but accidents happen.

This really isn't a very valid argument. Body temperature is 37C. Frying oil is typically something like 190C, for a difference of 153C. The boiling point of liquid nitrogen is -196C, for a difference of 233C. In order for there to be an equivalent difference in temperature, the frying oil would have to be 270C, aka 518F. Do I think that people should wear safety gear if they are working with an oil at 518F? You bet I do. Liquid nitrogen also has a significantly higher specific heat than typical frying oils. What this all means is that being hit in the eye with a splatter of LN2 would be much worse than being hit in the eye with a splatter of oil from a fryer. Somehow I have a hard time imagining someone working with their bare hands a few inches above the surface of a 518F fryer.

I can dunk my hand in LN2, one cant do that with 500f oil. The difference is the rate that LN2 goes through evaporation and therefore loses its ability sustain a temperature (by decreasing its density) longer than hot oil, or even hot water. So the comparison of temperatue alone simply doesnt work.

I have been splattered plenty of times with LN2, not a single injury. I have plenty of war wounds from other "safe" kitchen devices and ingredients. In fact we have used LN2 on a hot burn immediately after contact in order to reduce the effects heat can have on skin. A very useful tool indeed.

Not only do my blue gloves absorb LN2 but they have also cracked because the LN2 obliterates the polymer fibers they are made of. Perhaps they arent the best pair, but I did get the most expensive I could find from one of the largest LN2 suppliers. I just find them useless and they make my hands freeze. Everyone in my kitchen will tell you the same.


Edited by inventolux (log)

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Here is something of interest.

Take a smoker and point the smoke into a bath of LN2. Freeze the smoke. There is one more thing that must be added to the frozen smoke to complete the effect. (Because this technique is patent pending for something other than food, I cant say but if you play around with it a bit it will come to you). Place the "frozen smoke" onto a plate and watch it disappear into thin air without any heating element whatsoever.

You can also place oysters into LN2 and seconds later they automatically shuck themselves. That one saves a ton of time.

The liquid encapsulation process from alginates to HPMC and CMC can also be shaved from hours to mere seconds.

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Very cool, everybody. Definitely some inspiration to start working with the stuff. Thanks!

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I just recently got a tank into my kitchen. I see nothing but possibilities with this stuff...I need time to play with it. Heres a few pics from my first experience. I hope you like them.

firsttimewiththeliquid005.jpg

firsttimewiththeliquid006.jpg

firsttimewiththeliquid007.jpg

firsttimewiththeliquid008.jpg

firsttimewiththeliquid009.jpg

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Nice.

Who is your supplier?

I use Praxair. www.praxair.com

Try using styrofoam boxes for holding the LN2. It evaporates much much slower and it wont warp your cutting boards, and possibly make a hole in your steel counter tops.

I like to think of LN2 as the exact opposite of cooking or transferring heat.


Edited by inventolux (log)

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Wow, this thread has really blown me away with some interesting ideas... a few questions arise..

(1) How do the oysters shuck themselves? Do the shells break apart or do they open magically... basically, is the shell lost in the process?

(2) For freezing things that normally dont freeze, how long do they last in that crystalline state? I'm thinking mostly about those pure honey garnishes.

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Of course, the other thing you could do which has some great potential -- though no ideas jump out at me at the moment is "cooking with liquid oxygen".

If you have liquid nitrogen, you can have liquid oxygen anytime you need / want it. Liquid oxygen has a higher boiling temperature than LN2 (liquid nitrogen). This means that oxygen turns liquid at a higher temperature than LN2. So, the liquid nitrogen is capable of literally freezing the oxygen out of the surrounding air. Of course, you don't have enough LN2 to do this typically. However, it does not mean that you can't make it happen on demand.

We used to make a liquid oxygen "still" where we would make our own liquid oxygen. All we did was set up a styrofoam container and run some copper pipe around it it in a vertical coil with the coil coming out the bottom. We'd blow compressed air (slowly) through the copper tube and out the bottom would come air -- along with drops liquid oxygen that we'd catch in another container.

Needless to say, we had lots of fun with it. Probably the best was liquid oxygen plus steel wool plus a match. Molten steel goes flying everywhere. Of course, perhaps molten steel wool does not go well with food but I can see some real potential for charring something on demand. (Putting perhaps a new meaning on Blackened Steak.)

-Art

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Of course, the other thing you could do which has some great potential -- though no ideas jump out at me at the moment is "cooking with liquid oxygen".

Well, I could certainly imagine being able to play around a bit with tableside cooking... if you could work out the liability issues with people getting burnt.

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Wow, this thread has really blown me away with some interesting ideas... a few questions arise..

(1) How do the oysters shuck themselves? Do the shells break apart or do they open magically... basically, is the shell lost in the process?

(2) For freezing things that normally dont freeze, how long do they last in that crystalline state? I'm thinking mostly about those pure honey garnishes.

You put the oysters into the nitro for a certain amount of time (seconds depending on the size of the oyster) and pull them out. The calcium shell doesnt have the ability to expand and contract so the top shell pops off. Once you get the timing down to where you dont actually freeze the oyster meat then you can just go nuts with it.

Belon oysters have never been easier.


Edited by inventolux (log)

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Of course, the other thing you could do which has some great potential -- though no ideas jump out at me at the moment is "cooking with liquid oxygen".

Well, I could certainly imagine being able to play around a bit with tableside cooking... if you could work out the liability issues with people getting burnt.

Liquid nitrogen is indeed used tableside both at El Bulli and The Fat Duck.

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Of course, the other thing you could do which has some great potential -- though no ideas jump out at me at the moment is "cooking with liquid oxygen".

Well, I could certainly imagine being able to play around a bit with tableside cooking... if you could work out the liability issues with people getting burnt.

Liquid nitrogen is indeed used tableside both at El Bulli and The Fat Duck.

I know LN2 is used tableside. I was envisioning *cooking* tableside with LOX.

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This might be interesting to BryanZ and the molecular gang.

I was recently googling mortar and pestle (mostly to figure out which one was which :blink: ) and they had a photo on the Wikipedia page bottom right that showed pulverized plant product using liquid nitrogen to get a powder instead of a paste. I thought it was pretty neat and it would be an interesting way (if one had access to liquid nitrogen) to make fruit dusts and stuff on the cheap.

Anyone else have any ideas for this?

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it can remain powder because the nitrogen dehydrates things as well ...freeze dried

liquid nitrogen can be obtained from a welding supply store like Airgas or Praxair ... but you need a duwer or you could rent one sometimes they will do that at these stores.....or a thermos bottle stainless steel ..they will fill that as well...but that would not be as cheap as a whole duwer


Edited by hummingbirdkiss (log)

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(here's how i remember the answer to your original question:

the pestle is NOT the vessel.

the little rhyme helps me, and if the pestle is not the vessel, it must be--and is--the pounder goodie.)

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Do you mean Dewar?

I could I dont know how to spell it ..the big thing that you keep the liquid nitrogen in that has the dipper to get it out ..whatever that is called ..

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I'm pretty sure Chef Blais has done this quite frequently. He kind of flies under the radar as compared to some of the others but seems to do a lot of interesting things if liquid nitrogen. I personally still have never used the stuff, as I can't get a hold of it.

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Bryan's right about Chef Blais. There's a recent article in the Atlanta paper (here, free registration required) that gives a few details. And if you can make your way through Steven's recount of a very long day, you'll be rewarded with a report from what he calls Ferran Adria's bar mitzvah, where Blais set up temporary shop, producing a number of LN2 dishes.

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How strange to see this topic here because just this morning I ground up lichen samples in lab using liquid nitrogen and a mortar and pestle. The technique is extremely simple once you've got hold of some liquid nitrogen. During the course of the grinding procedure the liquid nitrogen is stored in a columnar hot case (or cold case) though I imagine there would be more efficient ways of storing it. The sample (as little as 100 mg) is placed in the mortar and liquid nitrogen ladled into the mortar. Some of the liquid nitrogen is allowed to boil away so that it doesn't splash out when you try grinding it taking the sample with it. Then you use the pestle to pulverise the sample first with a pounding motion to break the sample into small bits and then with a vigorous grinding motion. The sample becomes brittle like glass and breaks easily. What you're left with is the consistency of fine talc which is completely dry. After that we add liquid to it (in this case alcohol) and it's heated in a water bath.

The whole thing takes all of ten minutes and is really rather fun. Do try it if you get a chance. I love playing with liquid nitrogen. :wub:

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