Jump to content
  • Welcome to the eG Forums, a service of the eGullet Society for Culinary Arts & Letters. The Society is a 501(c)3 not-for-profit organization dedicated to the advancement of the culinary arts. These advertising-free forums are provided free of charge through donations from Society members. Anyone may read the forums, but to post you must create an account.

nathanm

Cooking with Liquid Nitrogen

Recommended Posts

I am wondering if you fill your refrigerator with Nitrogen, how much longer your food would stay fresher.

dcarch

Share this post


Link to post
Share on other sites

OK, I think I get the caution part. I'm utterly terrified, in fact.

So now the question is whether there are things that are cool/interesting enough to try using the stuff. Those of you who have used it at home, what did you do with it?

Share this post


Link to post
Share on other sites

I am wondering if you fill your refrigerator with Nitrogen, how much longer your food would stay fresher.

I think there is a distinct possibility your refigerator might go KAPOW!

Share this post


Link to post
Share on other sites
So now the question is whether there are things that are cool/interesting enough to try using the stuff. Those of you who have used it at home, what did you do with it?
I thought ice creams and sorbets might be the extent of it. I'd like to know what else you could do with it too.

Share this post


Link to post
Share on other sites

"Shaking" drinks. It's also good for enabling quick spherifications and freezing things you can't otherwise really freeze. Come summer, I'd like to try it for some frozen sazeracs and the like, for instance; standard frozen proportions don't work well with classic cocktails (see HERE), but I'm curious as to whether you could cut dilution, subtract heat, and end up with a tasty product.


Edited by Mayur (log)

Share this post


Link to post
Share on other sites

One could certainly have a LN2 cooled freezer, but it would be a serious engineering project and not a DIY job. Dry ice is far more practical.

Re Dewar vs thermos- really two versions of the same thing. Dewar is sturdier, comes vented and is more expensive. Thermos is cheaper and can be made as safe as a Dewar with a drill. I've used a thermos and a Dewar for years. Both work well.

Don't be terrified. It really is safe stuff so long as you don't have it in a sealed container and use your head.

Share this post


Link to post
Share on other sites

Oven gloves and safety glasses.

Share this post


Link to post
Share on other sites
So now the question is whether there are things that are cool/interesting enough to try using the stuff. Those of you who have used it at home, what did you do with it?

In Modernist Cuisine they seem to use it a lot to prevent overcooking meats when deep frying and things like that.

Share this post


Link to post
Share on other sites

------------------- It really is safe stuff so long as you don't have it in a sealed container and use your head.

I don't understand. How do you use your head to store LN?

dcarch :laugh:

Share this post


Link to post
Share on other sites

------------------- It really is safe stuff so long as you don't have it in a sealed container and use your head.

I don't understand. How do you use your head to store LN?

dcarch :laugh:

I could give you a list of people who apparently are doing just that. :laugh:

Share this post


Link to post
Share on other sites

Oven gloves and safety glasses.

I'm going to have to argue with the oven gloves - all my oven gloves are heat resistant cloth. If you spilled liquid nitrogen on them, they would soak it up and hold it to your skin while you scramble to pull them off. It's the same reason I'd sooner work with LN in bare feet than with socks on.

Sealed silicone gloves, on the other hand, would work great.

Share this post


Link to post
Share on other sites

A good thermos alternative is an airpot - the insulated coffee thermoses you see on bad conference buffets. I have this one and it works great. The top doesn't seal, so you get venting without drilling a hole in it, and at 2.5 liters it's bigger than most thermoses. (I picked up this tip from cooking issues). I don't know how long a couple liters will last in an airpot like that, since I've never tried to hold it more than 12 hours or so. In my experience, I lost maybe an inch of the stuff over the course of the day, so it doesn't seem too bad.

As far as safety, I do try to keep in mind that it's a colorless/odorless gas that you won't even notice is suffocating you. I don't get it for parties when we'll have toddlers and pets around, and I do make sure everyone knows what to do (leave the house!) if the container spills.

Share this post


Link to post
Share on other sites

I'm going to have to argue with the oven gloves - all my oven gloves are heat resistant cloth. If you spilled liquid nitrogen on them, they would soak it up and hold it to your skin while you scramble to pull them off. It's the same reason I'd sooner work with LN in bare feet than with socks on.

Sealed silicone gloves, on the other hand, would work great.

Another reason not to use absorbent gloves is because they will absorb the copious condensation that results from LN2 usage. If you've ever used a damp potholder, you know that wet cloth conducts heat much faster than dry cloth.

Share this post


Link to post
Share on other sites

That is interesting. For some reason, I had been under the impression that nitrogen was denser than our atmosphere, but I was wrong...it looks like it's specific gravity is .97 or so, so it's just a little bit lighter than the air around us.

putting some into a bottle of wine is definitely an interesting idea.

Share this post


Link to post
Share on other sites

Edit: Having offered that advice, I have a question of my own for all the other LN2 users out there: A local hardware store carries liquid nitrogen, but specifies that it's not food safe. I think it's cool that they felt the need to specify that, but it made me wonder: how can it not be food safe? Is this something I actually need to worry about, or are they just covering themselves legally?

I've never used LN2 in food applications but I did use it and gaseous N2 in military avionics applications.

Some gases contain petroleum products used to lubricate compressors, inhibit rust in storage bottles, and what-have-you. We purged and pressurized our components with "dry nitrogen", a mix of 95% N2 and 5% O2, that was certified free of oil and other contaminants.

My guess is that the LN2 your hardware store carries wasn't condensed under food safe conditions. Remember, small amounts of contaminants in a gas can be greatly concentrated during liquification, depending upon the process used.

Share this post


Link to post
Share on other sites

I've had frozen drinks made with LN, and the texture is amazing. Literally like pudding with no discernable texture from the ice crystals. Also its cold enough to do this to pure alcohol, so no dilution!

Share this post


Link to post
Share on other sites

OK, I think I get the caution part. I'm utterly terrified, in fact.

So now the question is whether there are things that are cool/interesting enough to try using the stuff. Those of you who have used it at home, what did you do with it?

I poured chocolate into it to make some nest like pieces. Made ice cream with really nice small ice crystals in the kitchen aid - very smooth.

Use dry ice in my panning.

Share this post


Link to post
Share on other sites

In terms of pure novelty factor, frozen honey was very interesting. I froze about a tbsp of it by dropping it into about 1/4 cup of LN, and then broke it up with a fork (and hammer) once it was frozen solid. I ended up with crystals about 1/2 the diameter of a pea that looked like glass. When you bit into one, it would make an amazingly loud squeaky-crunch. It's a little hard to describe, but it shatters in your mouth in an interesting way (right before it melts into honey, of course). It reminds me a little of the way that cornstarch suspended in water behaves both like a viscous liquid and a solid at the same time.

Share this post


Link to post
Share on other sites

I just did some rough calculations of what amount of air 2.5 liters of liquid nitrogen would displace. At 700 X expansion, it would displace 61.8 cubic feet of air. Assuming you're in a sealed room measuring 10 feet by 10 feet by 8 feet, the room holds 800 cubic feet of air ignoring cabinets, people, etc.

That works out to replacing approximately 7.7 percent of the room air. With air being about 21 percent oxygen that would bring the room oxygen level down to around 16 percent.

17% O2 level causes anoxia

10-14% O2 level causes dizziness

6-8% O2 level causes collapse

Less than 3% O2 causes death within 45 seconds

Of course, a spill in a smaller enclosed area such as a car would have much more dire consequences than a spill in an open area as would a spill of a much larger quantity.

As far as protective clothing goes, definitely wear at least safety glasses or goggles if not a full face shield. As mentioned above, absorbent clothing such as oven mitts can be more dangerous than bare skin. We wore Welder's gloves when doing liquid nitrogen and liquid helium transfills. The silicone gloves would work very well in this application.

Share this post


Link to post
Share on other sites

"---The silicone gloves would work very well in this application. "

Can we verify that?

Silicone rubber is about from -55°C to +300°C while still maintaining its useful properties. At LN temperature would silicone become very brittle?

dcarch

Share this post


Link to post
Share on other sites

"---The silicone gloves would work very well in this application. "

Can we verify that?

Silicone rubber is about from -55°C to +300°C while still maintaining its useful properties. At LN temperature would silicone become very brittle?

dcarch

I wasn't thinking in terms of long term immersion in liquid nitrogen. I'd use them more for short exposure and to protect myself from exposure to objects chilled by the nitrogen. I watched an old Iron Chef episode last night where Homaro Cantu was submerging objects with his bare hands.His hands were actually in the liquid nitrogen for brief periods. I wouldn't personally long term immerse either my bare hands or hands covered with any kind of glove. I guess the easy way to answer your question would be to immerse a glove (sans hand)and see what happens.

One other piece of advice regarding gloves/mitts... they should be loose enough to shake off if you need to.

Best bet: Buy a pair of welder's gloves. Worst bet: Use regular cloth oven gloves. Better than nothing: Silicone mitts.

By the way, Cantu didn't wear any protection, so I wouldn't use him as a good safety example.

Hopefully this clears up my thinking at least a little.

Thanks,

Larry

Share this post


Link to post
Share on other sites

"---The silicone gloves would work very well in this application. "

Can we verify that?

Silicone rubber is about from -55°C to +300°C while still maintaining its useful properties. At LN temperature would silicone become very brittle?

dcarch

I haven't re-read the Cooking Issues guide to LN2 in a while, but I think I remember comments about selecting protective gear in part on "what happens if LN2 pours into the cuff." The downside to silicone mitts is that if some quantity gets into the glove, it will be trapped against your skin. This might be even more of an issue with welders' gloves, which have an even wider, shorter "cuff" or "gauntlet." The same issue stands for selecting shoes...

That said, I suspect that using a small quantity of LN2 at home for "novelty" purposes is a lot different than using it day in and day out at a restaurant. At home, you're approaching it with wide-eyed caution and a bit of "beginners mind," where at work, you may get lax.

Another use I've for LN2 is "herb dust" - freezing fresh herbs, then crushing them into a fine powder, which thaws back into a dust of fresh herb flavor. I also recall seeing Cantu and the MOTO guys making "juice balls" working with LN2 bare handed. They put a few tablespoons of juice (beet, in this case) into a normal balloon, filled it with a bit more air, and tied it shut. They then rolled the juice/air filled balloon around on the surface of the LN2. The juice froze on the inside surface of the balloon, freezing into a hollow sphere. They cut the balloon away, leaving the sphere to be plated.

Share this post


Link to post
Share on other sites

I haven't re-read the Cooking Issues guide to LN2 in a while, but I think I remember comments about selecting protective gear in part on "what happens if LN2 pours into the cuff." The downside to silicone mitts is that if some quantity gets into the glove, it will be trapped against your skin. This might be even more of an issue with welders' gloves, which have an even wider, shorter "cuff" or "gauntlet." The same issue stands for selecting shoes...

That's part of the reason for only wearing a glove/mitt that can be shaken off. Welding gloves were standard wear for us while handling cryogens.

As far as thermal hazard is concerned, we work with oil heated to 375 F and don't think too much about it. Given a choice of quickly dunking my hand in LN2 or hot oil, I'd take the LN2 any day.

It's a tool that should be understood and respected, but not feared.

Share this post


Link to post
Share on other sites

I use LN2 at work (science, not food-related). I tend to wear two layers of gloves - rubber on the outside for lack of permeability, thick cloth on the inside for insulation.

Like many have noted, if you do the right thing and treat it with respect, then it's nothing to be afraid of. Having said that, I'd like to emphasize this - please please please please wear safety goggles. If it gets on your skin, the residual heat your skin produces will stop it from burning you right away, and you can usually brush it off without any problems. If it gets in your nice wet eye, your eye will freeze. Immediately. So please, if you do nothing else, wear proper eye protection. I've seen the pictures so you don't have to.

Kudos to everybody who has spoken about air displacement already. We transport it on the back tray of a ute (I think that's a pickup to Americans?) rather than in the cabin.

One more thing - submerge your tools (ladles, tongs etc) into it slowly, rather than dunking them on in, to avoid any violent boiling over. Other than that, have fun!

Share this post


Link to post
Share on other sites

  • Similar Content

    • By boilsover
      Solid intermediate cook, here.  Not especially intimidated by elaborate preps.  But I'm new to SV, and would like a recommendation for a cookbook for guidance and exploration.
       
      I was thinking of Tom Keller's Under Pressure, but I'm wondering if the preps he includes may not be the most generally useful.  What do you all like, and why?
       
      Thanks!
    • By Chris Hennes
      On Nov. 7, 2017, Modernist Bread will finally arrive on my doorstep. Having preordered it literally the first day it was available, to say I'm excited about this book is a bit of an understatement. The team at The Cooking Lab have been gracious enough to give @Dave the Cook and me early electronic access to the book and so I've spent the last week pouring over it. I'm just going to start with a few initial comments here (it's 2600 pages long, so a full review is going to take some time, and require a bunch of baking!). Dave and I would also be happy to answer any questions you've got.
       
      One of the main things I've noticed about this book is a change in tone from the original Modernist Cuisine. It comes across as less "everything you know is wrong" and more "eighty bazillion other bakers have contributed to this knowledge and here's our synthesis of it." I don't think it's an exaggeration to say that Myhrvold and company are now the most experienced bread-bakers in the world. Not necessarily in terms of the number of identical loaves they've produced, but in the shear number of different recipes and techniques they've tried and the care with which they've analyzed the results. These volumes are a distillation of 100,000 years of human breadmaking experience, topped off with a dose of the Modernist ethos of taking what we know to the next level.
       
      The recipes include weight, volume, and baker's percentages, and almost all of them can be made by both a home baker and someone baking in a commercial facility. The home baker might need to compromise on shape (e.g. you can't fit a full-length baguette in most home ovens) but the book provides clear instructions for both the amateur and professional. The recipes are almost entirely concentrated in volumes 4 and 5, with very few in the other volumes (in contrast to Modernist Cuisine, where there were many recipes scattered throughout). I can't wait for the physical volumes to arrive so that I can have multiple volumes open at once, the recipes cross-reference techniques taught earlier quite frequently.
    • By eG Forums Host
      Introduction

      Welcome to the index for the Sous Vide: Recipes, Techniques, & Equipment topic, one of the largest and most influential topics on eG Forums. (The topic has been closed to keep the index stable and reliable; you can find another general SV discussion topic here.) This index is intended to help you navigate the thousands of posts and discussions to make this rich resource more useful and accessible.

      In order to understand sous vide cooking, it's best to clear up some misconceptions and explain some basics. Sous vide cooking involves vacuum-sealing food in a plastic bag and cooking it in a water bath at precise temperatures. Though it translates literally as "under vacuum," "Sous vide" is often taken to mean "under pressure," which is a misnomer; not all SV cooking involves food cooked in conditions that exceed atmospheric pressure. (See below.) In addition, calculations for SV cooking involve not only time and temperature but also thickness. Finally, due to the anaerobic conditions inside the bag and the low temperatures used, food safety issues are paramount.

      You can read the basics of SV cooking and equipment here. In the summer of 2005, Nathan Myhrvold (Society member nathanm) posted this informative, "I'm now going to answer my own initial questions" post, which addresses just about everything up to that point. For what came next, read on -- and be sure to order Nathan Myhrvold's highly anticipated Modernist Cuisine book, due in spring 2011.

      As with all indexes of on-going discussions, this one has limitations. We've done our best to create a user-friendly taxonomy emphasizing the categories that have come up repeatedly. In addition, the science, technology, and recipes changed over time, and opinions varied greatly, so be sure to read updated information whenever possible.

      Therefore, we strongly encourage you to keep these issues in mind when reading the topic, and particularly when considering controversial topics related to food safety, doneness, delta T cooking, and so on. Don't read a first post's definitive claim without reading down the topic, where you'll likely find discussion, if not heated debate or refutation, of that claim. Links go to the first post in a series that may be discontinuous, so be sure to scan a bit more to get the full discussion.

      Recipes were chosen based solely on having a clear set of information, not on merit. Indeed, we've included several stated failures for reference. Where possible, recipes include temperature and time in the link label -- but remember that thickness is also a crucial variable in many SV preparations. (See below for more information on thickness.)

      History, Philosophy & Value of SV/LTLT Cooking

      Over the years, we've talked quite a bit about SV as a concept, starting with this discussion about how SV cooking got started. There have also been several people who asked, Why bother with SV in the first place? (See also this discussion.) What with all the electronics and plastic bags, we asked: Does SV food lack passion? Finally, there have been several discussions about the value of SV cooking in other eG Forums topics, such as the future of SV cooking, No More Sous Vide -- PLEASE!, is SV "real cooking," and what's the appeal of SV?

      Those who embrace SV initially seek ideas about the best applications for their new equipment. Discussions have focused on what a first SV meal should be -- see also this discussion -- and on the items for which SV/LTLT cooking is best suited. There's much more along those lines here, here, and here.

      Vacuums and Pressure in Sous Vide Cooking

      As mentioned above, there has been great confusion about vacuums, pressure, and their role SV cooking. Here is a selection of discussion points on the subject, arranged chronologically; please note that later posts in a given discussion may refute earlier ones:

      Do you need a vacuum for SV cooking, and, if so, why? What exactly is a "vacuum"? Click here, here, and ff. Are items in vacuum-sealed bags "under pressure"? Does a vacuum sealer create a vacuum inside the bag? Do you really need a vacuum, or can you use ZipLoc bags? Also see here, here, and here. If "sous vide" means "under pressure," aren't the items in the bag under pressure? There is more along these lines to be found in this discussion.  

      The Charts

      We've collected the most important of many charts in the SV topic here. Standing above the rest are Nathan Myhrvold's charts for cooking time versus thickness and desired core temperature. We worked with him to create these three reformatted protein tables, for beef, fish, and chicken & pork.

      Nathan provides additional information on his charts here. Information on how to read these charts can be found in this post. For an explanation of "rest time" in Nathan's tables, click here.

      Other Society members helped out as well. Douglas Baldwin references his heating time table for different geometric factors (slab/cylinder/sphere) here; the pdf itself can be found here. pounce created a post with all three tables as neatly formatted images. derekslager created two monospace font charts of Nathan's meat table and his fish table.

      Camano Chef created a cumulative chart with information gathered from other sources including Thomas Keller's Ad Hoc. Douglas Baldwin shared this chart devoted to pasteurizing poultry. PedroG detailed heat loss and steady state energy consumption of sous vide cookers in these charts.

      Finally, there is also an eG Forums topic on cooling rates that may be of interest.

      Acknowledgment & Comments

      This index was built by Chris Amirault, Director, eG Forums. It was reviewed by the eGullet Society volunteer team as well as many Society members. Please send questions or comments to Chris via messenger or email.
       
       
    • By Paul Bacino
      Wonder if someone could get me in the ballpark..the amount of Transglutamase...to make scallop noodles..    %  I mean
       
      ill use a food processor..to purée the scallop..  then inject into a water or broth..to cook?
    • By TomRahav
      Hi,
      I've tried to make the spherical mussels recipe from the Modernist Cuisine books and it didn't work as I expected, so I would appreciate any advice that may help here.
      The recipe calls for calcium gluconate which I couldn't get hold of, so I replaced it with calcium lactate gluconate that I had at home. I used the same ration (2.5%)
      When I tried to create the spheres in the sodium alginate bath I encountered two main problems;
      1. instead of spheres the mixture just stayed as uneven shape on the surface. The bath was 1Kg. water with 5gr. sodium alginate and I let it rest in the fridge for 24 hours before using it so I think the problem is not here. However, the mussels jus mixture (100gr. mussels jus, 0.5gr. xanthin gum and and 2.5gr. calcium lactate gluconate) had a lot of air bubbles in it. Can that be the issue?
      2. In the book the spheres seem to be completely transparent whereas my mussels jus mixture was pretty white and opaque. Is it because I replaced calcium gluconate with calcium lactate gluconate? Or maybe it's because the jus itself should be clarified before it is used?
      Thanks in advance for your support,
      Tom.
  • Recently Browsing   0 members

    No registered users viewing this page.

×