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Liquid Nitrogen

j
Jansenqwer Jul 3, 2012 08:18 PM

I'm planning on making some alcoholic sorbets, in need of liquid nitrogen. Anyone know where in the DC area I can get a hold of some? Thanks in advance!

  1. m
    MikeR Jul 4, 2012 08:20 AM

    Robert's Oxygen in Merrifield (VA) might be able to help you. Or Potomac Oxygen in Alexandria. Look up "welding supplies" in the Yellow Pages if you're in a different part of town.

    1. s
      shake N baik Jul 5, 2012 06:55 AM

      I've noticed Heston Blumenthal use dry ice as an alternative to liquid nitrogen. Easier to obtain, maintain, and safer too.

      6 Replies
      1. re: shake N baik
        h
        hotel Jul 5, 2012 11:57 AM

        As a chemist, let me say that dry ice would definitely be the better choice if you want to make sorbet. You'd need a ton of liquid N2 (boiling point -200 C) since it quickly boils at room temperature. Dry ice has a standing temperature of about -78 C and a bottle of 80 proof liquor will freeze at around -30 C. You should definitely still wear some sort of working glove while handling the dry ice.

        1. re: hotel
          h
          Hue Jul 5, 2012 03:11 PM

          Help me out here Mr Hotel ..is it even possible to but liquid nitrogen "over the counter".
          That's some pretty nasty stuff to be messing around with, even dry ice can get a little iffy.
          In Maryland one has to be at least 21 to buy dry ice.

          1. re: Hue
            h
            hotel Jul 6, 2012 12:21 PM

            You'd be hard pressed to buy liquid N2 anywhere "as a civilian." Even if AirGas would sell it to you, there would be an exorbitant deposit on the tank, and I'm fairly sure the smallest size you could get is 200 L. That cylinder is about 5 ft tall, 3 feet wide, and weighs approximately 300 lbs. If they would disperse a few litres (doubtful) into a synthetic grade dewar for you, you'd still have to buy the dewar. In that case you'd need at least 10 L to account for loss during pouring and transit, and the dewars are probably around 700 dollars.

            If you know someone in a chemistry or biology lab - they can probably pirate you out a few litres.

            It's not all that bad to be around - N2 makes up 78% of our atmosphere. When it's compressed into liquid it's just very cold. Like any and all chemicals (or anything dangerous for that matter) if you exercise caution when using it, it won't hurt you. I've splashed it onto my arms before and it just tingles a little bit. I wouldn't recommend you go dipping your fingers into it though, a few seconds of constant exposure will definitely cause frostbite - or worse.

            Dr. Hotel

            1. re: Hue
              a
              Alan408 Jul 8, 2012 10:17 AM

              Liquid Nitrogen is available "over the counter". Comes in many sizes, e.g., nitrogen for topping off a bottle of wine, many car tire installers use nitrogen. A half gallon size bottle is ~$50. A small scuba tank size maybe $125. Gas is inexpensive, the tank costs.

              1. re: Alan408
                v
                Virginian Jul 9, 2012 10:18 AM

                Those applications do not use liquid nitrogen. They are uses of gaseous nitrogen. Big difference.

                1. re: Virginian
                  a
                  Alan408 Jul 10, 2012 07:52 AM

                  Thanks

        2. o
          onocoffee Jul 8, 2012 09:07 AM

          As Shake said, dry ice is a good alternative to liquid nitrogen. It's readily available and easier to handle.

          Proper storage and transportation of liquid nitrogen requires specialized tanks or smaller dewars. Don't know if places like Robert's Oxygen will rent you one and they're not cheap to buy - though some deals can be found on eBay.

          A possible alternative is that you might find a supply house or individual who will allow you to port away the liquid nitrogen in a styrofoam cooler (think of those cheap 7-11 breakable foam jobs). Unlikely, but if you can find someone who will sell it to you that way, you might be able to get it done cheaply.

          Caution should be heeded when working with liquid nitrogen. First off, it's extremely cold and can cause bodily damage. Be careful when working around it and be sure to wear pants and closed toe leather shoes. Why? because if you're wearing canvas/fabric shoes and you spill the liquid nitrogen on your feet, you might lose your toes.

          Also, be sure to work with the nitrogen in a well-ventilated area. Unlike CO2 gas that is hard to breathe and you have a definite sense of shortness of breath to alert you that your suffocating, nitrogen gas does not work the same way. It does not react with the lungs in the way CO2 does - meaning that you'll keep breathing nitrogen in the manner that you normally breathe until you asphyxiate yourself and drop dead.

          2 Replies
          1. re: onocoffee
            h
            hotel Jul 9, 2012 08:31 AM

            That's just not true about the asphyxiation. First of all, no gas "reacts" in the lungs. Your lungs act as an area where your blood picks up oxygen or carbon dioxide. Yes there is a binding of O2 or CO2 to the heme Fe, but it's not really a reaction. Second, hemoglobin does not bind nitrogen at all so you'll breathe it in and directly out. Finally, 78% of the air is comprised of nitrogen, you couldn't drastically displace the amount of oxygen in a room with nitrogen to cause a problem.

            You could cause frostbite if you're not careful, but again it's not going to happen from a brief splash.

            1. re: hotel
              o
              onocoffee Jul 11, 2012 02:13 AM

              hotel- you're probably right. The reports that I was reading a couple of years ago were discussing containment issues of larger liquid nitrogen tanks and the use of nitrogen sensors, along with the warning that if nitrogen were released in the workspace and a co-worker was unconscious on the floor to leave them because they would already be dead.

              But I agree, a small dewar of liquid nitrogen probably doesn't pose the same threat.

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