Behold the smooth, sweet powers of liquid N (Liquid nitrogen ice cream! Yum!)

Popular Science ^ | July 2003 | Theodore Gray

[mhking]

Liquid nitrogen is cold. Very cold. So cold that if a drop falls on your hand, it feels like fire. So cold that it can turn a fresh flower into a thousand shards of broken glass. So cold that it can make half a gallon of ice cream in 30 seconds flat.

I first heard about liquid nitrogen ice cream from my friend Tryggvi, an Icelandic chemist working in the Midwest (these things happen). He suggested we make it for dessert at a dinner party I was planning. Yes, he said, he had a recipe, something he'd seen in Chemical and Engineering News.

Now, right off the bat you have to worry about a recipe found in Chemical and Engineering News, the principal trade publication for the sort of people who build oil refineries, shampoo factories and large-scale plants for the fractional distillation of liquefied air (which is where liquid nitrogen comes from). But for the party I was planning, it was perfect: The well-known author Oliver Sacks was coming to visit with my collection of chemical elements; I needed some after-dinner entertainment.

My first concern was whether we would survive the ice cream. That and, if it didn't kill the cook, whether it would be any good. I had visions of hard, crusty stuff that caused frostbite of the throat. It turned out nothing could be further from the truth.

We mixed up a standard ice cream recipe calling for two quarts of cream, sugar, eggs, vanilla and flavoring. (Just about any ice cream recipe and flavor will work.) Then, working in a well-ventilated area (lest the nitrogen displace oxygen from the air) and with due regard for the ability of liquid nitrogen to freeze body parts solid, we gently folded about two liters of nitrogen syrup directly into the cream, much as you would fold in egg whites.

The result, literally 30 seconds later, was a half-gallon of the best ice cream I'd ever tasted. The secret is in the rapid freezing. When cream is frozen by liquid nitrogen at –196°C, the ice crystals that give bad ice cream its grainy texture have no chance to form. Instead you get microcrystalline ice cream that is supremely smooth, creamy and light in texture. Martha Stewart, eat your heart out.

The kids were amused by the clouds of water vapor, though being kids they didn't find anything out of the ordinary in the procedure. They probably think everyone makes ice cream this way. Boy, will they be in for a shock the first time they see it done the old-fashioned way at camp: You want me to do what for a half hour?

A word of caution: Liquid nitrogen can be dangerous in careless hands. Tryggvi and I are both trained chemists, and he actually knows what he's doing. Don't try anything like this unless you do too.

[mhking]

LIKE ICE CREAM FROM TRITON [1] Besides the liquid nitrogen, no special ingredients were used in this experiment. [2] The non-cryogenic ingredients were combined in a mixing bowl. [3] The nitrogen was added a cup at a time. Note the use of heavy cryo gloves—this was not an occasion for oven mitts. [4] The concoction was stirred thoroughly and continuously to keep an unbreakable crust from forming. [5] The ice cream was ready to eat when smooth and free of lumps.

(Bottom right)Theodore Gray is a co-founder of Wolfram Research, Inc., maker of the software program Mathematica. In his spare time he plays with elements at periodictabletable.com.

Photographs by Jeff Sciortino. Styling by Kelly McKaig.

[mhking]

"Hold muh beer 'n watch this!" PING....

If you want on or off this list, please let me know!

[null and void]

A little dab'll Dewar...

[Sokol]

cool...

[Drew68]

Great post! Thanks!

[not_apathetic_anymore]

VERY cool. I'm just geeky enough to want to try this!

[Drango]

Note to self: Do not try when drunk.

[wafflehouse]

cool!

[Ruth A.]

They did a demo of this as a shop that deals in propane and other gases, etc. They used cream, milk and jam. It was so good. Plus, the temperature dropped in the area they were making it.

[supercat]

I wonder if these guys use lox as a barbecue starter?

[HiTech RedNeck]

Only if they want to vaporize the grill.

[Reeses]

To make an excellent low carb ice cream replace the sugar with a Davinci sugar-free syrup. It's sweetened with Splenda which freezes like regular sugar. I recommend. It makes a professional quality ice cream.

[drlevy88]

Pedantic point: it isn't N, it's N2.

I wonder how well pulverized dry ice would work. Not as cold as liquid nitrogen, but much easier to get. Pulverize it in a blender or food processor. (With very, very good ventilation such as a large fan blowing full blast from a window into the kitchen.)

[ffusco]

How about steaks cooked with sodium?

[Billy_bob_bob]

That's the best part. Wait for everything to cool off, then take the remains back to the store and demand a refund. I recommend using the cheapest portable grill or hibachi available. The expressions on the faces of every person working at the store will be worth the price of the LOX.

[RightOnTheLeftCoast]

Smoked salmon is a lousy barbecue starter.

[Paleo Conservative]

The result, literally 30 seconds later, was a half-gallon of the best ice cream I'd ever tasted. The secret is in the rapid freezing. When cream is frozen by liquid nitrogen at –196°C, the ice crystals that give bad ice cream its grainy texture have no chance to form. Instead you get microcrystalline ice cream that is supremely smooth, creamy and light in texture. Martha Stewart, eat your heart out.

But how much does it cost to make ice cream this way?

[supercat]

Only if they want to vaporize the grill.

So don't use a grill--use a pit. BTW, have you seen the photos of the lox barbecue? Pretty darned impressive.

[coloradan]

-196 C is about -320 F, in case anyone is interested.

[drlevy88]

Based on what I googled up with "liquid nitrogen" "price" "liter" this recipe might use $9 worth of the stuff if bought in that small quantity at retail. Not counting the dewar flask (dunno if Thermos bottles would be good enough).

[supercat]

I wonder how well pulverized dry ice would work.

Carbon dioxide would likely add an 'off' flavor.

[drlevy88]

Yeah, maybe a bit acidic. On the other hand that wouldn't be bad for a sherbet.

[prisoner6]

Sadly those pages have been removed by the Net Nannies. The only one left I know of is....

Barbecue

The videos on the old pages WERE REALLY COOL!... Hot acutally.

This ice cream would be the perfect wrap up to a 'Better Living Through Chemistry" picnic.

prisoner6

[drlevy88]

Well it really isn't chemistry. It's physics.

[rmh47]

Many years ago, when I was a technician in a lab that designed and tested air conditioners for a major appliance manufacturer, we used liquid nitrogen for pulling the charge out of units to measure the amount of freon in them.

The stuff was neat to work with. You could plunge your hand into the dewar flask without any problem as long as you pulled it right back out. You could cup your hand as you brought it out and hold a small amount of it in your hand as long as you kept tilting your hand back and forth to keep the liquid nitrogen from sitting in one place.

Apparently, the temperature differential between your body and the liquid nitrogen is so great that the radiant heat from you hand causes the stuff to instantly boil and forms an insulating layer of gas between them.

[Paleo Conservative]

Well it really isn't chemistry. It's physics.

It's Physical chemistry. What would be really cool would be to repeat this experiment at different pressures so a phase diagram could be constructed.

[supercat]

Apparently, the temperature differential between your body and the liquid nitrogen is so great that the radiant heat from you hand causes the stuff to instantly boil and forms an insulating layer of gas between them.

The Leidenfrost effect. If your dip your hand in water, you can then very briefly dip it in molten lead with similar non-effects, but only if the lead is hot enough. Otherwise very bad.

[HiTech RedNeck]

With either the lead or the liquid nitrogen I'd be afraid of splashes.

[Paleo Conservative]

The Leidenfrost effect. If your dip your hand in water, you can then very briefly dip it in molten lead with similar non-effects, but only if the lead is hot enough. Otherwise very bad.

Hopefully the producers of Jackass will not find out about the Leidenfrost effect

[ALS]

Actually a thermos does work, but you have to be veddy careful transporting and it won't last long, so use it quick!

Small chance they'll let you walk out with a thermos full though.

[Boiler Plate]

I wonder if these guys use lox as a barbecue starter?

I saw website from some guys at Purdue doing exactly that. They claim to hold the unofficial World Record in the fastest BBQ lighting category (unlimted class). It was unbelievable, they vaporized the grill in the process.

[Hillarys Gate Cult]

Another use for nitrogen that's well known around aircraft maintenance circles is it's use in vehicle tires instead of compressed air. It stops most all slow leaks.

[RippleFire]

bump

[Paleo Conservative]

It stops most all slow leaks.

Please explain why? Is it because pure nitrogen contains no water vapor?

[ccmay]

Well it really isn't chemistry. It's physics.

Of course it is. All science is either physics or stamp collecting.

-ccm

[Jubal Harshaw]

Not only do you not even need a thermos, but the small size of the thermos might be a problem. I used to make ice cream myself (as per the article above), using a styrofoam cooler of liquid N2 from my lab. The cooler ($3.00 at any grocery store, put one inside another for more insulation) held 2 1/2 gallons, which started to evaporate immediately, but would take hours to completely sublimate off. Of course, I was working in a place that bought N2 by the truckload, so a cooler of N2 was only a few cents.

[nightdriver]

Interesting. I've seen an experimental commercial venture to make ice cream this way. The process was continuous with the ingredients mixed with liquid nitrogen in a high-pressure nozzle and sprayed out into a container.

What landed in the container was ice cream dust - microscopic particles of very well frozen ice cream. It tasted great and had a very unique texture.

[prisoner6]

Oopsies! LOL, Yeah I realized that after I posted...sigh.

prisoner6

[AnalogReigns]

Where does a layman buy liquid nitrogen???

[MHGinTN]

Easy sherbet-like recipe is to use Orange, Rasberry, or even Root Beer soda, with Eagle brand and 1% milk (with organse you can also add mandarin orange pieces, crushed); use a large stainless steel bowl into which you crumble up ~3 to 4 cups of dry ice and immediately place a secomd smaller stainless steel bowl with the mixed liquid in it pushed down into the dry ice; while someone turns the smaller bowl, fold the liquid ingredients using a mixer on lowest speed ... dessert in three minutes, but you have to switch to a large slotted spoon before the dessert hardens completely. I have yet to try it with my wifes countertop mixmaster ... she doesn't yet trust the solidifying mass to not burn out her motor!

[MHGinTN]

Have you tried a Berz-0-matic for lighting the charcoal and getting it quickly to 'cooking white'?

[Jubal Harshaw]

Actually, it's because N2 contains no oxygen. Room air contains ~21% O2. The O2 combines with the rubber in the tires, forming a solid oxidized rubber dust. This process:

(1) reduces the amount of gas available to keep the tire full (since the O2 is no longer a gas)

(2) causes the tire to fail.

N2 doesn't react with rubber (or with anything else, for that matter, under the conditions found inside a tire), so it stays in gas form, and the tires last longer.

Water vapor is also theoretically bad for the inside of tires, since it allows microorganisms to grow in the tire, but vulcanized rubber is apparently toxic enough to the little buggers that this is generally not a problem.

[HiTech RedNeck]

I've never heard of tires being found full of oxidized rubber powder. It would seem to me that if this truly is a problem, some kind of coating on the inside of the tire would work just as well.

[Jubal Harshaw]

Whoops. I forgot about the effect of water + O2 on the metal parts of the tire. Water + O2 rusts the steel belts and valve parts of the tire. Yet another way in which N2 (no H2O or O2) improves the life of the tire.

[JerseyHighlander]

Do either of you have the Purdue University professor's LOX barbeque explosion video? I've been looking for it since it was first posted on FR, just days before the university made the professor remove the video from his website.

[Jubal Harshaw]

(1) The oxidized rubber does not fall into the inside of the tire; it's generally still in the tire matrix, but without the structural properties that helped keep the tire together before the rubber was oxidized. Perhaps I should not have used the word "dust" in this context; I was simply trying to provide a visualization of how the rubber fails after being oxidized. Your question illuminated the fact that I did a bad job. So, please forget the word "dust;" try "non-structurally stable rubber" instead.

(2) Tires do have inner liners, as well as antioxidants within the tires material itself. These are both subject to oxidation, and eventually wear out.

[mvpel]

You mean Dippin' Dots?

[Old Professer]

LOX? You mean LOX? Not lox?

Damn, no wonder I have such a messy, oily, stinky grill!

Now, what do I do with all these bagels.

[Old Professer]

When the history of the world is finally written it will be revealed that it was oxygen that reduced it all to dust.

[nightdriver]

"You mean Dippin' Dots?"

Most likely the same process, however what I saw twenty years before this guy patented "Dots" was a lot finer grained.

Back in the sixties they were looking for markets for liquid nitrogen as the demand for it is not nearly as great as it is for oxygen and they produce almost four times as much of it to get oxygen out of atmospheric air.

This ice cream process was just one of the suggestions.