Laser can destory the nutriive content but it is insignificant because of how they use the lasers. Fast frezzing is okay unless it is too fast in which case the cells walls will be destroyed. due to the interior being frozen as well. This depends also depends upon how cold you frezee it and how long. Think about how liquid nitrogen frezees living cells. If the fast frezzing is accompanied by fast thawing it can due major cell damage. If thawing ocurres at a slower rate there is less damage. You can preserve cell tissuses but the extreme change can damage them espically living tissuses. There is a point at which it is too cold to preseve cell tissuses at I believe, but it would be much closer to absolute zero the point at which there is no know molelecular movement at all. Why it turned that pink color I have no idea except that some sort of chemical reaction took place.

I was one of the first celebrities to speak out about the dangers that liquid nitrogen ice cream poses to America's children. Watch your kids!

I passed on your questions about food quality/nutrients to my husband the food scientist (PhD) and he said, "It's hard to say the effects as a general rule - but her two examples are easy to answer. Rapid freezing is always a good thing - freezing preserves nutrients, not destroys them. As an example with vegetables - a quick-frozen vegetable that's 3 months old will likely have a nutrient composition closer to harvest levels than a 5-day old fresh vegetable. And the faster you freeze, the less you destroy tissue structures that could lead to a more rapid loss. As to treatment with lasers, this particular treatment only affects an insignificant fraction of the surface of the food, not to mention never reaching the interior. In fact, that's the whole point of using a laser rather than an oven - you can get targeted heating. Anybody who is concerned about nutrient content of food should instead look at their overall diet rather than the relatively minor differences that these types of treatments might provide (and in the examples given - no actual differences)." So there's the scientist perspective--of course, there are obviously additional issues with how fresh vs. frozen tastes and behaves in cooking that are above and beyond the nutrients. Still, it's useful having a scientist in the household!

Maybe it's juts because I'm vegan, but that KitchenAid looks much more appetizing than the ice cream ... yum, expensive kitchen appliances! :)

For liquid nitrogen, try a welding supply company or an industrial gas supply company. Tell them what you're using it for, and they'll probably loan or rent you the cryoflask to transport it home. Liquid nitro is a blast - I've made ice cream with it about ten times. Well worth the "ooh and ahh" appeal. An alternate way is to have everyone stand around the big metal bowl with a wooden or metal spoon (don't use plastic, it will shatter) and have them stir like crazy when you tip in a little nitrogen. To transport this stuff from the store, you don't need to do much other than either tie it up in the back of your pickup with some bungee cords, or drive home with the windows down. In a cryoflask, it will keep overnight if kept in a cool area. You know how if you drop water on a hot wood stove, it will bounce and sputter and dance around? A drop of liquid nitrogen will do the same thing on the palm of your hand, because the temperature differential between stove/water is as vast as the difference between nitrogen/your skin. My most memorable night with this was buffalo fajitas and liquid nitrogen ice cream. A flask will make GALLONS of ice cream, so be sure you've got plenty of milk on hand and plenty of neighbors to share with. You can also use Bacardi 151 rum as a flavoring - I learned about LN2 ice cream as a way to get freshmen girls drunk off ice cream cones. The alcohol has no choice but to freeze up at that temperature.

What an excellent article. Not sure I'm up to the challenge of cooking with LN yet, but it definitely interests me.

When my hubby and I were in college, we were in a volunteer organization that did hands-on science experiments in inner-city schools and the all-time fave was the "cryogenics" unit where we did tons of stuff w/ liquid nitrogen, including making ice cream for them. Not nearly as yummy looking as what you produced though! :) I have to forward this to my hubby. He'll love it! :)

I don't know about lasers, but supposedly extremely fast freezing is supposed to cause LESS damage to the food than normal freezing, especially delicate fruits like strawberries. The theory is that slowly freezing food creates big ice crystals that puncture and stretch the fruit's flesh. Quickly freezing food creates smaller crystals (like lulu mentioned) which apparently causes much less damage.

Celina, try a local university. The chemistry or biology department should know where to get it. I made this at my local college. It was a blast and tasted pretty good (certainly doesn't beat Ben & Jerry's, but not bad). The ice cream turned a funky pink color (not sure why), but no one got sick so it must have been ok. The only comments I have for people who want to try this is 1) make sure the container you borrow for LN is very clean before you fill it. (they're too expensive to buy just for this). 2) If you're stirring it by hand, it's helpful to wear ski gloves or mittens. Ski goggles aren't a bad idea, either.

Heidi - how cool! Recently on Food TV that guy who does Ham on the Street showed how to use LN2 to make ice cream - his method was a bit different as he didn't actually put it into the ice cream. I can't say that I will try this myself, but it's good to know there are no harmful affects from ingesting it!

I am providing a link to the Material Safety Data Sheet for Liquid Nitrogen. http://www.airproducts.com/NR/rdonlyres/sfgrm072ab4caielohouqxymzia.pdf This stuff can instantantly freeze tissues including fingers, hands, eyes and precautions need to be observed when handling. Liquid Nitrogen has no odor and can displace oxygen causing confusion and nauseau or worse. To give you an idea, if you dip a superball into the material with long metal tongs, then drop the ball onto a hard surface, it will shatter into small fragments--imagine what it would do to your fingers.

That looks super fun! I was thinking of lugging an ice cream maker from home across the pacific, but perhaps all I have to do is find some LN2.

Where do you buy liquid nitrogen? I live in Norway and can't imagine being able to buy it here, but I would LOVE to try out this recipe!! Suggestions?

Sounds like fun!

It was absolutely delicious. We ate it immediately. And as most ice cream aficionados will tell you, immediacy is a key ingredient when striving for a phenomenal ice cream experience. Lulu can tell you exactly what went into the base that night (the version you see in the photos), she had it on the stove by the time I got there. Have fun, be safe! -h

Thanks, Heidi! We're home schoolers working our way through third grade chemistry, and this looks perfect for the kids. I linked to your post at my blog, since I'm sure some of my invisible home schooling friends will be intrigued by the possiblities...

this sounds really cool i'll have to try it

Freezing it so quickly, the fat and the water particles stay very very small - think the opposite of ice milk - giving the ice cream its preternaturally creamy, frozen-cloud texture. That also means that you could use a lower-fat ice cream base like Heidi's above and it would have a creamier texture, more like full-cream ice cream or custard. Full disclosure, though: The recipe in the photos was more along the lines of 1 pint cream, 1 pint milk, and 3 egg yolks.

We did that once! It was marvelous. It's extra creamy, and exciting. Then we spent the rest of the evening playing with the liquid nitrogen, dripping chocolate in until it was frozen on the outside and molten in the middle and eating that, freezing honey and coconut milk and pomegranate molasses, and exploring the safe ways of dipping our fingers in as well.

but heidi - how did it TASTE?