Freeze Drying Astronaut Ice Cream

In our younger and more vulnerable years nothing was greater than visiting a museum, going to the gift shop, and badgering our parents to buy a pack of astronaut ice cream. Freeze dried ice cream leaves a taste of nostalgic chalky sweetness in our mouths, so we’re very excited to see that [Ben Krasnow] is now making his own astronaut ice cream.

The basic principle of freeze drying is simple. All you have to do is reduce the pressure and temperature of the food below the triple point of water and pump the sublimated water vapor out. For [Ben], this meant he needed to cool his Neapolitan Klondike bar to -30° C in a bath of chilled ethanol and pump out the air with a vacuum pump.

Interestingly, [Ben] found it necessary to heat his ice cream while under vacuum to extract more water vapor. This makes sense; at the pressures he was dealing with, [Ben] would never come across water in a liquid state. The entire process took about 18 hours. [Ben] admits this may have been a little longer than necessary, but it’s a small price to pay for reliving childhood memories.

29 thoughts on “Freeze Drying Astronaut Ice Cream

  1. I actually picked up a pouch full of this stuff at Fry’s the other day. (They had it in a huge bin) It doesn’t taste bad. Although, doesn’t feel like ice cream, because its not cold.

    Interesting article though.

  2. Looking over the parts he used, I believe this could be the most inexpensive DIY freeze drying build I have ever seen. The pump he uses is only $175, which for a pump that can get down to 3 pascal is insane. Then he has a $15 vacuum gauge, some old lab glass, copper fittings, and some ribbed hoses for the vacuum line. Probably would cost just over $200 to build with new parts.

  3. I’ve done this, except with a $5000 vacuum pump. I used dry ice to freeze the ice cream instead, I imagine if you live a bit further north you could just leave the ice cream outside instead – the critical part is freezing it as fast as possible, if you’re working with non-frozen food.

    You’re not evaporating water, you’re sublimating ice. Heating it is necessary to get the movement needed around the p-t graph.

  4. The only thing I’d like to see someone improve on is the cold trap. A proper DIY cold trap would be cool to see done, since cold traps are not terribly complex yet insanely expensive.

    As for freezing food as quickly as possible- my tips would be to cut the food up into small pieces and spread it outside on a metal baking sheet during a Minnesota winter. -10 F will freeze those things very quickly. But a cooler of dry ice and alcohol will also do the trick nicely. You’d need the dry ice for the cold trap anyway.

    1. Probably not food safe, but keep in mind that the vacuum pump is isolated from the food by the cold trap, so the real question becomes “How food safe is your drying vessel?”

  5. I’ve always been tempted to try this with the lyophilizer in our lab. It goes down to a few tens of millitorr, and can automatically heat the drying surface when necessary. I just don’t know how the higher ups would respond to finding ice cream in a piece of equipment costing tens of thousands of dollars. Also, 18 hr isn’t bad for an ice-cream sandwich. Our products (maybe 25ml all total) can take 12 hours or so.

  6. This puts a whole new use to this 200 liter explosion-protected vacuum drying oven we are getting in our lab by next week. I would also like to make beef jerky in it…
    I’m a naughty, naughty laboratory assistant and also a lousy safety inspector ;)

  7. I lived a deprived childhood. ;) I never had a chance to badger my parents to buy use astronaut ice cream, not that it would have gotten me anywhere. Not sure how he manages to do so, but another interesting video from Ben, thanks Ben.

    1. You’re not missing much. It has about the same texture as the mini marshmallows in Lucky Charms. It’s just a bigger block of the stuff.

      Still, it’s pretty good stuff for what it is.

  8. The freeze dried “astronaut” ice cream is a myth. It was created by a space novelties company and the only time it ever flew in space was as a memento for one astronaut just so he could say that he was the only one to actually have it in space.

    On occasion real ice cream has been eaten in space – when there’s an empty freezer during launch (which will be filled with samples for the ride home) it can be filled with frozen treats for the crew. The STS-74 shuttle mission flew many frozen Dove bars to the Mir space station (minus the ones consumed by the shuttle crew for “quality control” of course).

    One mission tested a mechanical fridge and the results were freshly made gelatin desert.

    Sometimes astronauts have created their own frozen treats. Get permission to use a science freezer and put in a container of applesauce overnight.

    If you want a real genuine authentic astronaut Thanksgiving or Christmas dinner you can buy it in your own grocery store – it’s an ordinary $3 Dinty Moore turkey dinner.

    And Tang was never the “drink of the astronauts” – any instant powdered drink can be flown.

  9. Now that you have the equipment, the next thing to try is freeze-dried shrimp. Use small shrimp, straight out of the water. You don’t need to add salt. Serve in a bowl at your next party.

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