Making Ice Cream With Heavy Metal

After his last project left him with an eleven-pound block of aluminum, [Jason] got to thinking of what most of us would in that situation: fresh made ice cream. His mind was on the frozen concoctions of the aptly named Cold Stone Creamery, a mall food court staple where a chilled stone is used to turn fresh ingredients into made to order sundaes.

[Jason] did the math and found that an eleven-pound chunk of aluminum can absorb a little over 67,000 joules, which is over twice the energy required to freeze 100 g of water. In place of water he would be using cream, condensed milk, and strawberries, but believed there was a large enough safety factor to account for the differences between his ingredients and pure water.

His first attempt didn’t go exactly as planned, but with his Flir One he was able to back up his theoretical numbers with some real-world data. He found that he needed to start the aluminum block at a lower temperature before adding his ingredients, and through experimentation determined the block only had enough energy to freeze 30 g of liquid.

In the end [Jason] was satisfied with the frozen treat he managed to make from the leftovers of his radial mill project, but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.

Of course, if putting food on a slab of metal from your workshop doesn’t sound too appealing, you could always go the NASA route and freeze dry it. Either method will probably make less of a mess than trying to print objects with it.

25 thoughts on “Making Ice Cream With Heavy Metal

  1. Nice, I love getting one of these made whenever I make it to mainland europe.

    It’s worth mentioning however that NASA never freeze dried ice cream for space. It’s too crumbly, a huge no-no, for space stuff.

    They just sent up actual icecream if needed. It honestly works better than having crumbles everywhere and can even be eaten from the tub!

    People seem to hate astronaught ice cream for it’s chalky taste (I’ve never noticed, I think it’s delicious) so by some accounts it wouldn’t even be an appropriate replacement.

    Check it out for yourself https://youtu.be/3w9ho2fPG0w?t=29

  2. “…only had enough energy to freeze 30 g of liquid.” Wouldn’t that be “anti-energy” or “non-energy”? ^_^

    But Cold Stone Creamery do have awesome stuff… Back in the days when I lived in Dubai we used to hit one of their places a few times a week. No wonder I gained 15 kilos (33lbs) during my years there. :-(

    1. heat capacity sees more appropriate. you put that block in the freezer and all the heat gets sucked out of it. take it out and it starts to soak up the ambient heat (you should probibly insulate it to keep from sucking up heat from things you dont want cooled) and that of the creme. it can only absorb so much heat before equilibrium is met and no further freezing of the creme would occur. this equilibrium point needs to be below the freezing point of the creme if you want it iced. you are really just moving heat around.

  3. So, the poster found out that you can’t just assume that the entire heat capacity of a mass will occur at the surface. Heat transfer and thermodynamics are supposed to work together, not fight one another.

    “…but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.”

    Hmmm…and it would probably be even better if you could spin the mix with some paddles to mix in air (called “overage” in the industry) so that it tastes as it should. And you should keep the brine out, so a bucket is in order…

    1. White mountain ice cream maker! Love it! Inherited a 50+ jear old one from my uncle and its still going strong. They make a hand cranked version as well iirc. Glad I have the motorized one, though…

  4. Steel would need only 2/3rds the volume (although almost twice the mass), and thus massively lower costs should its lower conductivity be acceptable. An even better pick is Parafin wax, its solid at room temperature and would only need ~36% the mass and similar volume to aluminum. Or if your willing to use a toxic fluid in a sealed pressure tank liquid ammonia would require only 2/3rds the volume while being less than one fifth of the mass! But probably wax is the go…its affordable to get a couple of kilos of as well…

  5. I think the only reason metal was ever used is because it was available for free. By weight metals have very, very low heat capacities. If you really want to repeat this I’d ask a kitchen contractor if you could buy a scrap of cracked granite off of them. That should have better capacity. Also I’m pretty sure Cold Stone starts with frozen, or near frozen, ice cream and just uses the stone to keep it from melting while ingredients are mixed in.

    1. Metals have nice thermal conductivity though, a few channels to run a cold liquid through might do a good job. And some sort of bowl arrangement to put the cream into. Maybe a shitload, a complete ton, of peltiers would be nice, but probably a load of dry ice would be better. Or liquid nitrogen.

  6. If you circulate a coolant through the aluminum block and then have a “cold reservoir” (aka a bucket of ice) elsewhere with the coolant running through that, you can pull this off…. But why? What might be a “cooler” project is having a peddle driven refrigeration cycle, so that you could peddle yourself some ice cream…. Get it? Cooler?… I’ll show myself out…

  7. Okay, I know it’s just a title pun and it’s *fine*…

    But unlike most metals, aluminium isn’t a heavy metal. It’s a light metal. Of elemental metals, only magnesium is less dense.

      1. Oh, you’re correct. Lithium and beryllium are less dense. I don’t know what I was thinking.

        Lithium is highly reactive and beryllium is toxic so yes, you’re also right they’d be poor for making icecream with :)

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