Milling ice molds for craft cocktails

Want some fancy ice for your next cocktail party? You can try to find spherical ice-cube trays but you won’t get the kind of results seen here. It turns out the trick to this isn’t how you freeze the water, it’s how you melt the ice.

[Brendan O’Connor] started this project after seeing an ice mold that could make beautiful shapes rather than just cubes. But the price tag was $1400. If he could make his own at a hackerspace we’d bet that would pay his membership for an entire year!

The concept is pretty simple. The video after the break shows the mold he was trying to recreate. It’s two hunks of metal with a shape milled into them. The mold is pre-heated, then an oversized hunk of ice is placed between the blocks. The heat melts away the parts you don’t want, and leaves a perfectly shaped ice orb in between. Gravity is responsible for pulling the mold halves together as they slide along some machined rods.

With a big hunk of scrap aluminum he milled two halves of a sphere. They can be sufficiently heated if held under running water, and a some leftover printer rails keep the two parts aligned as the ice orb is formed. Now [Brendan] just needs to work on his method of creating a crystal-clear ice block as a starter and he’ll have achieved total win.

[via Sector67]

25 thoughts on “Milling ice molds for craft cocktails

  1. Insulate the guide pins and set up a contact alarm for when it’s complete to prevent over-freezing without requiring constant watching. Nice.

    1. Also mill in cooling channels and setup a chiller circuit to turn on when the switch is activated so you could walk away from it and it would not melt.

      Also somehow involve an arduino in this.

    1. You also need to start with pure DI water *AND* constantly agitate the water while it is freezing with a small pump. That’s the trick to clear ice.

    2. +1 When you boil water, all the gas mixed in the water can’t stay in that form due to change in temperature and leaves in bubble form.

      Once the water is boiled, pour in a pan and just put it in the freezer. I always used to make clear ice before parties using this method.

  2. If you counter-rotate the mold halves and ‘grind’ the ice, you’ll likely get faster results. I’ve read that you can do the same with stone.. ;)

  3. I’m sure I saw somewhere (possibly Mythbusters or some other show like it) that if you agitate the water while freezing it then all the impurites sink and the bulk freezes clear.

      1. I can’t speak for what was on the “How it’s Made” episode but what people are talking about was on mythbusters.

        Specifically, the episode where they were trying to make lenses out of ice in order to see if they could start a fire with an ice lens.

  4. I think the how you get the cloudiness out of the ice is by having it flowing while freezing. This should make it freeze from the bottom up and not the outside in.
    Good Luck!

  5. “To prevent melting, you should have the maximum volume (making things cold) with the minimum surface area (melting).”

    this is not true !

  6. for clear ice, you can agitate the top surface of the ice so that it does not melt. better is to have a constant flow of water across the top. You don’t need DI water for clear ice if you have a constant flow of water across the top surface.

    1. Seams are the problem with that, as well as cracks in the resultant ice (reforming the ball’s outer surface prevents it from shattering like a normal ice cube does when you put it in a drink).

  7. Use peltiers!? Hot then when done switch to cold. Also, for clear ice industrial machines freeze it in layers (with a waterfall), the agitation facilitates this but doesn’t directly make the clear ice.

  8. As I recall on one of those shows (How It’s Made or Mythbusters), they froze ice blocks for ice sculptures from the sides, forcing the impurities to the center of the ice block. Then they drilled out the impure ice core and filled that with fresh water. After freezing this, it ended up very clear and ready to use in an ice sculpture.

  9. Maker’s Mark sent me an ice tray that makes 6 spheres (“Bourbon Balls”) at a time for xmas last year. It works very well, and completely free!

    (sign up for their Ambassador list, they always send neat things for your birthday and holidays, sorry for the plug)

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