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How to Make the Death Star Ice Mold Turn Out Clear

Update: Learn more about this in The Ice Book, out May 2023!


Did you receive one of those cool Star Wars Death Star ice molds as a gift (or buy one for yourself), only to have it come out looking not like the advertisement:

Screen Shot 2016-12-24 at 9.47.27 AM
Image from the ad on Amazon.

But more like this?



Yeah, more like post-Skywalker Death Star. 

Don't worry, I have a fix for you. The trick is take advantage of Directional Freezing, a technique I pioneered here on Alcademics.com. 

In a nutshell, the regular way ice ball will freeze is from the outside-in. The ice "wants" to be clear in a nice neat organized lattice so it pushes trapped air into the center of the ball, where it appears cloudy and also cracks as it expands. With Directional Freezing, we make sure the ice ball freezes from the top to the bottom, pushing that trapped air out the hole in the bottom. 



We accomplish this by using a Thermos Funtainer (or other similar insulated mug, but this one fits the 2.5" ice ball molds perfectly and takes up the least amount of space in your freezer). 

  1. Fill the Thermos with water
  2. Fill the Death Star ice ball mold with water (I use water from a Britta filter)
  3. Hold your thumb over the hole in the Star Wars ice ball mold and turn it upside down, setting it on the Thermos with the hole facing into the thermos. 
  4. Put it in the freezer and wait 12 20 hours or so for it to freeze, depending on your freezer. 

The ball should now be super clear. 

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Common issues are that it comes out more egg-shaped or that it's a touch cloudy on the last part to freeze (where the hole is). If you're experiencing that, try:

  • Move it so that the hole is either directly down in the center of the thermos, or a little on an angle towards one side (depending on if your freezer is excessively cold or warm)
  • Beware excessive vibration/jostling the container in your freezer, usually caused by opening and closing the door a lot. This can cause bubbles and stop the directional freezing process. 
  • Some super-obsessed Alcademics readers claim that to get every last cloudy bit out of the ice ball (often the last part to freeze is slightly 'frosty' in appearance), use bottled water. We haven't figured out why this would make any difference, but they claim it does. 
  • Most sink faucets have a aerator on them - even if your water doesn't need to be filtered, letting it sit a while or removing the aerator can help if the ice is still cloudy and freezes fast. 

Enjoy your super clear Star Wars Death Star ice balls, and may the force of Directional Freezing be with you.


To see all the many, many ice experiments on Alcademics, follow this link to the Index of Ice Experiments



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Pawel Babiak

As usual, great stuff. Thank you, Camper.


Hey Camper, the cloudy water after the ice melts can be solved by using distilled water.


Wouldn't this break the thermos?

Camper English

It can, certainly if you use a glass-lined thermos. But I've not had this model break after many uses. It's of course best to stop it after the ice ball freezes but before most of the thermos does.

Nich Box

Maybe worth trying with this...
Black (natural color) mineral water. Seems like it would be a perfect fit!

Camper English

Typically if there is anything in the water (color, flavor, minerals) it bunches up in the middle/bottom with the trapped air, that said, if I see this product I'm totally going to try it.

Bruce Harlick

Thanks! I just had this ice mold linked to me (and I already have one) but haven't gotten great results with getting clear ice balls out of it. I'll give this method a try.

Alicia K

I may or may not have about 30 death star ice molds. And I also may or may not have purchased about 4 funtainers (3 batman, 1 minion). Cue: "THIS GIRL IS ON FIRE...."

Camper English



What should I do if the sides leak a bit. Is there anything I can use to seal it better?

Camper English

The sides of the death star mold leak? Sounds like you got a bad one - it should stay sealed.

Joe McPherson

GeekDrink now has them for $9.99. https://geekdrink.store/products/creative-silicone-blue-wars-death-star-round-ball-ice-cube-mold-desert-sphere-mould-diy-bar-party-cocktail


I must have bought 4 bad ones. All of mine leak. It's so annoying and end up with only half a death star and a whole lot of ice soead out in my freezer. Please help.

Greg Gioia

I don't want Death Star ice cubes. Do you think this mold


will work with that Thermos?

Camper English

I think those lips near the hole could be problematic. I use these ones and they definitely work great: https://amzn.to/2PFvP12


Pharmacist suggested using water that's been thru reverse osmosis. It's either Desani or Aquafina. Check label.


Does it have to be a thermos? Can I use a glass bowl or cup that fits the mold?

Camper English

It should be insulated, and you'd want to avoid glass in any case as it can shatter when the water freezes.


I have a silicone ice ball mold that is two x two —(https://www.amazon.com/dp/B07W8DHRL5/ref=cm_sw_r_sms_api_glt_fabc_YJABASYHA527BDYBX8C2) — Any suggestions for how to accomplish directional freezing?

Also, how do you keep the mold from leaking between the time you take your thumb off the fill hole, and the time you get it placed in the water, inside the thermos?

Thanks for the great site, and comments—I’ve learned a lot.

Camper English

@Gordian-Knot - If it fits on top of any container and the holes are submerged into the water it *could* work. You could try it on some kind of tupperware/disposable pan as long as you can keep it partially out of the water in the container beneath.

Alternately, you could probably use four thermoses. For now you could try with one thermos and just balance the rest over the edge on a stack of frozen peas or something.

Because water expands when it freezes, the little bit of water that comes out when you tip it over doesn't make a difference, the mold is still full.


How does the top exposed bit freeze clearly if it’s not insulated?

Camper English

@John - The first part of water to freeze is clear, the last part is cloudy.

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