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Making Clear Ice Balls with Tovolo Sphere Ice Molds and a Cooler

We already know that you can make perfectly clear ice balls using a round silicone ice mold and an insulated mug.

(Read about all the ice experiments on Alcademics by following the link to the index.)

Now Alcademics reader Jason F. has refined the process using larger Tovolo Sphere Ice Molds and a cooler.

Clear ice ball alcademics dot com

The equipment is specifically the:

Cooler and ice sphere molds

If you're new to the ice experiments on Alcademics, it might help to read the top stories linked to from the Index of Ice Experiments on Alcademics

This ice ball process is similar to the method using the insulated mugs and making ice blocks/cubes in a cooler:

  • You fill the ice ball molds with water, and float it hole-facing-down in water in the cooler.
  • As the water freezes from the top-down (due to the insulated cooler), it pushes any trapped air and impurities toward the bottom of the cooler, leaving only clear ice in the mold. 


Fill the cooler almost full with hot tap water. Allow it to cool for a few hours until it is about body temperature. Separate the molds put them in the water and re-assemble them under water making sure that all of the air is out of them.

Grasp the top and bottom of the mold keeping one finger over the drain hole of the mold. Take it out of the water and dump the water remaining in the white plastic part of the mold.

Wet ice molds


Place the mold back in the water, hole side down and release your finger from the drain hole on the rubber side of the mold. This will ensure that air has not gotten in and give the top some buoyancy.

Place the cooler in the freezer for 48 hours. The ice will form at about 1 inch per 12 hours. The block will not freeze all the way through and that is exactly how you want it!

When you remove your cooler it will look like this:

Frozen ice molds

Chip away the surrounding ice using the ice pick. Reserve the ice as you will have some nice, clear rocks for other cocktails.

Chipping away ice

You will get a block out with the molds frozen in it. Work on the shammy or tea towel so it does not slip around.

Ice molds in block

Remove the sphere from the molds, they will just pop out no need for running water over them.

Tempering The Ice 

Allow the spheres to temper (sit out) on the towel for about 10 minutes. Tempering them is an important step so that they don’t crack when liquid is poured over them.

You can store them in the freezer but remember to temper them when you remove them.

When they come out of the mold or freezer they will be dull on the outside. You know they are tempered when they are clear all around.

Clear ice ball alcademics dot com

Thanks much to reader Jason F. for the method, the text, and the pictures! 

The index of all ice experiments on Alcademics is here



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David Schofield

Thanks for sharing these details from Jason.F, very useful…if only we could produce more and quicker, guess there's no pleasing some people.
Regards, David.


I used to be all about these DIY methods, but recently I just went ahead and bought a Wintersmiths. Sadly, I just no longer have the time (nor the freezer space) to do these cool DIY methods.


Also, thanks for the tip on tempering!

Lee Morgan

Why use hot water?

Camper English

I left that in from Jason F.'s instructions. I don't use hot water normally. Dave Arnold also mentioned using hot water but I don't recall why.

In my experiments hot water didn't make any difference.


You can use the Tovolo sphere molds for the insulated mug method. Just take a scissor and trim off the two tabs on the top to make it fit into your mug. The tabs are non-functional. Works good.

Camper English

Hah! Thanks for the hack.


In case of trapped gases, I believe. (See my comment on the first directional freezing thread -- I think what I said about boiling water should also apply to hot water to a lesser degree.)

Camper English

Yeah I really need to do the same volume of boiled vs unboiled water experiment to see if the ice is any clearer.

kyle ahmad

Would the bottom half of the mold be able to withstand the pressure of the frozen ice?

Camper English

Yes it does both because it's flexible and because the ice is freezing from the top-down so that the pressure is pushing stuff more towards the bottom of the cooler than into the mold. I've not had problems with any ice molds breaking (nor the igloo cooler, which I've frozen probably 100 times).

kyle ahmad

i see. didn't think of it that way. just got mine today and can't wait to try them out at the bar i'm working at.

cheers mate!

Alex sc

Hi there :)

What is the best way to storage this awesome Ball, do they stay this cool in a "Topper" in the frezzer? Or do they get damaged?

Camper English

I'm not sure what a Topper is, but once you have nice ice you can store it in plastic wrap, plastic bag, or plastic container. This keeps it from sublimating and also keeps any refrigerator smells out of the ice.


Do you Recommend this method over the funatainer/thermos method?

Camper English

Hi - The Funtainer method takes up less space and is easy to get out of the mold, so I prefer it.

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