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Percent Cloudiness in Top Frozen Block Ice

I'm somewhere along the process of creating an ice cube tray that takes advantage of the top frozen ice that I make in an Igloo cooler. As the cooler lid is off when I freeze water in it, the water freezes from the top down like a pond in winter. The cloudy part of the ice (where air an impurities migrate as the water freezes) are only in the bottom of the block.  

In the below picture the block has been turned upside-down after removing it from the cooler. 

Top view not all super cloudys
 Most of the time when making ice for myself at home, I leave the cooler in my freezer for a couple of days then dump out the ice before the bottom portion starts to freeze and get cloudy- that way the entire block of ice is clear and I don't have to cut any of it off.

In a recent set of experiments, I wanted to see what percent of the block of ice was cloudy if I let the block freeze entirely. So far I've done three measurements. 

Three out of six partial cloudy one inch totess
As you can sorta see, a portion of the ice has bubbly streaks in it but is mostly clear, then there is an all-cloudy last bit. 

Trial One:

Total height = 3.75 inches
Somewhat cloudy  =  last two inches
Very cloudy, unusable = last 1/2 inch
Percent unusable cloudiness = 13%

Trial Two:

Total height = 6 inches
Somewhat cloudy  =  last three inches
Very cloudy, unusable = last 1 inch
Percent unusable cloudiness = 17%

Trial One:

Total height = 6 inches
Somewhat cloudy  =  last two inches
Very cloudy, unusable = last 1 1/2 inch
Percent unusable cloudiness = 25%

So we're looking at an average of 18% of the ice is too cloudy to use in a cooler of this shape and size. 

Why might this information matter? If I develop an ice cube tray that fit into this cooler I would want to be able to remove the last cloudy bit so that it wouldn't get into the ice. I wanted to know about how much waste we're looking at. 

But one thing I'm learning with repeated experiments is that by freezing from the top down the water expands and puts a lot of pressure on the bottom of the cooler. (Think of how a plastic bottle will bulge when put in the freezer.) With repeated experiments that cooler is starting to warp on the bottom, plumping out in the center. A better freezing vessel would be flexible on the bottom. 

To see all of my ice experiments use this link.


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Mr Manhattan

I think your next purchase needs to be a electric chain saw.

drink maestro

I think the cloudiness comes from dissolved air in the water, I've heard somewhere it can be completely eliminated by boiling the water prior to freezing it. Of course, it probably takes less energy to just chop off the cloudy area..

Frontier Mixologist

Is that an "It's Academic" ruler, I spy? Please tell me you too were on that show? I was on the Baltimore version.

Camper English

Sorry to disappoint- Academic is the brand of ruler.

drink maestro

scrap that.. hearsay and conjecture does not make it so :).


I am having the same trouble with destroyed coolers through ice expansion. what I am trying out at the moment is creating a double bottom, whrere I put a kind of "pillow" that would contract. The pillow has to be waterproof of course and it has to be fixed to the bottom as the material in the pillow would be less dense than water and float.

So far no luck, I was thinking a kind of air filled baloon (problems with keeping it in shape) as well as some foam filled rubber pillows (contract too much from the weight).

Ideally there would be an air filled rubber baloon covering the complete bottom and fixed to it with a nozzle going outside. the nozzle would be sealed with some plug, that would just shoot out if the pressure in the baloon became too much, thus releasing the air in it and giving space for the expanding ice. nice effect would be that you could tell when the block is done: seal out = clear ice ready.

Any thoughts? Ideas?

Camper English

At home I try to just not allow the cooler to freeze all the way; that's the easiest but not always practical.

Just brainstorming here, but if you put the water in a plastic bag and then beneath it put a sponge on the bottom of the cooler (outside the bag), the sponge could possibly take additional expansion of freezing. [I know there are problems with the wrinkles of the bag getting stuck into the ice block; in an ideal situation one could find a square bag that perfectly fits the cooler.]

Similarly, if you can think of a balloon-like object like a raquetball (but something that sinks not floats) that sits on the bottom of the cooler that is food-safe and compresses under pressure; it doesn't matter if it covers the whole bottom I don't think. Hmm, this is an interesting question; I bet we can think of something...


I use a steel gastronome pan (1/2 size approx 9l, 150mm tall) inside a cardboard box that has been lined with expanded polyurethane sheets (wrapped in plastic tape to prevent water/ice damage) and a thermal blanket (that is made of recycled wool fibre wrapped in plastic - this comes with our fresh dog food delivery). The steel pan has the advantage of being a thinner, more durable container and is relatively plastics free (or at least using a lot of materials that would otherwise be thrown away). The steel gastronome can handle the expansion of the ice and the wool insulation+cardboard box are also flexible if necessary.

Camper English

@Krp Nice! I wish Igloo coolers had metal sides but I suppose that would only be practical for our specific application.

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