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Clear Ice Blocks at Home in an Igloo Cooler

This post describes how to make a clear block of ice using a picnic cooler. Since I first wrote it in 2009, I have figured out a lot about ice, but this was the defining post for what would become known as "directional freezing." What is Directional Freezing? (the basic theory behind clear ice). 

An index of all of the ice experiments on Alcademics can be found here. It's also a great place to start. 


Before I figured this out, I tried many other experiments. 

Early experiments were:

And I had success with:

I also learned some ways to cut ice into big chunks.

Now I am trying to refine what I call the Pond Method, the concept that if we freeze water from the top down only (and not outside-in), all the trapped air that makes cloudy ice will be the last to freeze on the bottom of the container, rather than in the middle.

In the last attempt I used a collapsible beer cooler. I had good success in getting clear ice, but found it really hard to get the ice out of a cooler. 


This time I tried freezing water in a hard-sided plastic Igloo picnic cooler. Initially I left the cover closed, but after two days it had only barely started to freeze (a good sign for its insulating abilities) so then propped the cover open.


After a few days when the water looked almost completely frozen and I could see some cloudiness forming at the bottom, I removed the cooler from the freezer. I turned the cooler upside-down and waited for the ice block to drop out of the cooler. Presto! It was ready.

There was a little unfrozen water at the bottom of the block (with only about a centimeter of ice covering it). This was easy to drain.

Full block outside cooler (6)

Then I just cut off the bottom cloudy part and had a big chunk. Easy!

Once again, the secret to cutting ice is to score it about a centimeter with a knife or saw, then chip it away with an ice pick and hammer.



  • I'm really surprised the cooler didn't crack after the ice expanded, but maybe it didn't because there was a little unfrozen water remaining.
  • This Igloo cooler is a totally workable vessel for making clear ice blocks in my home freezer. Hooray! Luckily it is of a shape that allows for easy removal of the ice block.

Future experiments:

  • In this first experiment with the cooler I set the freezer temperature on the lowest setting. I'll see if this matters for clarity or if I can use the high setting for faster freezing.
  • I also want to try a disposable Styrofoam cooler (if I can find one this winter) just because there is no worry if it cracks, and this is the most reproducible vessel for other people to try at home.
  • I should attempt to find a flexible insulating material that can be made into other shapes, such as a tall and skinny shape (thermos?) that would more easily fit in the freezer and can make smaller cubes.

Here are more clear pictures of the ice pulled out of the cooler with some of it unfrozen, and it after smashing off the unfrozen part. 

Clear block_tn
Clear after removing shell_tn


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Mark Fleser

Why not boil the water for 20 minutes or so to release dissolved air.

Camper English

Because that doesn't work. See links in the post.


Once the cooler reaches equilibrium with the freezer's temperature, there will be no advantage to having only one side open to the air. The ice forming on the top has to do with it being 10% lighter than water and thus floating up to the surface. Ice will form on the sides if it can nucleate and stick there (uneven surface, for example) regardless of which way it's being cooled.

Camper English

That makes a lot of sense, but practically speaking it doesn't seem to solve our problem. All experiments I've done with thinner-walled vessels have frozen from the outside-in, including ones in other slick-sided plastic containers.

Maybe the slower rate of freezing in the thicker-walled containers allows all the ice to float to the surface whereas the thinner vessels freeze too fast for that?

I would like to know the answer, though that may be an academic rather than practical question.


Why not try and cool the water just above freezing, place in an ultrasonic batch (relatively inexpensive equipement), then return to the freezer. This will remove all of the trapped air and will not give much time for the air to be re-absorbed in the water.

Camper English

Thanks Chris- I think I am going to try the "personal massager" to vibrate the air out next.

Ben Shipley

you don't need too much shaking. There are japanese ice trays that shake back and forth. The frequency is more waltz than orgasm.

Dude you are a genius. It is the expansion of crystallization in a radiant flow that creates cloudy ice. I just did it. You saved my life genius. You are the man!!!!!
Omg I cannot tell you how much this means to me. You rock. Thank you thank you thank you.

Camper English



I am fascinated by your experiments. I see you've settled on a method but there's 2 more experiments that I don't see on here that I would like to suggest. One is trying to freeze stuff with objects floating in there. The second if comparing the freezing of an open container vs a closed container.
The reason why I suggest floating stuff is that I remember a long time ago when I tried to have a block of ice with an orange frozen in the middle. My memory is hazy but I actually don't remember any cloudy ice. Upon reflection I believe that it's because the orange takes a considerable amount of time to freeze and therefore stays at a temp higher the then freezing point a bit longer then the rest of the water. Since it's floating on top that means that the liquid on top doesn't freeze as fast either and therefore allows air to leave. Thereby avoiding the problem with trapped air from the top freezing first.
The thinking with the closed container is that air is actually a pretty good insulator. When it's an open container the top cools with convection. However with a closed container the trapped air has to cool down to freezing before the water on top starts freezing. The bottom and side should freeze before and top and therefore also avoiding the problem of trapped air.
I'm conducting both experiments now so I'll let you know how it goes.

Camper English

Thanks Gael- I have tried freezing objects in ice with no conclusive results. For the latest ice experiments, go here:

As for the other experiment, I think it is more important that the bottom and sides are insulated with the thick plastic. I don't think it's possible with typical water to avoid cloudiness, we just want to control its direction. But if you find something different, I would love to know!


I did see what you did with Chambord. I didn't think it was the same as floating an object since the point was to prevent the top from freezing and encourage bottom up freezing. You also need a thin walled vessel instead of a cooler.

Both experiments I did were a bust. I did run into a few sites about ice carving and they talked about how they made huge clear blocks. They took huge metal tubs and submerged them in a solution of brine. Brine has a freezing point much lower then water so it works for keeping the sides and bottom cold but leaving the top untouched. Then they installed pumps to keep the water moving on top.

So the next idea is to actually do some work. On a free weekend I'm going to put a large container of water in the freezer and break the top every hour or so before the ice gets thick.

The next idea is a bit more radical. I'm going to try a freeze salt water. Frozen water is a crystal lattice and there is no room for water or salt to be trapped in there. So the idea is to add enough salt so the freezing point is lowered to closer my freezer temp so it will be a slow freeze. As more ice forms the solution will get more concentrated with salt lowering the freezing point even more. Eventually it should reach an equilibrium point at fridge temp where no more freezing occurs. Since the ice formulated slowly it hasn't trapped air and salt which has been pushed into the brine. However the brine doesn't precipitate out the salt and air because it doesn't freeze. In the end you're left with an ice block that has a salty surface that just needs to be rinsed.

Camper English

It sounds like the brined solution trick is similar to my insulated cooler- but very interesting and perhaps will allow people without room for a big cooler in their freezers to replicate this on a smaller scale.

Your second idea- freezing salt water- is very interesting! I wonder what the chemistry of 'making salt come out of solution' at a low temperature is.

Please do keep me up to date on that!


Freezing salt water seems to have made it worse. Although after doing some research my hypothesis on slow freezing seems to be right.

The slower you freeze the lower your air bubbles density in ice. I suspect this is why your cooler solution works so well. Not so much because of the direction of the freezing but because the insulation slows down the freezing considerably. I'm going to measure the temperature of my freezer and then figure out the concentration of salt I need to get a freezing point that comes close. Heck, I just might freeze a range of concentrations of NaCl, KCl, MgCl2 and CaCl2 just so I can get my own paper out of it.


I actually see you made an experiment with temperature as well but your temp range was rather insignificant. If there was a way for you to jack up the temperature to 30F then I'm sure you would see a difference but that probably isn't possible with what you have.


How about a vacuum chamber i.e removing the air forcefully ?

Camper English

Yes that would be awesome. Not sure if it's doable in a non-laboratory setting though- have to get the air out of the water as well as the air around it. Would be fun to try though.

Luke Tullos

The vacuum is unfortunately a little futile. Water will actually "boil" at room temperature when enough atmospheric pressure is removed.


that's the point. water "boiling" at room temperature means it loses the gas, which is what you want to achieve.

Don J

Hello Camper, after reading trough all that amazing stuff I had an idea, that made some sense to me. What if you took your Igloo and let the water inside cool really down, like near freezing point. Then you take a lump of clear Ice and fixate it right in the middle of the water with a fishing line. Sort of a nucleus or bit like the Popsikle method. If my idea pans out the water would first freeze in the middle and you would have a clear block. Just theory right now, but maybe worth a shot

Camper English

Don - I see you know your ice physics, which reminds me I need to type up my notes from that 500 page Ice book I read. Anyway, I think your theory is solid but I don't know if it could be reproduced. I for one don't have that good temperature control in my freezer that I could set it at 32.5 degrees or whatever. But even in a better-controlled setting, I think impurities (such as the fishing line holding the ice in the middle of the cooler)or scratches on the sides also cause nucleation points. (I could be wrong on this.)

Maybe, if that were the case, you could have a super-smooth container cooled to just freezing, with a rough object on the bottom of the cooler that would act as a nucleus, inspiring to freeze from bottom-up? Maybe not, it probably has to be colder than the water.

If only ice sank we would have these problems. Just, you know, a whole lot of other problems.

Thanks for your comment and if you get to try it please keep us posted!

Ed, Birmingham

I am interested in perhaps a bottom-up freeze. Could you have a non-insulated vessel bottom with insulated top and sides? Perhaps an inverted dewar with a Saran or latex (exam glove or some such) closing the orifice?

Camper English

This is something I plan to try: put a plastic bag filled with water in a cooler and turn it upside-down. Hopefully it will freeze bottom-up and clear.

Erik Anderson

Hey there, I'm a chemical engineering major. I just wanted to say that you might have the most success if you try to minimize the number of nucleation sites. Try using extremely smooth containers and try to remove particulates, bubbles, and gas from the water.


Came across this on eBay and thought I'd share. It explains the process as well.

Camper English

Wow, someone built one- that's basically igloo cooler method with a mold inside the top. Thanks for sharing it. I'm totally going to blog this on it's own post.


If you want to make actual cubes, try this method:

Buy some cheap silocone ice cube trays.

Cut a small hole in the middle bottom of each cube space.

Stack them inside the cooler filled with water, making sure they dont start nesting inside each other. You can use skewers to keep them seperate if this is a problem

Freeze the cooler until you start seeing white forming at the bottom.

Remove the big block of frozen material and put it back in the freezer.

Once this is down to a good temperature, remove it and smash the ice brick apart until you have your ice trays out, each filled with clear ice.

The reason this works is because the ice freezing from the top pushes the air bubbles out through the holes in the bottom of the ice trays, allowing clear ice to form in the top trays. (The lowest trays are only there to keep the top trays out of the bubbles. you could use something else to prop them up if you like.)

The holes in the bottoms of the plastic ice trays are small enough that they allow the bubbly water to escape, but not large enough for the ice in the trays to be too well connected to the material below it.

Camper English

Makes perfect sense. Thanks! Have you done this and are the silicone trays easy to break out of the block of ice? seems like that would be the challenging part.

Joseph Eagan

Try using a solution of propylene glycol. This will speed up the freezing process a great deal. I do not know the exact ratio I will try to look it up. This makes a block 12in. Wide and about 17in long in about 12 hours. (Clear) this is a similar method block ice machines use :-) happy freezing!

Camper English

Joseph - Are you suggesting to put propylene glycol in the water?

Interesting as it is apparently used as a de-icer, but I don't think I'd want to serve people ice with that in it regardless.

Cool info though, thanks.


Here's one way I discovered by accident- stack up 3 or 4 silicone ice cube trays (the kind that make the really square cubes) filled with tap water. Some of the center cubes freeze clear because they are freezing so slowly. Not perfect, but it's easy.

Camper English

That's awesome Suzy - I've thought about just putting one of those trays in spray foam insulation for a similar effect. Need to get on that.


What about a chemistry hot plate with a magnetic stirrer (no heat of course)? Would keep the water moving...

Camper English

Yep, that certainly sounds like it would work- at least until the last bit froze. However the beaker would probably need to be insulated so that it didn't freeze from the outside-in, leaving an unfrozen core in the center (nothing wrong with that ice, just would be weird-shaped). It would be fun to try either way.

Renee Jardine

Hi my name is Renee' and I really enjoyed your experiments. Recently, I started a small ice sculpting business in Florida and called Work of Ice. I work with molds a lot and am interested in your freezing objects inside. If you could please email me I would like to ask you a few questions. See what your thoughts are. Thanks!!!!!!!

Camper English

Hi- Here's a post you might read for my attempts at freezing things into ice.


I am an ice sculptor in Canada. The ice machines I have seen act by freezing from the bottom up while having a pump circulate the water. The impurities end u

Aaronp being concentrated at the top of the block. It takes around two days to freeze. This is not in a freezer but in a special block maker that has the cooli g element on the bottom.


Have you tried making the blocks the way that clear ice is formed in nature? Icicles are clear because the form slowly, with small amounts of water freezing in layers. It may take longer, but if you build up the block by slowly adding water, my guess is that it would end up being quite clear.

Camper English

I did try this and unfortunately it didn't work.


I once saw some TV show about a company that makes those ice sculptures out of huge blocks of ice, and I think the way they did it was to have a small pump circulating water near the surface, and I guess it froze from the bottom up. Their ice was crystal clear. Not sure about the type of water they used

Camper English

Yep that's how they do large ice blocks today as far as I know: cold plate on the bottom, circulating water, and they don't let it freeze all the way.


Also, this is interesting.. I always notice in these silicone ice cube trays I have, the cubes get clear on the sides of the tray and cloudy in the middle. Does that mean the cloudyness is related to how fast they freeze? The ones on the edge have more exposure to the cold air. With most regular trays, each cell is surrounded by air.
Sometimes I'll get perfectly clear cubes on the edges. My water comes from a well too.

Camper English

That's the whole trick to the cooler method: it freezes from the top down only. In typical ice cubes they freeze from all sides since they're wedged on the bottom. In those king cube trays they freeze mostly from the outsides-in as well as top-down. The last part to freeze is where trapped air goes, so the more central, the more cloudy.


I put a 3 gallon pail of water in the freezer been there two days it's frozen on the top about an inch how can I make it freeze right threw and faster than its progress it doing now

Camper English

You can turn up the freezer or use less water.


Thanks for this post. I've been using this technique for a few months now with great results.

I've tried using tap water and jugs of distilled, "spring", and "drinking" (minerals added) water from the store. I seem to get the best results with the spring water jug. The others have made blocks with very tiny, vertically oriented streaks of bubbles throughout. My results aren't conclusive though, as I have roommates who could have inadvertently disturbed the freezing process.

Camper English

Yep I often find those bubble trails when the container has been jostled during freezing. You need a Caution: Ice Making in Progress sign. :)


In the lab we helium or nitrogen sparge liquids, that we cannot tolerate air in.

Camper English

That would be fun to try for ice, if not the most practical method for home!


So for the past six months or so I've been trying to figure out how to increase the ratio of clear ice I get using this method. The first photo of a full block in the article above looks like it has clear ice on maybe the top 50% of the block, and the next one slightly better (maybe 65% or so?). But the blocks in these photos look like they're 80-90% clear, and this video shows a similar freeze with only a thin line of bubbles at the bottom. Every freeze I tried gave me a block with clear ice only on the top 50% or less of the frozen block, so I tried changing a bunch of variables to figure out how other people were getting ratios of clear ice that were so much better than mine.

The answer turned out to be water purity. I can now get top-down freezes with only a thin plane of bubbles on the bottom by starting with the purest water I can get, then boiling it to remove the gases, then pouring gently into the cooler to let cool to room temperature, then freezing as Camper recommends above.

(Omitting the boiling step leaves the ice riddled with Matrix-bullet-like striations like the ones Camper saw when using distilled water. Note also that for people in the US, distilled water will probably be the purest you can cheaply get, but they don't sell it in the UK, so I've had to freeze-purify my own.)

All the top-down freezes I've tried with straight tap water or with Brita-filtered tap water have produced about 50% clear ice or worse. For reference, this TDS meter measures my tap water at 280 ppm (which actually might be low for London, although admittedly I don't know whether the meter is calibrated correctly). Filtering once through a new Brita filter barely makes a dent, coming in at 215 ppm. Volvic brand bottled water measures at 94 ppm and freezes slightly better than Brita-filtered, but not much. My freeze-purified water is about 7 ppm TDS.

For further reference, and in an attempt to give the last six months of my life some meaning, here is a list of things that either made no difference to the ratio of clear ice or made it worse:

  • Covering the container with a metal tray
  • Covering the container fully or partially with the cooler lid
  • Covering the container with cling film
  • Covering the container with foil
  • Covering the water with foil touching the surface
  • Boiling tap water or Brita-filtered tap water and freezing immediately
  • Boiling tap water or Brita-filtered tap water and letting it come to room temperature before freezing
  • Putting the cooler lid under the container
  • Using a taller container
  • Using 1-3 layers of bubble wrap as an insulator, with or without foil covering the inside or the outside of the bubble wrap
  • Using styrofoam as an insulator (by cutting pipe insulators the long way)
  • Using more or less water inside the container (between about 1.5 to 6.5 inches deep)
  • Putting a small desk fan inside the freezer blowing across the top of the container (but see below)
  • Freezing when nobody is home (to ensure no disturbance)
  • Changing freezer temperature between -1 and about 15 degrees F
  • Interrupting freeze before bottom had completely frozen
  • Running water through Brita filter up to four times

Side note: the fan inside the freezer, while not making a difference to the ice clarity, does seem to considerably speed up the rate at which anything chills. I now use this to chill glasses -- it now takes about 2 minutes to get a glass as cold as I used to get it in 7 or 8 minutes!

Finally, the one suggestion that I haven't tried yet is to use an ice mold inside the cooler. (I don't have molds yet because I've been waiting for Cocktail Kingdom to restock.) However based on my other experiments I doubt this will make much of a difference, since the quality of insulation doesn't seem to matter very much unless your water is already fairly pure.

My main conclusion from all this is that there are (at least) three big sources of cloudiness in freezer ice: dissolved solids, dissolved gasses, and compression when freezing water expands in the center. Ice will only stay clear when you can get rid of all three factors.

I hope this is helpful for anybody who's running into similar problems!

Camper English

Wow! Thanks for sharing all this info, I'm sure it will be useful to people having similar issues.

My water in San Francisco measured at 132 TDS so that's a lot less than in London.

There is a water filter called Zero Water which filters water down to nearly TDS 0: and maybe that could help eliminate or reduce the need for boiling or buying distilled water.

I would say with my average block (unfiltered tap water) it's 60-75% clear ice and the rest cloudy. But now I should probably try boiling my water to see if it helps. It didn't help before I started using a cooler, but it can't hurt to try again.

Camper English

Actually I was wrong and my TDS is even lower:

San Francisco Tap Water, Average = 132 ppm
Camper's Tap Water = 32 ppm
Camper's Tap Water, after filtering with Mavea water pitcher = 28 ppm
Camper's Tap Water, after filtering with Zero Water pitcher = 0 ppm
Distilled Water (purchased), no minerals added = 0 ppm


Wow, that's some tidy tap water you've got!

Boiling doesn't seem to make any difference for me unless I've got lines of bubbles in my ice, and that doesn't seem to really happen except with distilled(/very pure) water. I think that this is because distilled water is pure enough that it readily sucks the air around it into solution, whereas water with a bit of solids in solution is stable enough that it doesn't do that. In my experiments, purification reduces cloudiness (solids), whereas boiling reduces bubble trails (gases); so it may not make much of a difference to your rig.

Thanks for the link to the ZeroWater filter. When I look on the UK Amazon site though, 6C ZeroWater filters start at the low low price of $110, and $85 for replacement filters! (Usually that sort of price difference means they're simply shipping the US product overseas.) At those prices it'd probably be better for UK icemakers to simply install a reverse osmosis system. Yet another data point to support the theory that pure water isn't in very high demand over here...

Camper English

Good point and interesting theory about the boiling vs low mineral count in cloudiness vs bubbles.

Not only is pure water not in high demand there, Brits are historically stingy with the ice :)


Indeed. I've been to a lot of restaurants and cafes here that don't even own a freezer. Open-fronted fridges are also the norm for drinks in shops. Mm-mm, love that warm Coke!

On an unrelated note: for some reason I can't see the last four comments on this thread unless I click through from the recent comments sidebar (and when I reply to one of them they disappear). Not sure how my browser could be doing that -- maybe the Typepad server needs a kick? Anyway hope that helps in case anybody else is having trouble commenting...

Camper English

Comments: Typepad does a stupid thing where there is a "Show More Comments" link at the bottom of the page (when there are lots of comments) too close to other stuff so you wouldn't notice it unless you went looking for it. Maybe I'll contact support and see if I can manipulate it somehow. Thanks for the reminder.


The "American Peoples Encyclopedia" says round clear ice is made by bubbling air through a tube of water during the freezing process. Dissolved gasses are swept away by the bubbles. Impurities left in a small amount of water at the center of the ice is then sucked out. While the ice dose have a hole in the center, it is clear.

Camper English

"dissolves gasses are swept away by the bubbles" doesn't make any sense to me. Do you have a reference to that you can share?


Just a note, for those without enough room to perform this. I recently got a yeti rambler colster to keep my canned drinks cold, I found that if you cut the top off of a can you can make ice cylinders in the can using the coozy for insulation. The can also will allow you to pour hot water into it if you want to boil the water first. This is similar to using the insulated mug to make ice spheres but much less work intensive. I'd put a picture here but not sure how.

Captain Quirk

--“Once the cooler reaches equilibrium with the freezer's temperature, there will be no advantage to having only one side open to the air.”

No, that’s incorrect. It doesn't matter that the temperature of the air may be the same as the temperature of the insulation. The point is that the insulation (by definition) keeps heat from passing through. If that were not the case, there would be no point in wearing a coat in cold weather. The insulation of the cooler (with the lid off) allows the water to freeze from the top down, which is what you want, for the reasons I explain below.

--“The ice forming on the top has to do with it being 10% lighter than water and thus floating up to the surface.”

No. The ice doesn't form at the top because it's lighter, it forms at the top because that's where the cold air is. (Remember, you’re leaving the top of the ice chest open, and the bottom and sides are, of course, insulated.)

Commercial manufacturers of large ice blocks (e.g., for sculptures) have special equipment using liquid coolant that allows them to freeze their ice blocks from the bottom up. (See, for example.) It doesn't matter what direction you go – from the top, from the bottom, whatever. The point is simply that it has to be directional.

That’s because if you allow the ice to form as it normally does in an uninsulated container like a regular ice tray, it freezes from the outside in (from all directions), leaving a thin layer of clear ice on all sides. But that’s not what you want – you want a single thick layer of clear ice. That’s why you have to make the water freeze directionally, from one side. (And unless you have the aforementioned specialized commercial equipment, that “one side” means the top, because that’s where the cold air in your freezer is, in relation to the water in your container. Water is heavier than air, so the water is on the bottom and the cold air is on the top.)

So why not just let it freeze all the way through?

Because ice expands when it freezes, and as it freezes and expands toward the center, that expansion obviously has nowhere to go. So you have the proverbial immovable object confronted with an irresistible force. Something has to give. The result is that when the center finally freezes, those large compression forces cause the ice to fracture, creating thousands of tiny cracks and bubbles and fissures, resulting in a cloudy appearance.

So you want to stop the freezing process well before the ice block freezes all the way through. (Best results are when you stop the freezing at about the halfway point or earlier.) And you want it to freeze in such a way that when you stop the process, there is a thick layer of ice on one side (in our case, the top), not a thin layer of ice on all sides. The way you do that is by putting the water in an insulated container like an Igloo® with the lid off so it freezes from the top down.

Captain Quirk

No, it means the water is turning into water VAPOR. Which then escapes your ice-making container and fills the vacuum chamber, ruining your efforts to turn it into ice.

In any event, it's NOT the dissolved air in the water that makes ice cloudy when you freeze it. It's the fact that it freezes from the outside in, and the fact that water expands as it freezes. As the freezing water/ice expands toward the center, it compresses that central region (which has nowhere to go) until it fractures and fissures and cracks (oh my!), resulting in cloudy ice.

The trick is simply to use Camper’s method – put water in an ice chest with the lid off, put it in the freezer for around 24-31 hours (give or take, depending on the size and shape of your cooler), then take it out, let it thaw a bit so the half-frozen ice block is easy to remove, then use a hammer or something to break off the ice shell that encases the non-frozen water, leaving a clear frozen solid 1/2-block of ice. I use regular tap water. Not distilled water, and I don’t boil it. And I get great results – perfectly clear ice for my drinks. (Admittedly, we have pretty good tap water in my area, so if your water quality isn’t good, then maybe using distilled water is the way to go. Especially if you're in Flint, Michigan, heh heh. But for most, if not all, people, air dissolved in the water is NOT the reason it turns cloudy when you freeze it, and therefore trying to boil the air out of it won’t make any difference.)

Camper English

While the cracking due to expansion is a sure thing, why do you say it's not trapped air also? The bottom of a cooler has very much lighter/airy-seeming ice in it. Just curious as to why you think it's not also air, as I've being going on that theory for a long time (in addition to cracking).

And/or, can we think of a way to test that? I feel that when freezing in a conventional method from outside-in, the water remaining in the center sloshes around, showing increased air. I guess that would be a good way to test this; just to freeze something in a large enough non-insulated container to see if there is air in the inner bubble....


Hey Camper,
I'm trying to get clear ice inside a plastic ball (that gets sealed) so the cold lasts longer. I've tried a nucleating agent but now am trying to eliminate the air. The problem is that some of the water leaves the ball when trying to eject the air/impurities through the hole so I end up with less phase-change material. Is there another was to eliminate the air while keeping 100% of the water inside?

Thanks for starting this exciting topic!

Camper English

Hi Samuel - I'm not quite sure I understand your set-up. But ultimately if the goal is to eliminate the air from the water I'm not sure that anyone has accomplished that yet using vacuum-style technology (nor boiling).


I havent read all the comments and all the articles/experiments you have written. But I just tried to do this with a stryofoam cooler. Got it off amazon. It worked but I probably should have taken it out of the freezer sooner. While the bottom wasnt full frozen. The ice push through the bottom splitting it. So it couldnt be used again. Dont like this because I cannot reuse it now. Also, I left the cooler upside down in the sink hoping the ice would fall out. It never did and the top seemed to be melting quicker that the bottom would release. Makes sense since the top is not insulated. I even tried to run warm water along the sides and bottom. It never released. I ended up getting impatient and just cutting the styrofoam away. I ended up with a nice clear block with just a small layer of cloudy bit on the bottom.

I have another container and may give it another try. This time either taking it out before the bottom fully freezes or by letting it sit in a warm water bath so the bottom and sides warm first.

Camper English

Thank you for sharing. The first time I did this it was in an insulated bag, and couldn't get most of the ice out of it as it expanded when it cooled. Luckily the cooler shown is the shape that allows the ice to slide out relatively quickly. Many do not.


Have you ever tried do double or triple freezed it in the igloo? I read this somewhere.

The bottom line, however, is that Japan is much more geared up towards producing ice, and therefore luxuries such as the slow-frozen stuff cost a fraction of what they do in the UK. But a similar effect, at least when it comes to slowing down the melting time, can be achieved by double (or even triple) freezing ice – a technique that’s fast becoming a staple USP for high-end bars around the country.

Wood explains: ‘You simply freeze your ice once, and then take it out of the freezer and leave it for two to three hours, so that the outer layer is partially melted, and then refreeze it. This has the effect of forcing air out of the ice, producing ice that melts much slower.’

Camper English

That doesn't make sense to me, since in a regular cube the cloudy part is on the inside. And in a cooler it's only on the bottom. Refreezing was one of the earliest experiments I did (but I melted the whole thing and refroze it) and it didn't work for me:


Really interesting read. I have been using a small igloo cooler in my freezer for the top down clear ice method. Works great. Even in Las Vegas, with super hard water, the ice comes out crystal clear. I try to take it out of the freezer when just the top 3 inches are frozen, that way I don't have to cut the whole cube in half (which is a pain in the butt to do smoothly). The 3 inch thick piece of ice is really easy to work with to make 12 large cubes.

Camper English

That's pretty much what I do at home, unless I forget it too long in the freezer then have a whole block to deal with. But now I'm getting much better at being able to break up a whole block with just a 3-pronged ice pick in a few minutes.

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