Alcademics

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.

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.

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.

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

http://iopscience.iop.org/0370-1328/77/3/327

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.

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

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

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

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?

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.

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.

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

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.

http://imgur.com/j0Yh78s
http://imgur.com/AgMxd8F

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

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

http://imgur.com/9RdOj3t
http://imgur.com/E4QP7n5

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.

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

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!

--“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 https://www.youtube.com/watch?v=kl8VcL0DNio, 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.