Tag: making clear ice

Does Refreezing Clear Air-Free Ice Result In a Large Clear Block?
This is an experiment in my ongoing project to make clear ice. I've figured out a way to do it using an Igloo cooler. This experiment is an attempt to make clear ice without one.

A long time ago, I tested the theory that freezing, thawing, and refreezing water makes clear ice blocks. After 13 tries I determined that it refreezing water does not make clearer ice.

However, it recently occurred to me that I could test out something else. If we take just the clear part of ice (leaving behind the cloudy, air-rich stuff), melt it and refreeze it, will the new ice be clear?

A bar in San Francisco refreezes their Kold-Draft cubes. One bartender told me he thought it makes clearer ice than with just tap water, but still not completely clear.

If this experiment works, then someone anyone could refreeze small bits of clear ice into large blocks. Efficient? Nope. But interesting.

(Oh, and long story short: this experiment was inconclusive. Don't want to make you read if you're not into it.)

Anyway, step one was to make clear ice, as I do using the Igloo cooler method. I made two partial blocks of ice. I let the water freeze in the cooler, then knock off the thin skin that forms around the bottom of the cooler (full of water).

Then I took these two clear slabs, broke them into large chunks, and put them into the cooler to melt.

After it melted, I refroze it.

The ice in the picture above is upside-down from how it was in the cooler. Here's a closeup.

At first view, it looks a little cloudy in the middle of the bloc- but I think that's because I had to move my refrigerator a couple of times during this process and jostling the container does seem to make cloudier ice.

Looking just at the cloudy part at the bottom end (top in the picture above), I can't really say whether it's less cloudy than it is with regular tap water. This experiment is inconclusive.

My theory is that as the water cools down or warms up to room temperature it reabsorbs a standard amount of air, and this experiment won't work. However:

If I repeat this experiment (and I probably will), I should:
- Make the clear ice as normal, but not break up the slab into chunks. This saved time but probably adds air.
- Use more refrozen water in the cooler when refreezing. Here is was a little too hard to tell what percentage of ice was cloudy, so I could not compare it with the time I did this experiment with regular water.
The icesperiments continue!

An index of all of the ice experiments on Alcademics can be found here.
November 5, 2010
Making Clear Ice Without a Cooler
In a set of experiments, I showed that you can make clear ice by controling the direction of freezing. The container I've been using for this is an Igloo cooler. When using it, the ice freezes from the top-down and all the cloudiness in the ice forms at the bottom of the container rather than in the middle of the block.

I wanted to show that you can do this without a cooler as long as you have some sort of insultation that accomplishes the same thing as the cooler. In this case, I chose a bigger pool of water as an insulator.

As a control I froze a plastic take-out container of water in the freezer.

As usual, it is cloudy over a large area, mostly in the center. This is because the water freezes from the outside-in. The last part of the ice to freeze contains air and any impurities, and is cloudy.

So then I took the same container and put it into a larger container. The smaller container sits on cubes to keep it off the bottom of the larger container.

Both containers were filled with water to about the same level. The purpose of this is to use the outer container of water as an insulator. The water inside the smaller container would then freeze only from the top-down instead of outside-in, because the water surrounding it would freeze later (because it is so big).

The results show that this worked- the cloudy part of the ice was the last part to freeze at the bottom of the container.

What this means:
- Directional freezing works as long as there is an insulated jacket around the container. The ice freezes only from the top-down, pushing the cloudy part to the bottom.
- This property could be exploited to make an ice cube tray that makes cloudy-on-the-bottom ice. Picture, for example, an ice cube tray that was insulated with a jacket on the sides and bottom.
- So now I can do more experiments to make an insultated jacket that is practical.
An index of all of the ice experiments on Alcademics can be found here.
October 22, 2010
Another Ice Banner Attempt

You may think all I do is futz around with ice all day, and you'd be mostly correct (for proof, see the index of all of the ice experiments on Alcademics here). I attempted to make another site banner today using a clear piece of ice stamped with ALCADEMICS, but I think I like the orange peel one (too big as it is) better.

Click it to see it bigger if you're interested.

May 27, 2010
Making Crystal Clear Ice in Wired Magazine

Run screaming to the newsstand to pick up the June issue of Wired magazine, because there is a story by me in it. Sure it's only 100 words long and it's about how to make clear ice, something you may have read about here, but you can consider it a collector's item.

Update: The article is online here.

May 25, 2010
The New Alcademics Banner

My experiments with ice continue. I've got a routine down to make clear chunks of ice and now I'm experimenting with freezing objects into it. As you can see I have some room to improve but I did make a groovy, if a bit large, new banner for Alcademics.

May 14, 2010
Does Freezing Water in Layers Make Clear Ice?
Here's a new edition in my ongoing ice experiments. So far, there experiments have been:
With successes in:
- Releasing Air Trapped in Ice
- Cutting Corners to Make Clear Ice
So far my conclusions have been that (at least with my San Francisco water), temperature and filtering have less of an effect than trapped air that migrates to the center of the freezing cube. Thus I am trying to minimize this effect.

In this experiment I froze ice in layers in small lasagna pans to see if we had a maximized surface area, hopefully no air would get trapped in the ice and form cloudy parts. Apparently some commercial ice machines such as Kold Draft spray an upside-down mist of water in layers, so this would be the home approximation of that.

I tried this experiments with tiny layers, medium layers, and large layers in the same sized pan, the difference being that I added more water per layer. I let the water freeze before adding another layer.

As you can see, none of the layers turned out clear:

(Tiny layers, medium layers, and large layers left to right.)

The small sized layers were made only adding a couple of ounces of water at a time, so I can't get much smaller layers than these unless I use a spray bottle.

We'll have to call this one a failure. Freezing water in layers does not appear to make clear ice, just ice with smaller layers of trapped air.

Below is a closeup of the layers for your ice ogling enjoyment.

An index of all of the ice experiments on Alcademics can be found here.
November 19, 2009
Cutting Corners to Make Clear Ice
In an ongoing set of experiments I've been trying to make clear ice at home. I've tried:
With some success on the last one. While what would be ideal would be to produce one giant solid block of perfectly clear ice, I haven't figured that out yet. However if the ice is going to be used to shake with or for cooling individual beverages, you don't need a giant block- just big chunks.

There is a way to accomplish this by cutting corners. And tops and bottoms. We've seen how the air bubble makes the cloudiest part of the ice in the center in vertically-frozen water, and mostly along the bottom of horizontally-frozen water.

And I've also found that horizontally-frozen water usually has an edge of very clear ice.

So with my ice pick, I just cut off the clear edges separated the top from the cloudy bottom
of the pan ice (easier than you'd expect, as the cloudy ice breaks off easily), and cut around the cloudy middle of vertically-frozen water to end up with a big bowl of clear ice.

Conclusions: You can make clear ice by cutting around cloudy ice frozen in large blocks. However, you waste about 85% of your ice, and a lot of time.

An index of ice experiments on Alcademics can be found here.
October 23, 2009
Making Clear Ice by Releasing Trapped Air
[update: after this post, I figured out the trick to making clear ice – check here for the solution.]

Finally, I've got a minor success in my clear ice experiment to share. So far in an attempt to make perfectly clear ice in my home freezer, I've tried:
Noting that water freezes into ice from the outside-in, leaving an air/water bubble that forms the cloudy part of ice, I sought to devise a way to either change the way ice freezes, or to release the trapped air while the ice was freezing.

First I tried laying a bar spoon diagonally through the water. The theory was that the metal of the spoon might conduct coldness into the center of the ice so that the ice would freeze more evenly. The intended result was a dispersed air throughout the ice rather than just in the bottom/center layer.

But alas, the intended result did not happen. There does appear to be more air dispersed in the ice, but still the majority of it is in a layer along the bottom.

Next I tried inserting a straw into the center of a tray of ice to see if the air would escape through the straw. The plan was flawed to begin with, as water would probably just freeze inside the straw so no air could get out.

In reality the freezing ice pushed the straw up so that it was only inserted about half an inch into the ice by the time it was fully frozen. This had no effect on the amount of cloudiness.

For something that did work, keep reading after the jump.

(more…)
October 23, 2009
Does Hot Water Make Clearer Ice Than Cold?
I have been doing experiments at home to try to get the clearest ice possible. So far my experiments have compared:
- Distilled vs. Tap water
- Multiple melting and freezings of water
I have not yet had success. Will the third time be the charm?

(*Update – You might want to skip to this index page to see conclusions reached after many experiments.)

This time I compared hot water to cold water to see which would freeze more clearly. The theory is that hot/boiled water has less trapped oxygen in it, and thus will freeze clearly because there will be less air bubbles.

As I previously saw no significant difference in ice clarity between using tap vs. distilled water, I began with unfiltered tap water. One batch of water I left at room temperature. The other batch I boiled for several minutes. I put them in the freezer while the hot water was still hot. Here is what happened on three separate attempts:

The cold water actually looks a little more clear, but this could be because when the center of the hot water finally froze, it burst. I can't guess why this is because it's not like I have a super refrigerator that freezes ice in ten minutes.

Another theory about why the first experiment failed is that as the hot water cools down in the freezer, it reabsorbs oxygen and acts just like cold water. To test this, I repeated the experiment, this time covering both plastic tubs with the lid before freezing.

Here the hot water ice looks slightly more clear than it did when it was uncovered. However, I'm not seeing a significant difference in hot vs. cold water, though the covered hot water may be just slightly clearer.

Conclusion: Hot water does not freeze significantly clearer than cold water, even when the vessel is covered to reduce oxygen re-absorption.

In all of these ice experiments so far, the major cloudy factor in the ice has not been cloudiness throughout the ice, but a cloudy spot in the center of the ice. This spot is assumed to form due to the order in which ice freezes, from the outside-in. The oxygen migrates to the liquid part (in the middle) until it is the last part to freeze. Kold-Draft ice machines produce wonderfully clear ice cubes in part because they freeze the ice in layers- water is sprayed in layers from the top down, so that oxygen is never trapped.

Is there a way to freeze ice in a home freezer similar to a Kold Draft machine? Can we manipulate the way water freezes or change the shape of the container? Can we vibrate the container or stir the water so that the surface stays liquid and freezes last?

We shall see, in future ice experiments.

*Update – For a solution to the ice problem, see this post for a method that works. Also, an index of all of the ice experiments on Alcademics can be found here.
October 23, 2009