Category: ice

You can make a clear block of ice using an insulated cooler with the Directional Freezing method. You can also use this method to freeze objects inside of ice blocks including freezing a full-sized bottle inside an ice block.

If you are able to add an aquarium pump to the mix, you can make clear ice from the bottom up without any cloudy parts at the end; a method that mimics how professional ice block machines work. 

(All of the many, many ice experiments posts are located here in the Index of Ice Experiments.)

Today we'll talk about how to make clear ice with an aquarium pump and no cooler, and how this same method allows us to freeze objects in an ice block also without an insulated cooler.

While I've always favored the non-electricity Directional Freezing method, Alcademics reader fang2415 prefers to use an aquarium pump without (much) insulation. This takes up little less space in the freezer, and it seems like a much faster method than with insulation – as below, he says he gets a 4-liter ice block every day! 

In short, fang2415 places an aquarium pump at the top of an uninsulated container of water in the freezer, just barely insulating the top of the container with bubble wrap to help prevent it freezing over. He then found that this also works to freeze objects inside ice blocks. 

He describes the method:

The method is really simple: basically it's the same thing I now do to make most of my ice using an aquarium pump in a plain Tupperware-style plastic 5L container, but this time I threw a bottle inside the container and used tinfoil as a cover since the bottle was too tall for the lid to it.

 

I've been making all my ice this way recently, and every day I get a big beautiful 4-liter-or-so block of ice. The only real annoyance is cutting the pump out. 

I filled the container up to about .5 inch from the top and stuck my 150 L/H aquarium pump to the side just below the surface. Usually I aim the pump so that the outlet goes across the middle of the surface, but this time I kept it to one side so that the jet went around the side of the bottle's neck.

I've found that insulation barely matters with the pump method, although I usually cover the top with two layers of bubble wrap to reduce freezing at the top. Tying the bubble wrap with string works just fine; it just means that you need to knock the top ice-collar off at the end.

After chiseling the pump out (which is probably the most difficult part of the process), I had a bottle with the top conveniently exposed inside a large squarish block of clear ice. 

He then chisels out the aquarium pump and cuts or runs water over the outside edges to smooth out the block of ice and make the bottle label more legible. 

Thanks once again to dedicated ice nerd fang2415 for not only doing the experiments, but for taking pictures and sharing with the Alcademics audience!

Related articles

Making a Clear Ice Block from the Bottom Up

Clear Ice Cubes Using a Tray in a Cooler

Make Perfectly Clear Ice Balls Using Insulated Mugs

How to Carve Up an Ice Block, Tools to Use, and Making Clear Ice at Home

Behold the Glorious Index of Ice Experiments on Alcademics

I've done a few years' worth of ice experiments here on Alcademics, and sometimes bartenders contact me on how to solve ice problems. (That should be my new reality show: Ice Whisperer.) 

Here is the index to the ice experiments on Alcademics, where you'll find how to make clear ice blocks, clear ice cubes, clear ice spheres, and many other ice successes and failures. 

One bartender was curious about some ways to present bottles in ice yet still be able to read the labels. I presented a few ideas and have probably found a solution that works for the bar (that I'll share when it's open), but this method is something that does work but wasn't a great fit for that particular program. 

Anyway, enough with the backstory. Look at this cool spinning bottle!

This technique uses directional freezing (freezing inside an insulated cooler with the top off so that it only freezes from the top-down), with the bottle raised high so that it's in the clear part of the ice block. 

Method for Freezing a Bottle in a Clear Ice Block: 

1. Fill a picnic cooler with water.

2. Place some sort of stand on the bottom of the cooler. I used a plastic box in one experiment and an oversized metal piece that looks like a napkin ring in another. Anything that lets water move through it is ideal. 

3. Place the bottle on its side, diagonally across the cooler. Note that very tall bottles may not fit in your cooler. Fill the cooler with water to an inch or two above the bottle. 

4. Leave the top off the cooler and let it freeze for a couple of days. 

5. When the block freezes either all the way through to the bottom of the cooler, or (better year) just to the point at which it starts to become cloudy at the bottom part of the block, remove it from the freezer. Tip over the cooler and let the block slide out. 

6. Let the ice slowly warm to temper it, then use an ice pick (the three-prong one is my preferred tool for this task) to scrape off the cloudy section. You can break off the cloudy ice in any creative way you want. As you can see, for the Tanqueray I did a super cool nugget-style chipping, while for the Plymouth Sloe Gin I did a scrape on only one side so that it's super flat on the front surface. 

As you can see, the top of the bottle is at the corner of the block, so you can easily open it and pour from the bottle still.

Example One

Looking down on the cooler with a big napkin ring at the bottom on which the bottle will sit.

The bottle sits on the stand with enough water to cover it.

From the bottom: Now to chip off that cloudy layer!

Ta Da!

 Example Two

Frozen block with bottle. You can see the yellow of the plastic open box I sat the bottle on.

Enjoy.

Related articles

Hey, Who Put Science In My Drink?

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.

The equipment is specifically the:

• Tovolo Sphere Ice Molds
• Rubbermaid 10 qt. Victory Personal Cooler 

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. 

Method:

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.

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:

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

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.

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.

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

The index of all ice experiments on Alcademics is here. 

Related articles

Hey, Who Put Science In My Drink?

You may recall from a billion years ago I found a clear ice maker that works similarly to the directional freezing/Igloo cooler method. It was the Polar Ice Tray and I wrote about it here.

Now the same company has launched a clear ice ball maker and they sent me one to test out. So that's what I did.

Long story short: It worked great on my first trial, but not every time. 

The Polar Ice Tray works just like the directional freezing method of making clear ice balls (read about that here or all the ice experiments on Alcademics here): The container is insulated on all sides but the top is not. The ice freezes from top-down, pushing trapped air and impurities downward. 

What this product does is offer an easy way to get the water into the molds and the balls out afterward. It's shaped like a little tug boat. 

The outer blue container is just softish foam. Inside there is a top and bottom half of the ball mold (this model comes with animal shapes that are pressed into the top), and a bottom water receptacle. 

The bottom half is perforated so the cloudy part is pushed into the receptacle. To use it, you fill water in the little spout and then let it freeze for a day. Here it is after freezing. 

The cloudy part of the ice is on the bottom. 

Now for the big reveal. 

It is super easy and the spheres are nice when they come out perfectly. It may be more space efficient than the insulated mug method for two spheres, depending on whether your freezer offers more horizontal or vertical space. 

However, on subsequent uses, I've found the tray can separate during freezing, spilling water out the sides and making incomplete ice balls – only partial spheres because the water has leaked out the sides. So you need to make an effort to get a really good seal on the different parts that fit together. I tried and still failed twice. 

So far I've used the tray 10 times and 7 of those times it worked and 3 times it failed. (For the record the insulated mug method has never failed me.) If I discover a good way to ensure a seal I'll update this post. 

The tray is a bit pricey at $55 plus postage, but I spare no expense for ice! You can buy them on the Polar Ice Tray website.

Related articles

Peru, Bird Poop, and the Birth of the Agro-Industrial Complex

All of the Boxing Room's Cocktails, Premiering Tonight in San Francisco

Bars, Restaurants, and Sights of Lima, Peru

Distillery Visit: Bunnahabhain Single Malt Scotch Whisky on Islay

Alcademics reader and ice nerd Mike Palmer has come up with an easy if not space-efficient way of making clear ice cubes using a silicone tray and a cooler.

The short answer is: poke holes in the tray and set it on a riser at the bottom of an insulated cooler.

The long answer? Palmer wrote it himself below.

How to easily make perfect clear ice cubes, repeatably, from a tray

By Mike Palmer

Here’s an easy way to make clear ice cubes in your freezer using an ice cube tray, obviating the need to carve individual cubes out of a block of clear ice.

What you'll need: A small "Igloo" type cooler that fits in your freezer. A flexible, silicon ice cube tray with holes punched through the bottom. Something to make those holes, perhaps along with a piece of soft wood. A paper or Styrofoam cup. A rock. And of course, a freezer.

If TLTR, skip down to “How to do it.”

Background

I became obsessed with trying to make clear ice cubes at home (and later, clear ice spheres) after watching David Rees' How to Make an Ice Cube in his "Going Deep" series on the National Geographic TV channel. How hard could it be? (Ha!)

BTW, after finally succeeding at making clear ice cubes, I found that there are tangible benefits from using them in your drinks. (Even if drinking water.) In addition to lasting longer (because they’re pure ice and not ice/air), clear ice cubes also taste better because they’re pure ice. That is, they don’t have yucky tasting freezer air in them. Also, women like the aesthetics of clear ice and they notice—and like—the sound clear ice cubes make clinking in a glass. (Sure to please.) Freezer cubes don’t clink. They clunk. And now you’ll notice every time you hear a sound track in a movie or on TV.

In Theory

In David Rees’ TV program, he showed how clear ice forms in nature when a body of water slowly freezes from the top down with a substantial mass of warmer, unfrozen water underneath. (Alcademics readers knew this back in 2009. See https://www.alcademics.com/2009/11/another-clue-to-ice-clarity-slow-freezing-like-a-japanese-pond.html.)

And he suggested on his website that you could make a block of clear ice by kinda imitating nature, by letting a pan of water cool in a freezer. Although that’s not really imitating nature since the water in the tray freezes from the outside in on all sides.

So freezing a pan of water does not make a clear block of ice, as even Mr. Rees concedes. Air still gets trapped in the middle, so you have to cut the “outer edges of your ice block” to harvest clear ice.

And even if the block were totally clear, you would still have to carve away at it to make individual cubes. And then you’d have to smooth six edges of each cube. that’s very time consuming, not to mention dangerous, working with sharp edged instruments on slippery ice.

Rees’ suggestion for making clear ice works better if you use the slow freezing method, using a dorm style fridge set to 30 degrees, as Mr. Kevin Liu has suggested. https://sciencefare.org/2012/07/12/weird-science-ice-premium-ice-home/

[note: the above link redirects to spam, try the Internet Archive version instead: https://web.archive.org/web/20150316061948/https://sciencefare.org/2012/07/12/weird-science-ice-premium-ice-home/]

But you still get air in your cubes that way. Here’s a photo of an ice cube made that way. Air is still trapped in the last part of the cube to freeze. In this experiment, with only the center trays filled, that’s the bottom middle.

(I hypothesize that air is sucked into the cube when the last bit of water expands as it freezes. It lifts the cube up and pulls a vacuum underneath. Interestingly, air gets trapped in different places in the different cubes depending on whether a cube has a sister cube (or cubes) next to it. You can tell what position in the tray the cube had come from based on the distribution of air trapped inside it. In one experiment, I filled the tray in a checkerboard fashion, so that no cube shared a side with another cube. Only their centers were cloudy.)

In Practice

What to do? I tried the slow freezing method, which was supposed to do the trick. But it didn’t.

Fortunately we have the Internet. After searching around on youtube and seeing people consistently recommend “directional freezing,” I found Camper English’s Index of Ice Experiments on Alcademics. Camper was years ahead of everyone else.

In Camper’s landmark experiment, he found that freezing water in molds in a cooler (that is, from the top down) gave clear ice.

Except that air got trapped in the very bottom of the ice.

Why was that? Although Camper’s technique imitated the directional freezing aspect of nature, there was at least one other aspect missing: the large thermal mass of liquid water underneath the ice.

So, building on Camper’s experiment, I placed a silicon ice cube tray on top of a large Styrofoam cup (as a stand) in a cooler. I filled the cup and I filled the cooler to the top of the ice cube tray. (That brought the water level halfway up the cooler. More on the optimal water level later.)

I put the cooler in a high-end prosumer freezer, which was set at 0 degrees F, the government’s recommendation for food safety. (I checked the temperature in two places simultaneously using two digital thermometers in different locations in the freezer.)

The result of this experiment was much better, but I still got a little bit of air trapped in the bottom of the cubes.

If you look at a close up Mr. Liu’s ice cube https://craftcocktailsathome.com/wp-content/uploads/2012/07/IMG_6874.jpg, his is not perfectly clear either.

I hypothesized that there was still one more aspect of nature missing from this experiment, and that was that, unlike a Japanese ice pond, the water in the ice cube tray could not interact with the unfrozen water below it. One needed holes in the bottom of the ice cube tray for trapped air to escape.

At the same time I came to this “Eureka!” moment, I found that a reader on the Alcademics blog had made the same observation. Furthermore, this idea was consistent with a suggestion on the blog of suspending a spherical ice ball mold upside down, above a pot of water, with the mold’s fill hole in the water to make a clear ice sphere. (Or similarly, the suggestion to put a spherical ice ball mold upside down (hole down) in a mug of water so that the water in the mold could interact with the unfrozen water below in the mug.)

So here’s what I did.

How to do it

I took an acid brush and used the tube end as an auger to bore holes in the bottom of a silicon ice cube tray. Any similar tube will work. A 9mm shell casing would probably work too. (A .38 caliber casing is too large but works well on spherical ice molds.)

I got my trays from Amazon, if you look closely at the photos of the ice cubes on the Amazon product page, you can see air trapped inside them.

I used a Dremel tool with a cone-shaped cutter to grind a knife edge on the end of the tube. I put the ice cube tray on a piece of soft wood (to act as backing for the work) and pushed the tube into the bottom of the tray while rotating the tube. (If you use the end of an acid brush, you need to rotate it CCW so that the tube doesn’t unwind and open. If you use a shell casing, you can hammer on the casing (on the soft wood) to punch your holes through.)

Take a Styrofoam cup and cut it down to about an inch as a stand for the ice cube tray. (I started with a full size Styrofoam cup, but you’re just wasting water if you fill the cooler half full of water. And by using a one inch cup, the tray is lower in the cooler, resulting in better directional freezing.)

Put’s a rock in the cup to weigh down the cup. Else, the stand floats off the bottom of the cooler.

Put the tray in the cup that had the rock in it and filled the cooler with water to the top of the tray.

You might want to jiggle the tray a bit after you put it in the freezer, to knock air bubbles out that might be trapped underneath the tray.

Wait about 18 hours. Timing is somewhat critical. You want to catch the freezing process just as ice has formed below the tray. If you wait too long, all the water below the tray will have frozen and you might get air in your cubes. Remember, in the Japanese pond, there is always unfrozen water below the clear ice.

After the water under the tray has frozen, take the cooler out of the freezer, place it upside down in a sink and set a timer for about 10 to 20 minutes in case you forget to baby sit it. In about 10 or 20 minutes, you will hear a thunk as the ice block releases from inside the cooler. If you timed it right, a lot of water will eventually drain out of the cooler. (A cooler with the drain plug might be interesting. We could use compressed air to blow the ice block out.)

You will be greeted by a strange formation of ice crystals and a cavern of sorts from where unfrozen water drained. (Apparently the cooler isn’t as well insulated on its bottom as we would like, since ice forms there. Since cold air descends, shouldn’t coolers be twice as thick on their bottoms as they are on their sides? Maybe we should put a cooler in a cooler?)

Break the clumped ice away from the ice cube tray, push the cubes out of the tray from behind, and viola! Perfect, clear ice cubes.

Allow your cubes to temper for one minute before using them in your drinks to avoid cracking. 

Now you’re ready to do it all over again and make another batch!

High Strangeness

When I first tried these experiments, I started with the minimal amount of water, not knowing what the right amount of water underneath the tray should be.

I made a spacer that was only a half inch high.

When I did that, something strange happened. I got an extrusion of cloudy ice during the freezing process!

It has always been a corner cube that extrudes in all my runs. All the other cubes are clear. That’s gotta be telling me something.

So then I went the other way, putting more water in the mix by using a plastic beverage cup as a stand for the ice cube tray. I let the water freeze almost completely and didn’t get any extrusions. Let’s hear your thoughts about what’s causing the extrusions.

You can see how the water has frozen at the bottom of the cooler, again demonstrating that the bottom of the cooler is not as insulated as it should be. In any event, there’s enough clear ice below the tray to give us clear ice cubes. (Notice some air bubbles just below the tray.)

Ever being an engineer, I wondered what the “optimal” (minimal) amount of water was for this process. I kept shortening the cup until I got to one inch. Since I knew a half inch was too little, it seems that one inch is optimal. One inch seems to be about the same distance in the photo above too.

I can now make perfect clear ice cubes repeatably in less than 24 hours without a lot of waste.

—-

Thanks Mike! 

Read about all the ice experients on Alcademics by following this link. 

Nearly five years ago I figured out a method to make clear ice blocks in a picnic cooler in what we now call the Directional Freezing or Cooler Method. It works from the top-down. Now a reader has figured out a moderately easy way to freeze in a cooler from the bottom-up. 

An index to all of the ice experiments on Alcademics is here.

In the top-down method, one simply fills an insulated cooler with water and leaves the top off. The water freezes only from the top down, and all the trapped air and impurities are pushed to the bottom, where a cloudy 25% or so will form if you let it freeze that long. 

Freezing From The Bottom-Up

Commercial ice machines like the Clinebell freeze blocks of clear ice by freezing from a cold plate on the bottom, while a water pump near the surface keeps water circulating (thus preventing ice from forming on the surface). 

Reader Nome Park wrote me to tell me about a method he developed that sort of combines these two methods for the home user, producing a mini-Clinebell-type block. 

The cooler is insulated on all sides except for the bottom, and a small aquarium pump is used to keep water circulating at the top. 

The white area on the bottom is the interior of the cooler with the foam/plastic cut off so it's no longer insulated on the bottom.

Requires:

• A big freezer, like a horizontal freezer.
• A larger cooler. He uses a Coleman 20-can Party Stacker cooler, which is taller vertically and thus best for freezing bottom-up
• A small aquaium pump

Method:

1. Cut the cooler bottom outside layers off a few inches up from the bottom. Park did this using a Dremmel tool and a knife. *Important* You only want to cut off the outer plastic and the foam insulation. Do not cut out the interior plastic otherwise it will not hold water. 

2. Insulate the top lid. Park made a 2.5-inch thick piece of foam that fits snuggly inside the cooler (since the lids on these coolers tend not to be insulated. (Pump is just there for scale. It is not attached.)

3. Fill the cooler with water up to where the foam will hit it from the top. 

4. Hang the (unused for your fish tank) aquarium pump from the top, so that it's just beneath the surface of the water. Put the foam piece on top and the lid on that. Park cut a little section out for the pump power cord. 

5. Turn the pump on and wait for it to freeze. In Park's freezer, it takes  2 days and 2 hours to freeze (50 hours) into a block that isn't all the way frozen. If it goes too long (t 72 hours or so) the pump will freeze into the block and probably break.

6. Remove the cooler from the freezer, turn off the cord, turn the cooler upside-down, and wait for the block to slide out. (An hour is about normal). Now you're ready to cut it up. 

I asked Park if he tried this without the pump just to see what happens, but he had not tried it, basing his system on the Clinebell. 

So, for you ambitious sorts with large freezers, this might be a way to make larger blocks than with the small cooler at home. 

Thank you much to reader Nome Park who not only took the time to perfect this method but also to send me detailed description and pictures. 

Related articles

Behold the Glorious Index of Ice Experiments on Alcademics

How Water Freezes

Freezer Harvest: The New Ice Era on ModernFarmer.com

Another Way to Make Clear Ice at Home

Recently I posted a method of making perfectly clear ice balls using an insulated mug, which was sent in from Alcademics readers. 

The physics of the thing made perfect sense but I hadn't actually tried it myself at the time. This post is just to say that I use this method now and make nice round ice. Lots and lots of it.

The ice in the picture above isn't cloudy; just some of it is frosty on the outside. 

I use this stainless steel tumbler a small ice ball mold that it sits in. Easy. 

An index of all the ice experiments on Alcademics is here.