Author: Camper English

Here's an interesting problem and solution: James Hogarth reached out to me to describe the following. He is using water filtered with a Zero Water filter in a clear ice system. This filter removes all the major dissolved solids in the water, and it comes with a little TDS meter to verify it. But the supposed-to-be-clear ice that comes out from this water has streaks remaining, but regular tap water doesn't. 

My tap water has a terrible taste, however, when I freeze tap water [in the Wintersmith’s Phantom] it does freeze perfectly clear. The bad news is that if I then thaw the water it still retains a bad taste. It is improved but still not good.

Curiously, the ZeroWater filter comes with a Total Dissolved Solids meter, and while not the most sophisticated meter in the world, it reads around 110-120 on tap water and perfect 0 for the thawed water. 

So right now I either get great tasting ice with air bubble streaks, or perfectly clear ice that tastes terrible.

Even distilled water gave me streaks of air bubbles. My freezer was always right around 0 degrees, and multiple different molds, no mater what, boiled or not, still got streaks.

He theorized that his water was actually freezing too fast without salt and other minerals in it that would naturally slow the rate of freezing. 

So to test the theory, he tried adding table salt to TDS 0 water – and it was successful! He added a concentrated salt solution to the rest of the water to try to bring it around 135 ppm before freezing. 

I know that ice crystals will push out salt molecules as the ice crystalline structure does not have room for it. Freezing water is one method for desalination of sea water for this reason, it just isn’t very energy efficient.

The melted ice tastes just as good as the filtered water. From the top half [the clear part], the meter reads 6 and the bottom half 163.

So after a few more batches of ice, and a few bottles of whiskey, it seems that around 140-180 ppm of table salt in the ZeroWater is ideal. I get crystal clear ice, and when I melt the ice and test it, it’s usually 6ppm salt or less.

We knew that freezing water pushes the trapped air and impurities (including the minerals) to the last part of ice to freeze. What's interesting here is that at least in this case, the presence of "impurities" while freezing seems to improve the clarity of the ice, and we can theorize that is because they slow the rate of freezing. 

Hogarth later tried other minerals, including mineral drops that are sold to supposedly make water healthier. He found they acted in much the same way, concentrating in the cloudy part of the ice. 

Trace Mineral Drops: starting at 204 ppm, melts to 23 ppm. So something is clearly less filtered from directional freezing than salt or calcium chloride. Both of which could be as high as 240-250 ppm and the melted ice would be around 6ppm. I don’t have the tools to tell you what it is though.

 

So I'll leave this at that. To replicate it, I (or better yet, you) could try freezing two identical quantities of water in identically-shaped insulated trays: one with TDS 0 and one with some dissolved solids.

This might not be an issue if your freezer temperature is higher and closer to the freezing point, but most freezers have maximum temperatures much lower than that for food safety. 

Ice with Streaks

I have several ways to make ice spheres at home, but the one that takes up the least amount of space is using a thermos and ice ball mold. 

This method produces nice large ice spheres but they're not as smooth and perfect as those made in the IceOlogy trays or big cubes pressed into spheres using an ice ball press. 

So I thought I would try using the ice ball press to smooth off the surfaces of ice balls made in the thermos method. It works only just okay – because the ice ball press makes larger spheres than the ice ball molds I have. They come out a little odd shaped as the fit is not perfect. A better size match would be better.  

Lately I've been making designs on ice cubes using the Ice Designer tool or these Cookie Stamps. I even wrote a story about how Patterned Ice Conquered Drinkstagram. 

Well in my fairly regular perusal of Amazon for new ice stuff I came across these stamps that are used to impress patterns into clay and other materials. I thought they just might make cool patterns in ice cubes, and surprise, surprise – I was right!

The first step is to make clear ice in one of the many ways demonstrated in my ice experiments.

I first tried them at room temperature and the pattern didn't go deep enough. Then I heated them up a bit – atop my toaster actually. Then pressed the ice on them. It worked great! 

As you know, I make ice in an insulated cooler in the process known as directional freezing first demonstrated here on Alcademics in 2009.

Lately I've been playing with an ice sphere press to make super nice looking ice balls.

But the problem is that the ice spheres are about 2.7 inches in diameter and there is no 3-inch ice cube tray that I know of. In order to make roughly 3-inch cubes, I make a whole cooler full of clear ice and then cut it up to the size that will fit in the ice ball press. Cutting up a slab of clear ice into these shapes isn't that much of a hassle, but still I am lazy and want to find a better way. 

So I decided to hang dividers in my cooler that would make the ice easily break into sections. This is a work in progress. I first tried one thick plexiglass divider that didn't fit across flat. It was really hard to get the ice out of the cooler afterward, and I figured out that it works best when you can see all the edges of the plastic. But anyway it worked.

Next I experimented with a thick plastic sheet I purchased from Tap Plastics, and then cut to size. It works best when the plastic is straight across the cooler, rather than curved.

Then I realized the defrosting plate that I use to smooth the edges of ice actually fits flat across the width of the cooler. It actually slides right into the grooves in the cooler. Unfortunately, this defrost plate is no longer offered online, so I've been experimenting with others. I'll let you know if I find another one that fits perfectly.

In any case, the metal plate slides out of the ice easier than plastic does. I also learned that it's far easier to separate the block from the dividers if I don't let the block freeze for more than two days, which gives me about 3 inches of ice in the cooler. 

Not that I have three sections of ice instead of one block, I can cut each slab in half to get roughly 3-inch cubes just like I wanted. It's a start! 

Anyway, I'll keep you posted on the progress of this project. 

As you're probably aware, patterned ice is the new logo ice. 

You can make patterned ice with an ice designer ($160) or a meat tenderizer ($13), and recently I purchased some cookie stamps ($27) to give those a try. 

The round shape can be limiting, but they're pretty large and will cover a 2" cube. A new addition to my icy arsenal. 

Check out all my recommended ice tools at this page, and all my ice experiments at the Ice Index Page.