One difficulty with the Igloo Cooler method of making clear ice is that you get a great big block of ice at the end and have to cut it up into usable cubes yourself. I developed an ice cube tray using plastic boxes that gets the ice into long rectangles, and that's a bit closer to ideal.
But if the desired result is round clear ice balls, we need to either produce a mold that fits inside the cooler, or else carve out ice balls afterwards.
Well, it turns out that someone produced such a mold to make clear ice balls one at a time, using the same principles as the Igloo cooler method.
Alcademics reader Todd pointed me to this ebay listing for a clear ice ball maker from Japan.
As you can see, it's an insulted tube that holds a circular ice ball mold inside of it, along with extra space below the ice ball.
The important thing to note is that the ball mold is perforated. This allows any air and impurities in the water to get pushed out of it, towards the bottom of the mold, as it freezes. In other posts here on Alcademics, we've discussed that's how you'd need to build the mold in order for it to work.
It only makes one at a time, but it's pretty cool. The only not cool thing about is is the price: It's for sale at $97.60 each!
I still kinda want one.