“How do I make really clear ice cubes?”
It may not surprise you that this is one of the most frequent questions asked by people who’ve just learned that I work with ice. I do worry about making clear ice – a clear ice sample is devoid of gas bubbles and cracks, which can interfere with the processes I’m trying to study – but I also attach my samples to a vacuum pump to draw air out of them, and smash them at 1000x atmospheric pressure to press out even the tiniest bits of gas that still remain. This is not exactly a practical method of getting ice cubes for a drink!
Yet fear not, ye who need beautiful ice cubes: David Rees, on his National Geographic show “Going Deep,” answers the question of the perfect ice cube in extreme, yet enlightened, detail. Do you suffer from unsatisfying, refrigerator-produced ice “cubes” that “aren’t even cubes, they’re shaped like slugs…and sometimes taste like onions”? Then read on for the Cliff’s Notes version, or skip to the link and watch David’s far more entertaining description!
- Start with clean, but mineral-rich, water. Clean water makes clearer cubes, but minerals make the cubes taste good! If you don’t have distilled water, boil your water to clean it of bacteria and get rid of dissolved gasses.
- Carefully pour the water into a deep tray. Allow it to cool to room temperature.
- Put the tray in your freezer. The water will freeze from the edges inward, forcing any remaining air into bubbles in the center of the dish. This is why you need a deep dish!
- Once frozen, break the clear edges away from the bubbly interior (the video clip shows you how to do this nicely).
- Clean up the edges of your cubes by pressing them against a warm, flat piece of metal (like a metal cookie sheet). The metal doesn’t have to be very hot – you can warm it up by running it under hot water from your tap.
- Voila, pretty ice!
Here’s the link to the video: http://www.hulu.com/watch/669146#i0,p0,d0