My oldest son asked me how to make clear ice. I was bit stumped. First, I thought our ice was clear until I took a closer look. The ice from our automated ice maker in the freezer was cloudy.
And then I found out that most ice made in homes are cloudy. Why? Typically, ice is made using tap water, which may contain contaminants, or automated ice makers (like what we had) that use cold, filtered water, which traps in air. In either case, ice comes out cloudy.
On the other hand, many commercial ice makers in restaurants produce clear ice due to the freezing process, which cools ice slowly on the way up – releasing trapped air. And many times water is filtered in these commercial ice makers.
So how can clear ice be made at home?
It’s pretty easy. Just boil water, let it cool for a minute or two, and then pour into ice cube trays.
Boiling helps to get rid of contaminants (see my post Could Your Ice Be Making You Sick? for more information) and trapped air. In the photo above, I boiled the water just once. Double-boiling can help even more.
Another option is using water purified from a reverse osmosis system. This removes impurities from the water – which help to make clear ice.
Give this a try at home. It was a fun experiment to do with my kids. And a good reminder to fill up our ice cubes with purified or boiled water to remove impurities.