A large number of people have become interested in clear ice. The best way to answer the clear ice question is to think about icicles.
If you live in an area where icicles form in the winter, you know that icicles are normally clear and beautiful. There are two things that make icicles so perfect:
- Icicles are made from pure water in the form of melted snow.
- Icicles are created in layers. Water drips down the icicle and freezes in progressive layers rather than freezing all at once. This approach avoids entrapped bubbles.
If you ever look inside a restaurant ice maker, you will find that it makes ice in layers. Cold water runs continuously over a plate or a grid where the ice is forming, and the ice cubes (or ice disks in some machines) grow in layers.
If you would like to try creating clear ice at home, start with distilled water (to eliminate the minerals) and boil it (to eliminate air dissolved in the water). Make the cubes small or thin to get closer to the way that icicles are formed.
Robert Fulghum adds the following: