The white stuff in your ice cubes is actually very very tiny air bubbles.

Virtually all-natural water you deal with is oxygenated to some extent. It’s why fish can breathe in it. Scientists measure dissolved oxygen in streams to determine how healthy the environment is. And when the water flows from your tap, it tends to be pretty well-oxygenated also.

As the water freezes, it wants to form a regular crystalline structure (ice). That means impurities like oxygen and other dissolved gasses are pushed away from the crystallization…