Here’s an easy method to make clear ice balls for soft drinks, cocktails, or a whiskey/rocks glass. One ball will keep a drink cool for at least 60 minutes, with minimal dilution compared to ice cubes of equal volume. Plus, it looks incredible in the glass.
The secret is directional freezing — cooling the water in such a way that any air bubbles are pushed out of the ball mold before it fully forms into ice. Normally, ice freezes from the outside in, forcing unseen air bubbles inward until they collect and cloud up in the center. Adding an insulated container, however, provides a reservoir of water that freezes slower than that in the non-insulated mold. This lets the freezing begin at the top of the mold and move downward, pushing air bubbles out into the reservoir instead of trapping them. The result? Crystal clear ice! (Find more on this process by its pioneer, Craig Belon, on the Alcademics site.)