Spring Water, Directional Freezing Yield Clearest Ice Cubes

According to a recent test conducted in the Kitchen and Cooking Lab, the key to making crystal-clear ice at home lies in a process called directional freezing, which was compared across various water types and freezing methods.

The test compared different types of water, including spring, distilled, tap, and boiled tap water, in both standard and directional freezing ice cube trays. While spring water produced the clearest results, both tap and boiled tap water were fairly clear, aside from a few bubbles and cracks. Only distilled water failed to come out perfectly clear, appearing filled with cracks running down the middle of the cube. All water types initially showed clear edges and cloudy centers in standard trays, but directional freezing significantly improved clarity.

Directional freezing involves freezing water from top to bottom, similar to how a lake freezes over in cold weather. This process allows any impurities or sediment to settle at the bottom, leaving the top portion of the ice clear. A directional freezing tray, with its excess space beneath the mold, facilitates this process, enabling the creation of perfectly clear ice cubes. The design ensures that sediment has room to settle away from the final ice cube.

After freezing the ice cubes overnight in both standard and directional trays, testers compared them at various intervals: immediately after removing from the mold, five minutes after removing, ten minutes after removing, and finally, 15 minutes after removing. This detailed comparison highlighted the superior clarity of spring water in directional freezing trays and the consistent failure of distilled water to produce clear ice. Testers also noted that while there was no discernible difference in taste between clear and cloudy ice, drinks with directional freezing tray cubes tasted stronger.