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Ice Cubes That Last Twice as Long

By Cook's Illustrated Published March 2012

Learn how to make restaurant-quality ice at home.

Why is it that the ice served by restaurants and bars can be sparkling clear—but the cubes you make at home are cloudy? The cloudiness in ice comes from dissolved gases and minerals. In an ice cube tray or home ice maker, water freezes from the outside in, pushing these impurities into the still-liquid center of each cube, where they eventually freeze, leaving an opaque, bubble-ridden core.            

Commercial ice machines first purify water with a built-in filtration system and then rapidly freeze it in progressive layers of ultra-thin sheets, a process that prevents air bubbles from becoming trapped in the cubes. The resulting translucent ice isn’t just for show: Its crystals are more tightly bound, so it melts more slowly, preventing waterlogged beverages.

You can make almost perfectly clear ice at home if you eliminate as many impurities as possible from the start. Use distilled water (which, unlike tap water, contains no minerals) and boil it for a few minutes to drive off dissolved gases before freezing it (there’s no need to cool down the water first). In our tests, the super-clear ice lasted about twice as long as regular cubes.

Done in 281 ms! 61.385 KiB - 7.5% = 56.776 KiB