Restaurants and bars use professional filtration systems to create clear, long lasting ice — freezing water quickly to prevent bubbles. Clear ice “isn’t just for show: Its crystals are more tightly bound. So it melts more slowly, preventing waterlogged beverages.”
When we make ice at home, especially in standard fridge/ freezer systems, ice freezes from the outside in and clouds with minerals and trapped bubbles. But you can make pure, great-drinks ice too if you use DISTILLED WATER which, unlike tap water, contains no minerals. If you choose to boil the water first for a few seconds, bully for you! That’s even better to dissolve gases before freezing.
Any way you crunch it, super-clear ice lasts twice as long as regular cubes. And drinks taste better!
— adapted from Cook’s Illustrated (March & April 2012)