The Perfect Cube Silicone Ice Cube Tray
There is no substitute to using hand-made ice cubes. And the best cubes are made with food-grade silicone ice cube trays.
The solid cubes made with these trays begin as very, very hot spring water (boiled water which is left to cool for just a few minutes before pouring.) Fewer dissolved gasses, better convection currents necessary for even cooling, and a lower initial density all contribute to a fast freezing cube and a more perfect shape.
But more importantly, a half dozen solid cubes of ice in the proper cobbler shaker will deliver just the right quantity of melted ice water and ice chips for a perfect cosmo.