As a general rule, bigger is better—and also: Balls are better than cubes. The reasoning: Less surface area means less dilution. In other words, a single sphere of ice will melt more slowly than smaller, rectangular cubes, so your drink will stay stronger longer. Japanese bartenders make their ice spheres by hand, but you can make your own with the Original Whiskey Ball.
So does water.
Water impurities are an easy way to undermine your otherwise perfectly crafted cocktail. Any water—even if you’re getting it from Icelandic lava fields—will give you cloudy ice, unless you’re freezing it in a Clinebell machine, explains Daniel Brancusi, formerly of Vitae, now the brand ambassador for Reyka Vodka. Still, that doesn’t mean you should use tap water. Use a water filter, like Soma’s streamlined carafe and make sure your freezer is very clean.
Cool before you pour.
Regardless of whether you’re using spherical ice or cubes, big balls or tiny pebbles, you can slow down the melting process by shaking your cocktail with ice before pouring it over ice. Cold over cold means a more languid dilution.
Cater to your cocktail.
Certain cocktails—swizzles, for example—call for ice pebbles (or, in the case of mint juleps, crusted ice) to bring down the temperature and dilute the drink. The next level of cocktail-specific ice? Collins cubes. These long, rectangular rocks are made specifically for a tall Collins glass. Another step up, says Brancusi, is ice made out of iced tea, fruit juice, and anything without a high alcohol content. “It’s a fun way to add additional flavors through ice.”