Grant Crilly is the Executive Director and cofounder of ChefSteps. Grant is a classically trained chef and, prior to ChefSteps, he worked on the award-winning cookbook series Modernist Cuisine and cooked at various restaurants, including L’Astrance in Paris, Busaba in Mumbai, and Mistral Kitchen in Seattle.

Grant Crilly

Imagine glacier ice cubes—zero bubbles, zero cracks, so clear they become invisible in the glass—floating in your cocktail. How? It’s simple. All you need is a small insulated cooler and water. Let’s go! This summer, Grant ended up 2,300 miles away from Seattle, on a sailboat in Alaska with his family. Grant’s father-in-law took small chunks off a glacier to make cocktails. This meant the family drank Manhattans with 100,000-year-old glacier ice. The flavor of the drink didn’t change, but the ice looked like diamonds floating in the glass. Drinking that glacial cocktail made Grant think of all the interesting twists we’ve done at ChefSteps before: making an ice shell with liquid nitrogen, creating lemon granita, and turning granita into snow. And yet, somehow, he realized, we haven’t shared how to make crystal-clear ice before. Why do ice cubes made in trays come out cloudy? The water is freezing from all directions: below, from all the sides, and the top. That means the ice forms a solid shell from the outside, with icy water in the middle. Problem is, water expands by 9% as it freezes. That means that as the inside freezes, there’s nowhere for it to go. It cracks. It bubbles. It fissures. Cloudy ice cubes. Glaciers, however—and lakes—stay clear because they freeze only from the top down. Without freeze happening from all sides, ice cubes could be clear too. How do we create a glacier at home? Buy a cooler with thick insulated sides, (or get an old Coleman from the thrift store.) Fill it with water. Let it freeze for 24 to 48 hours. And the rest? Well, just watch.

A Little Bit of Glacier in Your Glass