Frozen-to-order ice cream

Given how much science goes into a single serving of yogurt or frozen custard at Sub Zero (427 Massachusetts Ave., 317-446-9247), you could expect employees to face a bit of a learning curve as they perfected the process. Clerks at the new Mass. Ave. shop, the latest location of the national chain, furrowed their brows as they kneaded the flavor bases (frozen almost instantly by a quick blast of liquid nitrogen) into something they could scoop into a paper cup. For the most part, the steady stream of customers dropping in for the shop’s inaugural days over the weekend seemed happy, ordering up custom flavor combos or suggested “Sensations” such as the Chocolate Conduction (sweet chocolate, fudge, chocolate shavings, and brownie bits) or the Birthday Cake Capacitor (cake batter, fudge, cookie dough, and sprinkles).

The relatively small, Utah-based franchise, which in nearly a decade has expanded to just over 30 stores in nine states, offers customers a bit more of an interactive experience to make it stand out from the glut of fro-yo and ice cream shops sweeping the country. Customers select a base (premium cream, low-fat, yogurt, almond milk, etc.), choose two base flavors and one “add-in” (additional flavors or add-ins cost extra), and wait for a quick chemistry experiment (and dramatic wisps of super-chilled fog) to transform their choices into something more recognizable as a frozen treat. The quick freezing, the company claims, means the liquid has less time to crystallize, making for a smoother texture.

A cup of black raspberry and cheesecake custard did seem as creamy as any we’d had lately, though the flavors weren’t especially intense. We enjoyed the crisp chunks of graham cracker crust we choose as an add-in almost as much as the custard. Whether the thrill of seeing the cream freeze before our eyes would wear off on subsequent visits, we weren’t sure. But we knew we’d be back to try one of the million or so other flavor combinations Sub Zero offers.