Churn2 in the Harvard University Science Center serves made-to-order liquid-nitrogen ice cream from a gussied up semi-permanent shipping container. Liquid nitrogen is the new craze in frozen desserts. The appeal is that it allows owner Ash Chan and his team to make fresh ice cream instantly in an industrial mixer. He vigorously mixes liquid nitrogen with an ice cream base; the nitrogen freezes the ingredients instantly. A minute later, you have ice cream ($5.25 to $6.25 for 4 to 4.5 ounces). The scene attracts attention — the mixture emits smoky vapors — and the process eliminates freezers. Raised in Boston, Chan owns three shabu-shabu restaurants in California (he divides his time between East and West coasts). He was researching more cost-effective business models and discovered shipping container restaurants. “Technically we are a food truck, because we are mobile,” says the entrepreneur, who will be open until Oct 25. Unlike trucks, however, he can get deliveries. Chan and his team are mixing maple-bacon ice cream, caramel-apple, strawberry-banana, and mint chocolate-chip. If this succeeds, the ice cream maker plans other innovative projects, all inside shipping containers. Churn2, Harvard University Science Center Plaza, 1 Oxford St. (Harvard Square), Cambridge, or go to churn2.com.