Long sleeves. Check. Goggles. Check. Safety gloves. Check.
Liquid nitrogen hisses and boils violently as it's poured into the bowl of a stand mixer, erupting into a 360-degree wave of vapour that ripples through the room. When the fog clears, it has transformed a vanilla custard into the silkiest ice cream imaginable, all in the confines of a home kitchen.
Molecular gastronomy chefs first recognized liquid nitrogen's potential to create stellar ice cream years ago. Michelin three-star wunderkind Heston Blumenthal of The Fat Duck in Bray, England, has a famous bacon-and-egg variety. In Canada, servers craft dishes of liquid nitrogen crème fraîche ice cream tableside at Toronto's Colborne Lane.
But while many molecular gastronomy innovations never migrate beyond professional kitchens, this is one technique resourceful cooks can use at home. And it's not just for show. Liquid nitrogen enhances one of ice cream's signature qualities: texture. "People are looking for creaminess," says David Lebovitz, a veteran of the pastry department at the legendary Chez Panisse and author of The Perfect Scoop: Ice Creams, Sorbets, Granitas, and Sweet Accompaniments.
Taste is still paramount - people ceaselessly bicker about the superiority of one flavour over another. But chocoholics and vanilla junkies almost unanimously prefer ice cream that has a smooth consistency and rich mouth feel even after the carton has been pulled from the freezer a dozen times. That's why most store-bought ice creams contain a long list of unpronounceable emulsifiers and stabilizers such as mono- and diglycerides, guar gum and carrageenan.
It wasn't always so. Back when ice cream was a down-home affair made with ice, salt and elbow grease, a little coarseness was expected, even appreciated. But with industrialization came palates that craved ever-more-refined results. "Dense," "smooth" and "creamy" became buzzwords for this ideal texture.
Of course, this emphasis on texture gave mass producers, with their specialized additives and blast freezers, an advantage over home kitchens equipped with only basic ingredients and chill chests set to a relatively balmy -18 C.
Liquid nitrogen not only levels the playing field - it tilts it in the home cook's favour. At the microscopic level, ice cream is ice crystals surrounded by chilled cream and air. Small crystals equal smooth ice cream, and they require rapid freezing. That means mind-bogglingly cold temperatures.
Enter liquid nitrogen.
As noted food science writer Harold McGee, author of On Food and Cooking: The Science and Lore of the Kitchen, explains: At -196 C, the temperature of liquid nitrogen, "water molecules are essentially frozen in place and end up being immobilized in tiny aggregates, mini-crystals, and so you get this wonderful creamy effect."
It may sound extreme, but making liquid nitrogen ice cream differs very little from the traditional ice-cream-making process familiar to home cooks. The base is exactly the same - a blend of dairy, sugar and sometimes eggs, with a flavouring - but it's frozen by slowly stirring liquid nitrogen into it using either the paddle attachment of an electric stand mixer or a wooden spoon and some muscle.
The result? Liquid nitrogen produces "unequivocally the best ice cream I've ever had," says chef Claudio Aprile of Colborne Lane. It's a position he defends by pointing to his work with scientists who have "PhDs in ice cream technology" - and objective experience.
"Do a blind taste test," he argues, "and let it be the deciding factor." Then he brandishes a bowl of lemon-zest-dappled crème fraîche ice cream - fashioned à la minute with some liquid nitrogen and a wooden spoon - that melts into a silky ribbon on the palate.
All that creaminess comes at a cost: Renting the dewar (the thermos on steroids in which liquid nitrogen must be stored) and buying five to 10 litres of liquid nitrogen (the minimum amount most vendors will sell) runs from $50 to $100, plus deposit.
