How to make fluffs & foams

Ever since Ferran Adria of El Bulli took his batterie de cuisine into the laboratory, we've been seeing as much smoke and foam on our fine-dining plates and upscale cocktails as Hollywood's adventure and horror movies offer. And we've been just as pinned to our seats and bar stools by the experience, only without the screaming. The secret to the smoke is liquid nitrogen. But how about the foam?

Liquid nitrogen can be bought on the internet. But only in such large quantities they make no sense to the home cook. And it shouldn't for safety reasons, given it comes in a pressured cylinder not unlike a fire extinguisher, be in the hands of a novice. Besides, producing smokes at home rather spoils the fun of going out and watching someone else go to all the trouble. Foams, on the other hand, are cheap, accessible - and simple to manipulate. Soy lecithin is the secret, and Whole Foods sells it, in granular and liquid form at under $10 depending on quantity.

To make a salt foam like the one fluffing the margarita in the photograph, in a blender add 1 part fresh lime juice to 2 parts water and 1 tablespoon of fine salt. Cover with the lid, having removed the central plug. Start whizzing to liquify the salt then pour soy lecithin in small amounts little by little through the hole until you can see it take, creating a fluff that should survive around 3 hours before subsiding. Spoon over freshly-made margaritas.