Liquid Nitrogen

Nitrogen is one of the most abundant elements in the Earth's atmosphere. The air we breathe is almost 80% nitrogen, a colorless, odorless and tasteless gas. Despite its abundance, its use in cooking is a relatively new development. But it has spectacular results.

The pioneer in experimenting with this amazing culinary technique was the French physicist and chemist Hervé This in the mid-nineties, followed by the chefs Heston Blumenthal and Ferran Adrià, who opened up new avenues that led to its widespread use today.

In cooking, nitrogen is used in its liquid state, characterized by a temperature of -196ºC / -320ºF, which means that everything it touches "freezes" instantly.

What is needed?

You need a specially designed recipient for liquids at low temperatures, usually made from stainless steel to prevent breakages and with an inside coating of cork or Teflon to minimize evaporation. Apart from this, handling involves a series of special measures, such as heavy gloves and keeping contact time to a minimum.

The only special precaution required is that it must be used in well-ventilated areas and must never be mixed with other liquids except under controlled conditions.   

What is its culinary use? With liquid nitrogen you get almost instant freezing for any product it comes into contact with. The cold has a similar effect on food as heating, removing the liquid content.  This means that it not only changes the original appearance of food, but also its texture, so you can obtain powdered oil, for example, or frozen foams.

It also enables you to play with temperature contrasts so you can serve a dish in which the inside ingredient is cooked and kept at its ideal eating temperature, while the outside is completely frozen.

Another use is for obtaining a liquid at room temperature separated from the outside by a thin film, or for making ice-cream by freezing the creamy base instantly.

Its produces better results with products that have a higher fat content, but the results are less eye-catching on foods with a higher water content.

What are the benefits?

Apart from its creative potential in cooking, the liquid nitrogen technique can also speed up cooking times by eliminating any bacterial growth or freeze fluids with minimum ice crystal formation. It also freezes foods that cannot be frozen in a normal freezer cabinet (where the temperature only drops to about -32ºC) and also products with a high alcohol content.

Its application enables new cocktails to be invented, involving new sensations, such as the so-called "dragon effect", in which the vaporized nitrogen swallowed comes out of the drinker's nose, with striking results.

Paco Roncero is head chef of La Terraza del Casino restaurant (Madrid)

Modern Cooking Techniques: Liquid Nitrogen