321 Degrees below 0

 

     What boils at a temperature of -321 degrees F? Liquid Nitrogen of course. As a result of it's extremely cold properties many chefs are able to do things that were deemed to be impossible or even unimaginable in years past. The integration of liquid nitrogen into the realm of culinary arts has created even more techniques than Escoffier himself could have ever dreamed about. The techniques all start with the prefix Cryo, which denotes the utilization of liquid nitrogen in the technique. The techniques are as follows;

Cryoshucking: mussels and clams that are submerged in liquid nitrogen are easier to open.
Cryocracking: nuts that are submerged in liquid nitrogen are easier to crack.
Cryogrinding: nuts, seeds, and grains that are submerged in liquid nitrogen are easier to mill into flour.
Cryograting: used to freeze a soft item solid so that it can be easily grated
                       (steak, bananas, mushrooms).
Cryopowdering: used to powder vegetables, herbs, or flower petals without turning them into paste.
Cryoshaving: used to get paper thin shavings off a soft item such as prosciutto.
Cryoshattering: used to break apart berries, citrus fruits soft cheeses, or just about anything you desire  
                            to get random size shards of that items or in the case of the berries and citrus  
                            individual compartments.
Cryopoaching: used to form a thin frozen shell on a food item.
Cryosearing: used after a product has been cooked sous vide. The food item's exterior is quickly
                       frozen, so that the internal temperature stays at it's desired doneness while the outside is
                       seared on a hot surface till crispy.
Cryofrying:   used after a product has been cooked sous vide. The food item's exterior is quickly
                       frozen, so that the internal temperature stays at it's desired doneness while the product is
                       submerged in hot oil in order to crisp the outer surface.
Cryoforming: used to make sorbets, ice creams, frozen meringue, or frozen custards. Creates a
                        smoother product, since the ice crystals stay very small as a result of the quick freeze.
Cryoblanching: used to add texture to vegetables as well as retain their color and keep them fresh
                            longer.

(dippin' dots are made through Cryoforming)

    When using liquid nitrogen it is imperative to take extreme caution with all metal surfaces. Any metal surface that has come into contact with the frosty liquid can inflict nasty frostbite within seconds of touching the surface. Take precautions by wearing protective cryogloves or by running warm water over any frosted surfaces, which includes spoons as well. All cryofrozen food items need to be thawed out in a freezer or refrigerator before they are consumed to avoid any frost bite to the mouth or throat of the patron consuming the food item. No liquid nitrogen should be ingested directly as this could cause injury to the individual. Direct contact with an impermeable convex surface will cause the Leidenfrost effect, which means that liquid nitrogen droplets that come in direct contact with human skin will not inflict any damage. 

The Leidenfrost effect is caused by the temperature differential between the liquid nitrogen and the air around it. The liquid nitrogen will bounce along on a layer of gas which protects the surface from actual direct contact with the substance itself. A hand quickly submerged into liquid nitrogen will not be injured thanks to the Leidenfrost effect, don't try that with fryer oil.