When Is It Safe to Use Liquid Nitrogen in Cocktails?
The news of an 18-year-old losing part of her stomach after ingesting a liquid nitrogen cocktail made us all a little queasy. Now that the U.K. government is seeking to ban liquid nitrogen from all drinks, we wanted to understand how liquid nitrogen could be used safely.
Enter Scott Heimendinger, part of Nathan Myhrvold's Modernist Cuisine team. As the director of applied research for Modernist Cuisine (and the man behind Seattle Food Geek), Heimendinger is no stranger to using liquid nitrogen. Here, he shares with The Daily Meal the dangers of liquid nitrogen, what might have caused the teenager's horrific reaction, and how to use liquid nitrogen safely.
The Daily Meal: What kinds of cocktails use liquid nitrogen? What kind of effect does liquid nitrogen produce in a drink — besides the aesthetics of the smoke?
Scott Heimendinger: Generally speaking, liquid nitrogen is used as a way to make things cold, quickly. At standard atmospheric pressure, liquid nitrogen boils at -321 degrees F, so it is extremely cold. When it heats above that temperature, it evaporates into gas. For that reason, you wouldn’t actually want to drink liquid nitrogen, as it may cause injury at that temperature. Instead, you can use small amounts of liquid nitrogen to chill other liquids rapidly. Incidentally, the "smoke" is actually a miniature cloud produced where cold nitrogen gas causes water vapor in the air to condense into tiny droplets.
TDM: What dishes does Modernist Cuisine use liquid nitrogen for?
SH: We use liquid nitrogen for several techniques. In cryofrying, we dunk food (steaks, burgers) into liquid nitrogen for a short time (30 to 60 seconds or so) before deep-frying them. This shock of cold protects the interior of the food from overcooking while the surface browns in the hot frying oil. We cryoshatter some foods (cheeses, oils) by freezing them solid in liquid nitrogen and then whacking them with a mallet. They shatter into shards. This techniques works particularly well for breaking raspberries, blackberries, and pomelos apart into individual drupelets or juice sacs. We also use liquid nitrogen to freeze delicate herbs before grinding them into cryopowder; the herbs don’t bruise when crushed this way. Additionally, we use a technique called cryopoaching, in which we chill or freeze just the outside of a food so that the interior remains soft or liquid. For example, we make "cryopoached meringues" that are lightly frozen on the outside, but give way to a foamy center. The entire "meringue" melts in your mouth. Foams can be safely served in this manner because they have very low density. However, most solid foods should never be served at or near the temperature of liquid nitrogen; they must be warmed first.
TDM: Is the biggest danger of consuming liquid nitrogen the temperature, as the Food Safety Agency warns?
SH: Yes, certainly. In the very same way, the biggest danger of frying oil is its high temperature.
TDM: What are the safety precautions mixologists (and chefs) must take to use liquid nitrogen safely?
SH: Use cold-safe gloves and long pants (that cover the tops of your shoes) when handling containers of liquid nitrogen. Avoid skin contact with liquid nitrogen directly, and especially with containers or tools that are in contact with liquid nitrogen — the extreme cold may cause skin damage. Also, do not store or use liquid nitrogen in poorly ventilated areas. As it evaporates, nitrogen can replace the air in an enclosed space and cause asphyxia without warning. Also for this reason, do not transport liquid nitrogen in the cabin of your car — in fact, transporting liquid nitrogen is restricted in many areas, so consult your state Department of Labor office for complete regulations.
TDM: What are some of the safety hazards of consuming liquid nitrogen in drinks and food?
SH: Don’t ever consume it as a liquid. Just as you wouldn’t eat a french fry straight out of hot oil, or worse yet, a spoonful of hot frying oil, foods that have recently come into contact with liquid nitrogen will be extremely cold. Do not consume or touch foods at extremely cold temperatures or you may risk skin damage or internal injury.
TDM: How can using liquid nitrogen go wrong — and what could have been the reason the girl had to have her stomach removed?
SH: The hot frying oil analogy applies here as well. You can burn yourself from extreme cold just as you can from extreme hot.
TDM: Does liquid nitrogen have different effects on different people? (Because reports say the girl’s friends had the same drink but didn’t experience any negative effects.)
SH: No. Nitrogen, in gas form, comprises 78 percent of the Earth’s atmosphere. So, we’re all exposed to nitrogen all the time. I cannot say why her friends didn’t have the same reaction without speculating, but in all likelihood, this particular girl’s drink was prepared improperly, or served when there was still liquid nitrogen present.
TDM: Should consumers avoid using liquid nitrogen in their homes? Are there any precautions they should take before using it in food and drink?
SH: Although liquid nitrogen is popular among hobbyists, it must be handled with great care to avoid injury. Do not transport or handle liquid nitrogen without proper safety training and equipment.