Liquid nitrogen has become a culinary tool in recent years, as its extremely cold properties can both freeze food and send off Instagram-worthy smokelike gas. It carries risks, though, including frostbite and/or bodily harm if ingested, owing to its aforementioned extremely cold temperature. That’s why health officials last year issued a warning about “Dragon’s Breath” ice cream, which is made with liquid nitrogen. The liquid nitrogen, if eaten accidentally, could “cause severe damage to the mouth, esophagus and stomach.” One Florida woman claims liquid nitrogen did just that after a hotel in St. Pete Beach, Florida allegedly spiked her water with the substance.
News reports state the woman was celebrating her November birthday at the Don CeSar hotel, where a waiter added a liquid nitrogen component to a dessert. She and her friends remarked on how intriguing the visual effect was. The woman alleges a bartender then added that liquid nitrogen to her and her friends’ water glasses; after drinking from hers, she had to be admitted to the hospital and suffered the removal of her gallbladder and a portion of her stomach. She is, as a result, suing the hotel.
What happened to this woman is undeniably sad. But, you’re not the only ones to wonder whether there wouldn’t have been some clue that the drinks had had liquid nitrogen added to them. (Perhaps she drank it anyway, assuming the hotel wouldn’t serve her anything dangerous.) My favorite food safety website, barfblog, written by a former professor of food safety, raises one simple question in its post about this incident: “Except, wouldn’t [liquid nitrogen] immediately freeze the water?”
I myself had questions about the logistics of liquid nitrogen and its reaction with liquids. I emailed my dad, a former research chemist, an article about the woman’s lawsuit to hear his thoughts. (When I was a kid, my dad sometimes conducted small experiments with dry ice, liquid nitrogen, etc. to get my brother and I interested in science; the liquid-nitrogen-frozen-banana hammer was a favorite of ours.) I wanted to know what he thought of this whole incident.
He tells me that liquid nitrogen and dry ice “smoke” due to the Leidenfrost effect, which means both “boil” so rapidly that the liquid nitrogen or solid carbon dioxide surrounds surfaces with an insulating layer of gas. A small amount of liquid nitrogen dropped into a liquid will rapidly boil away and no longer pose a freezing danger. Larger amount of liquid nitrogen could pose a risk but would, in my dad’s poetic words, “boil like a witch’s brew,” which he correctly states would discourage most people from drinking it. He says he “would welcome a scientific outcome and rational explanation” for this story. Ditto.
While we await actual testimony in this case—unless it settles before trial—we can draw at least one important conclusion at this juncture: Liquid nitrogen is dangerous to ingest, and all smoking/fogging/sublimating food or beverages should be treated with extreme caution.