The other day, I found a reason (as one does) to consult "Dreams: Hidden Meanings and Secrets," a guide to the unconscious mind first published in the 1940s. "To drink tomato juice," reads one entry, "predicts travel by airplane."
Sure, that makes sense. Many of us associate tomato juice with airplanes. Consider the following statistic, drawn from the data of my own life: In the past year, I've consumed at least half a dozen cans of tomato juice while cruising at 35,000 feet, and zero cans of tomato juice while at any other altitude. Here's another: According to Lufthansa, more tomato juice is served in-flight, gallon-wise, than beer. Meanwhile, on terra firma U.S.A., beer sales are several orders of magnitude larger than tomato juice sales. (We buy about as much tomato juice in this country as Keystone Light.)
Clearly I'm not the only member of the Mile High Tomato Club. But why is tomato juice so popular in-flight?
Consult the Internet, and you'll find a reference to a 2010 study by Lufthansa, in which researchers tried to recreate the conditions of an in-flight meal so they could test how airplanes might affect a person's sense of taste. The study found that changes in air pressure could mess with sweet and salty signals to the brain, shrinking those sensations by up to 30%. That confirmed earlier research, dating to the early 1970s, which led airlines to serve honey-roasted peanuts. Their thinking went like this: Give the people extra-sweet and extra-salty snacks, and you can overload their unresponsive tongues. From there, it's just a short step to tomato juice, a sweet and salty drink.
Another line of research looked at noise instead of pressure. In April 2015, Cornell taste physiologist Robin Dando published findings from a study in which he presented volunteers with each of the five fundamental flavors — sweet, salty, bitter, sour and the meaty-savory flavor called "umami"— as they listened to loud recordings of airplane-cabin noise. Their sweet perception was diminished, Dando's group discovered, while their taste for umami went the other way. Since tomato juice has lots of umami, that might explain why people prefer it on planes: It's among the only beverages that could have its major taste enhanced in flight.
Taken as a whole, these findings are a bit confusing. Do people crave flavors they can't taste well on planes, like sweet and salty? Or those they taste especially well, like umami?
Both science-based accounts also point to a strange (and suspicious) conclusion: Tomato juice, as it's been formulated for consumption on the ground, has its flavors misaligned.
Mass-market food products are engineered with great precision, such that their tastes converge on "bliss points" — the specific levels of saltiness, sweetness and other flavors that create the most perfect, pleasurable response. But according to the scientific theory of the Mile High Tomato Club, this process must have gone astray. When it came to manufacturing tomato juice, Big Food engineers either added too much salt and sweet, or not enough umami; they somehow found a way to miss the bliss. Only on airplanes is their drink fully optimized for human consumption.
If that were true, why wouldn't the manufacturers dial up the sweetness of tomato juice, or dial down its umami, for the much bigger market of consumers on planet Earth?
Perhaps all these data serve as props for just-so stories: science-y assertions adduced in retrospect to rationalize what would otherwise be seen as an artifact of history and culture. Why do girls tend to like the color pink? The just-so science story says it's because girls evolved to scan for berries in the bush (and not because an arbitrary gender code has been passed down from one generation to the next).
Maybe the in-flight popularity of a usually overlooked drink has less to do with taste buds than with the intersecting histories of tomato juice and aviation.
Tomato juice was rarely served until the 1920s, according to historian Andrew F. Smith. A pair of brothers in Indiana repurposed a machine used for making ice cream so they could turn tomato pulp into a thick, palatable beverage. The H.J. Heinz and Campbell Soup companies adopted the idea and started mass-producing tomato juice. Welch's, which had worked only with grapes up until that point, got into tomato juice in 1927. At the end of Prohibition, in 1933, the inventor of the Bloody Mary brought his cocktail to the U.S., and 8 million cans of tomato juice were sold in 1935.
More to the point, the craze for tomato juice coincided with the rise of commercial aviation. The first, full-blown in-flight meal service arrived in 1927, and the custom grew from there with the rapid growth of transcontinental flights. Could the timing of these two innovations have been the seed that turned into a culinary custom?
Or maybe it had to do with the power of celebrity. Among the most important early evangelists — and paid spokespeople — for the airlines was the famous pilot Amelia Earhart. And guess what Earhart liked to drink when she went on flights?
"Tomato juice is my favorite working beverage — and food too," she said in an episode of the radio program Heinz Magazine of the Air, sponsored by a tomato-juice manufacturer and broadcast in the fall of 1936.
A newspaper story published that same year described Earhart as having embarked on a study of "aerial dietetics." Her favorite foods were hard-boiled eggs, raisins, chocolate and cans of what she called her "all-reliable tomato juice," which could be had either hot or cold, opened with an ice pick and sipped through a straw. Her containers of tomato juice would appear in numerous accounts of her daring journeys.
It's certainly possible that Earhart's love for tomato juice and her aviation bona fides got mixed together and embedded in the American psyche, one woman's quirk turned into convention. As the airline business grew, so did its connection to the novel beverage of the era, Earhart's "all-reliable."
The cultural and scientific explanations for the tomato-airplane link aren't mutually exclusive. It could be true that Earhart's preference for tomato juice arose from some of the same facts of physiology that are talked about today: low pressure, loud noise, a loss of sweet and salty taste, a gain in umami sensitivity.
In any case, tomato juice and planes have been together from the start. In October 1965, around the time when researchers first began to look into the sense of taste at altitude, Ohio made a formal declaration: Tomato juice would be the state's official beverage — a fitting choice for the birthplace of aviation. Half a century on, tomato juice remains the standard beverage of the skies.
Daniel Engber is a science writer and contributing editor at Slate.
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