In Star Trek, a Starfleet vessel is like a 24-hour IHOP. In space there is no such thing as morning, so breakfast can be eaten anytime, at all times. Likewise, members of Starfleet guzzle caffeine like long-haul truckers: unbound from diurnal rhythm, fighting to stay awake in an unchanging now, an eternal night. Of all sci-fi visions of the future, Star Trek is perhaps the most boring—or, rather, it’s the one most interested in the details. Star Trek is as much office sitcom as space opera. What happens in the mess hall matters.

Caffeine sources in the Star Trek universe are of particular importance. No other beverage or foodstuff gets the kind of prominence that coffee and tea do: ever-present, often discussed, disastrously substituted. Sulu, stuck on an ice planet in The Original Series: “Do you think you might be able to find a long rope somewhere and lower us down a pot of hot coffee?” Picard, in The Next Generation, with his regular order of “tea, Earl Grey, hot.” Kira, presented with a caffeine-free version of raktajino—the Klingon coffee that took over Deep Space Nine’s promenade the same time as Starbucks’s IRL rise: “You make me sound like some kind of addict.” A determined Janeway in Voyager: “There’s coffee in that nebula!” An under-caffeinated Tucker in Enterprise: "I'm no good until I've had my coffee." Desperate to fit in, Deep Space Nine’s Odo, a liquid-based shapeshifter who neither eats nor drinks, transforms part of himself into a coffee cup and consumes it.

Star Trek’s writers play this extreme reliance on caffeine for the kind of gentle jokes on novelty restaurant signs around the world. (“Coffee! You can sleep when you're dead!”) Within the fictional universe, it’s consumption verges on the performative: How much caffeine Starfleet officers drink equals, somehow, how hard they work. Voyager’s chief engineer, B’Elanna Torres, were she not cut off at two pots a day, would down coffee by the gallon. Both viewers and characters are meant to see the habit as benign. 

This open dependence strikes an interesting contrast with Starfleet’s policy toward alcohol. As early as The Original Series, the Federation had outlawed the Gatorade-blue Romulan ale, presumably for being too alcoholic. (The screenplay for the second, and best, Star Trek movie, The Wrath of Khan, says that Romulan ale makes its human drinker “an instant drunk.”) 

Even in Utopia you need a cup of something now and then (and again, and again).

Booze and caffeine are not the same thing—alcohol destroys many things, coffee mostly just stains them. But the Federation’s willingness to make major policy decisions (in this case, a kind of space prohibition) about one and not the other points to caffeine’s not-so-secret role on starships. When faced, for months or years at a time, with windows that all look out on the same expanse, alcohol just sounds like a bad idea. The jittery alternative, whether in the form of earthbound tea or Klingon raktajinos, is the oil with which the ship’s human engine runs, a liquid dilithium distributed through mess halls and replicators.

Viewers are meant to understand the United Federation of Planets as a Utopian ideal of governance, a perfect union of star systems and species. Though human-dominated Starfleet ships can be parochial, hubs like a space station, a conference, or a resort planet are dizzyingly cosmopolitan. Though it’s a military outpost on the edge of Federation territory, Deep Space Nine is also an intergalactic space mall—complete with a Klingon food court, Bajoran storefront place of worship, Cardassian clothing shop, and a Ferengi bar, gambling facilities, and holodecks that can place paying customers inside anywhere from the holonovel Vulcan Love Slave II to a 1950s mob-run casino. 

In this light, it’s no wonder that it’s this crew, of all the series, that has the most adventurous taste in coffee. Deep Space Nine, in more ways than food, splits open many of Star Trek’s central fault lines. That even a relative backwater can boast this variety of services and cultures for consumption is a powerful expression, and representation, of power. It touches on the questions at the heart of Star Trek: Is it possible to have a non-imperial empire? Can power ever be wielded ethically? (If the Federation moves to your neighborhood, is it space gentrification?) 

For answers look to the tea leaves: At least 20 extraterrestrial varieties are mentioned throughout Star Trek, more diverse and far-flung than the British empire could ever imagine. Deka tea, served to Bajoran comfort women during the occupation of their planet. Jestral tea, sought by the Betazoid Lxwana Troi in times of high anxiety. Leola bark tea, a Delta Quadrant remedy for upset stomachs. Red leaf tea, sweet and spicy, favored by Cardassians at breakfast. Tarkalean tea, proscribed to sooth morning sickness. Zariphean tea, which could keep a person awake for three straight days. They are the fruits of “exploration,” of cultural conquest. This multiplicity is thrilling, but it’s complicated, too.

In a fictional universe full of the fantastic—elaborately costumed humanoids and improbable technology existing in, most fabulously, a post-scarcity society, an equitable society, a peaceful society—the fact that everyone is still so thirsty shows Star Trek at its most realistic. Even in Utopia you need a cup of something now and then (and again, and again). Scratch the surface, or take away the coffee, and you can see the desperation on Sulu’s face, on Kira’s face, and most of all on Janeway’s—whose journey home from the far side of the galaxy makes access particularly difficult. There it is, the human limits of space travel. A sleepless person en route to someplace else, pulling over to sit at an empty table—in the mess hall, in their quarters—a cup of coffee in their hand.