Movie theater popcorn is a concession stand staple whose scent has spawned marketing ploys and copycat recipes, but movie theaters haven't always been saturated with the tempting smell of salt and butter. The history of popcorn is vast, and it intersects with movies in the relatively recent past–a symbiosis of taste and place created to save the fledgling movie theater industry from near collapse during the Great Depression.

About 8,000 years ago, maize was cultivated from teosinte, a wild grass that doesn't look much like the modern corn we know today. Popcorn–a name mostly associated with puffed kernels of corn–is actually a strain of corn, characterized by especially starchy kernels with hard kernel walls, which help internal pressure build when placed over heat. It was one of the first variations of maize cultivated in Central America. "Popcorn went north and it went south, but as far as I can see, it really only survived in South America," says Andrew Smith, author of Popped Culture: A Social History of Popcorn. Eventually, trade and commerce brought the unique kernels northward. "Most likely, North American whalers went to Chile, found varieties of popcorn, picked them up and thought that they were cute, and brought them back to New England in the early 19th century," Smith explains.

After popcorn made its way to the eastern part of North America, it spread rapidly. Eaters found the act of popping corn wildly entertaining, and by 1848, popcorn, the snack food, was prevalent enough to be included in the Dictionary of Americanisms. Popcorn had literally exploded onto the scene and was available everywhere—especially at entertainment sites like circuses and fairs. In fact, there was really only one entertainment site where the snack was absent: the theaters.

One reason for popcorn's increasing popularity was its mobility: in 1885, the first steam-powered popcorn maker hit the streets, invented by Charles Cretor. The mobile nature of the machine made it the perfect production machine for serving patrons attending outdoor sporting events, or circuses and fairs. Not only was popcorn mobile, but it could be mass-produced without a kitchen, an advantage that another crunchy snack—the potato chip—lacked (the earliest potato chips were made in small batches in kitchens, not ideal for mass snack appeal). Another reason for its dominance over other snacks was its appealing aroma when popped, something that street vendors used to their advantage when selling popcorn. Still, movie theaters wouldn’t allow the popular street snack into their auditoriums.

"Movie theaters wanted nothing to do with popcorn," Smith says, "because they were trying to duplicate what was done in real theaters. They had beautiful carpets and rugs and didn't want popcorn being ground into it." Movie theaters were trying to appeal to a highbrow clientele, and didn't want to deal with the distracting trash of concessions—or the distracting noise that snacking during a film would create.

When films added sound in 1927, the movie theater industry opened itself up to a much wider clientele, since literacy was no longer required to attend films (the titles used early silent films restricted their audience). By 1930, attendance to movie theaters had reached 90 million per week. Such a huge patronage created larger possibilities for profits—especially since the sound pictures now muffled snacks—but movie theater owners were still hesitant to bring snacks inside of their theaters.

The Great Depression presented an excellent opportunity for both movies and popcorn. Looking for a cheap diversion, audiences flocked to the movies. And at 5 to 10 cents a bag, popcorn was a luxury that most people were able to afford. Popcorn kernels themselves were a cheap investment for purveyors, and a $10 bag could last for years. If those inside the theaters couldn't see the financial lure of popcorn, enterprising street vendors didn't miss a beat: they bought their own popping machines and sold popcorn outside the theaters to moviegoers before they entered the theater. As Smith explains, early movie theaters literally had signs hung outside their coatrooms, requesting that patrons check their popcorn with their coats. Popcorn, it seems, was the original clandestine movie snack.

Beyond wanting to maintain appearances, early movie theaters weren't built to accommodate the first popcorn machines; the theaters lacked proper ventilation. But as more and more customers came to the theater with popcorn in hand, owners couldn't ignore the financial appeal of selling the snack. So they leased "lobby privileges" to vendors, allowing them to sell their popcorn in the lobby of their theater (or more likely on a bit of street in front of the theater) for a daily fee. Vendors didn't complain about this arrangement—selling popcorn outside the theater widened their business potential, as they could sell to both moviegoers and people on the street.

Eventually, movie theater owners realized that if they cut out the middleman, their profits would skyrocket. For many theaters, the transition to selling snacks helped save them from the crippling Depression. In the mid-1930s, the movie theater business started to go under. "But those that began serving popcorn and other snacks," Smith explains, "survived." Take, for example, a Dallas movie theater chain that installed popcorn machines in 80 theaters, but refused to install machines in their five best theaters, which they considered too high class to sell popcorn. In two years, the theaters with popcorn saw their profits soar; the five theaters without popcorn watched their profits go into the red. Eventually, movie theater owners came to understand that concessions were their ticket to higher profits, and installed concession stands in their theaters.

World War II further solidified the marriage between popcorn and the movie theaters. Competing snacks like candy and soda suffered from sugar shortages and in turn, rationing, as traditional sugar exporters like the Philippines were cut off from the United States.

By 1945, popcorn and the movies were inextricably bound: over half of the popcorn consumed in America was eaten at the movie theaters. Theaters began pushing advertisements for their concessions harder, debuting commercials that played before (and sometimes in the middle of) movies that enticed audiences to check out the snacks in the lobby. Maybe the most famous of these is "Let’s All Go to the Lobby," a 40-second advertisement that debuted in 1957.

In 2000, the advertisement was selected by the Library of Congress for preservation in the United States National Film Registry due to its cultural and historical value.

But for all their marketing ploys, movie theaters saw their popcorn sales steadily decrease into the 1960s. The culprit was a new technology, the television, which lessened the need to go out to the movies. "The popcorn industry sags in the '50s as Americans begin to watch more and more television and go less and less to movie theaters," Smith says.

Popcorn wasn't widely eaten in homes, mostly due to how difficult it was to make: consumers needed a popper, oil, butter, salt and other ingredients to replicate their favorite movie theater snack at home. To ease this burden, one commercial product, EZ Pop, marketed itself as an all inclusive popcorn maker–simply move the container over a heat source, and the popcorn pops, completely flavored. After EZ Pop came Jiffy Pop, a famous at-home popcorn product that used the same "all-in-one" philosophy. By making popcorn an easy-to-make snack, commercial popcorn products were able to gain a foothold in the home. In the 1970s, microwave ovens become increasingly common in homes, creating another boom for popcorn: now, families can enjoy popcorn in minutes simply by pressing a button.

As popcorn re-entered the home, traditional associations of popcorn and movies, or popcorn and entertainment, persisted. Nordmende, a German electronics company, even used popcorn to advertise its microwave, purporting it to be a "sponsor of the midweek movie."

Nowadays, the popcorn industry attaches itself to our home movie nights in a very direct way, through commercials that directly engage with popular films or "movie theater" styles of microwave popcorn that market themselves as a direct replica of the beloved theater snack.

But the relationship between popcorn and the movies has changed more than the smell of a theater lobby or the at-home movie night: it's changed the popcorn industry itself. Before the Great Depression, most popcorn sold was a white corn variety–yellow corn wasn't widely commercially grown, and cost twice as much as the white variety. Movie vendors, however, preferred yellow corn, which expanded more when it popped (creating more volume for less product) and had a yellowish tint that gave the impression of a coating of butter. People became accustomed to the yellow popcorn and would refuse to buy the white variety at markets, requesting the kind that looked like "the popcorn at the movies." Today, white popcorn accounts for 10 percent of commercially grown popcorn; yellow popcorn takes up almost the rest of the commercial market (with some color varieties, like blue and black, grown in negligible amounts).

Popcorn is just as economically important to the modern movie theater as it was to movie theaters of old. Patrons often complain about the high prices of movie concessions, but there's an economic basis for this: popcorn, cheap to make and easy to mark-up, is the primary profit maker for movie theaters. Movie theaters make an estimated 85 percent profit off of concession sales, and those sales constitute 46 percent of movie theater's overall profits.

And so the history of popcorn and the movies was written in stone—sort of. In recent years, luxury theaters have begun popping up around the country–and they're reinventing the popcorn-snack model. These theaters offer an old school approach to the movies, trying to make the experience of attending a movie theater tantamount to going to a live show (much like the earliest movie theater owners once tried to do). As Hamid Hashemi, the CEO of iPic Theaters, a luxury theater chain with nine locations, says, "Think about going to a live Broadway show—our movie theaters provide that kind of experience. The average time spent in the theater at our theaters is around four hours." iPic Theaters still provide popcorn to patrons, but their focus is on a more gourmet level of movie theater dining, offering a menu of larger, cooked items like sliders and flatbreads.

Even as the demand for luxury theaters increases, Hashemi doesn’t think popcorn will ever be phased out. "Popcorn is the cheapest thing you can make, and to a lot of people it has that ritualistic experience," he says, suggesting that for movie theater owners, a cheap snack never loses its golden appeal.

