By Published: Sept. 25, 2024

In CUriosity, experts across the CU Boulder campus answer pressing questions about humans, our planet and the universe beyond.

Oktoberfest, the German beer festival, kicked off this week in Munich. To mark the occasion, Travis Rupp, assistant teaching professor in the Department of Classics, tackles the question: “How old is beer?”

Man in flannel shirt wearing safety glasses sits next to equipment with lots of tubesTravis Rupp recreates historic beer recipes from his research brewery in his garage. (Credit:Sara Herkes Photography and Design)

Humans are no strangers to kicking back with a cool pint of beer. The Ancient Egyptians, for example, had a hankering for beer that was a little bit tart, almost like a modern-day gose, a lemony beer from Germany. Homer, the Ancient Greek poet, spoke of a beverage called κυκέων (pronounced “kee-kay-own), which was a mixture of grape wine and fermented grains.

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But exactly how old is beer? Old, says Rupp. Really, really old.

Rupp, a.k.a. the “,” has arguably one of the tastiest jobs in academia. He travels the world to learn how ancient cultures made beer, then recreates those recipes in a research brewery in his garage. Currently, he’s aging two variations of Homer’s Greek libation, which, Rupp said, are higher in alcohol than traditional beers.

“When I’m drinking a glass of wine, typically I want to sip on it with my wife,” he said while sipping on a Kiwi Herman New Zealand Lager at in Boulder, babyֱapp. “If I’ve got scotch out, I want alone time…But when it’s beer, I want to drink beer with other people. Beer has been the thing that’s bound us together for a long time.”

To date, the oldest known evidence of beer brewing comes from a . Residents of Raqefet Cave used open mortars in the bedrock to crush and soak plant starches, transforming them into sugars—what brewers today call the mashing process. They then fermented those sugars in containers made from fibers.

The kicker: The Raqefet Cave site dates back to around 11,000 BCE, which makes beer, as far as we now know, about as old as agriculture itself.

“As science progresses, I think both of those dates are going to continue to get pushed back,” Rupp said.

Man in a t-shirt and shorts photographs natural holes in the floor of a cave

Ancient peoples crushed and soaked plant starches in these mortars in Raqefet Cave in Israel as part of the brewing process. (Credit: byDani Nadel via )

Defining beer

Such ancient sites also challenge what hop-heads might consider beer. Today’s brews, Rupp noted, are mostly made from cereal crops like barley, wheat or rice. But residents of Raqefet Cave made their beverages from a mix of wild-harvested grains and other plants like tubers and fruit.

More modern-tasting beer, the kind American consumers would be familiar with, at least, emerged, in part, in Bavaria in the 15th Century.

At the time, brewers, who were trying to escape taxes on a range of herbs, began to flavor their beers more often with hops, which weren’t taxed. In response, William IV of Bavaria enacted the Bavarian Purity Law in 1516, strictly defining beer as a beverage made from only three ingredients: water, barley and hops. The regulations stuck around, eventually becoming the Reinheitsgebot, or “purity order,” that continues to shape the German beer industry today.

“Migrants coming into the U.S. in the 19th century like Adolph Coors, the Anheuser family and the Miller family all had a German brewing background,” Rupp said. “That’s why, up until the craft beer movement of the 1990s, American beer was lager.”

Rupp believes we should not put limits on what counts as beer—he defines it only as a drink that is brewed then fermented. That way, brewers can continue to experiment with wild flavors like peach sours, chocolate mole stouts and even, yes, ancient wine-beer hybrids.

Consider it the continuation of a very, very long tradition.