I need a beer.

It’s a phrase uttered by many contemporary workers after a long day at the office, but new research shows that ancient cultures were probably using the alcoholic beverage to treat much more than the stress of everyday life.

Anthropologists have found that thousands of years before the 1928 discovery of penicillin, people in ancient Nubia were using beer as an antibiotic to treat everything from gum disease to infected wounds.

It has been known for some time that the kingdom of Nubia, located south of Egypt in present-day Sudan, valued its brewers. More recently, however, scientists began to suspect that Nubian beer may have been brewed to contain more than just alcohol.

The suspicion arose after archeologists unearthed some unusual physical evidence. In 1980, George Armelagos, an anthropology professor at Emory University in Atlanta, led a team that discovered what seemed to be the antibiotic tetracycline in nearly 2,000-year-old Nubian bones.

Tetracycline is naturally produced by a soil bacteria called streptomyces, and scientists theorized that streptomyces might have thrived in vats of Nubian beer. Recently, a more extended analysis of ancient Nubian bones revealed consistently high concentrations of tetracycline. The new findings suggest the Nubians were regularly consuming tetracycline and had mastered the complicated brewing process necessary to routinely brew antibiotic beer. The conclusion contradicts the notion that antibiotics are a modern invention.

“Discovering the tetracycline was like unwrapping an Egyptian mummy and seeing a pair of Ray-Ban sunglasses strapped to the head,” Armelagos said. “It was that surprising.”

To understand how streptomyces bacteria could enter the beer, it helps to know how ancient brewing practices differed from modern-day techniques. For starters, the Nubians, like the Egyptians, made their beer from bread.

The first step for ancient bakers and brewers was to germinate harvested grain.

“This process is much like how you would do in a fourth-grade germination science project, where the grains would be soaked in water for about 24 hours, drained and then laid between sheets of cloth until they sprouted,” said Amanda Mummert, an anthropology graduate student helping Armelagos with his research.

After germination, the grains were dried and then milled into a flour used to make bread. Streptomyces bacteria most likely entered the beer-making process either during the storage or drying of the grain or when the bread dough was left to rise.

Nubian brewers would take the dough and bake it until it developed a tough crust, but retained an almost raw center. The bread was broken into a vat containing tea made from the unmilled grains. The mixture was then fermented, turning it into beer.

The final product didn’t look much like the pint of amber you sip at your local watering hole.

“When we talk about this ancient Egyptian beer, we’re not talking about Pabst Blue Ribbon,” Armelagos said. “What we’re talking about is a kind of cereal gruel.”

Mummert, who has brewed beer using some of the ancient techniques, described her first batches as malty and sour. Hops, an important ingredient in modern beer, were not available in ancient Africa. The acids in hops work as a preservative, so the Nubians probably drank their beer soon after it was made.

Mummert was drawn to the study of ancient beer technology because it provided an opportunity to examine the evidence of health interventions during early human history.

“Antibiotics are often thought of as a modern laboratory invention, yet this shows that humans have been aware of naturally occurring antibiotic activities for much longer than previously thought,” she said.

Both brewing and medicine have evolved since the days of the Nubians, but scattered historical accounts attest to the fact that people continued to ascribe medicinal properties to beer.

Near the turn of the 17th century, as hops were slowly gaining acceptance in England, some argued that the new ingredient made beer more wholesome. Advertising posters in the 1920s in Ireland proudly proclaimed that “Guinness is Good for You.” And during Prohibition, a group of physicians took their battle for the right to prescribe beer as medicine all the way to the U.S. Supreme Court.

These days beer and medicine cross paths in clinical trials, many of which have found that beer can confer a variety of health benefits.

“Moderate consumption of alcohol, in any form, cuts down the risk of coronary heart disease,” said Charlie Bamforth, a professor of brewing science at UC Davis. In addition to alcohol, he said, beer contains a number of other compounds with known health benefits, including B vitamins and soluble fiber.

Still, the modern beer industry has not been quick to latch onto the idea of medicinal beer.

“When it comes to touting health benefits, brewers are very cautious,” Bamforth said.

Marc Rosenblum, owner of the Santa Cruz Ale Works, certainly is.

“I am afraid that I am probably not the best resource to learn about the health benefits of beer,” he said. “We make it, drink it, like it and just try to sell it.”

Across town at Santa Cruz’s Seabright Brewery, brew master Jason Chavez thinks it unlikely that anyone would drink beer for purely medicinal purposes. He did, however, point out the social aspects of quaffing beer.

Noting that many new ideas and innovations were probably conceived by people sharing a malt beverage, Chavez said, “Without beer we wouldn’t be where we are today.”