CLEVELAND -- The beer was full of bacteria, warm and slightly sour.
By contemporary standards, it would have been a spoiled batch here at Great Lakes Brewing Company, a craft beer maker based in Ohio, where machinery churns out bottle after bottle of dark porters and pale ales.
But lately, Great Lakes has been trying to imitate a bygone era. Enlisting the help of archaeologists at the University of Chicago, the company has been trying for more than year to replicate a 5,000-year-old Sumerian beer using only clay vessels and a wooden spoon.
"How can you be in this business and not want to know from where your forefathers came with their formulas and their technology?" said Pat Conway, a co-owner of the company.
As interest in artisan beer has expanded across the country, so have collaborations between scholars of ancient drink and independent brewers willing to help them resurrect lost recipes for some of the oldest ales ever made.
"It involves a huge amount of detective work and inference and pulling in information from other sources to try and figure it out," said Gil Stein, the director of the Oriental Institute of the University of Chicago, which is ensuring the historical accuracy of the project. "We recognize that to get at really understanding these different aspects of the past, you have to work with people who know things that we don't."
There is an unresolved argument in academic circles about whether the invention of beer was the primary reason that people in Mesopotamia, considered the birthplace of Western civilization about 10,000 years ago, first became agriculturalists.
By about 3200 B.C., around the time the Sumerians invented the written word, beer had already held a significant role in the region's customs and myths. Sipped through a straw by all classes of society, it is also believed to have been a source of drinkable water and essential nutrients, brewed in both palaces and in average homes. During the rule of King Hammurabi, tavern owners were threatened with drowning if they dared to overcharge.
But for all the notes that Sumerians took about the ingredients and the distribution of their libations, no precise recipes have ever been found. Left behind were only cuneiform texts that vaguely hint at the brewing process, perhaps none more poetically than the Hymn to Ninkasi, the Sumerian goddess of beer.
The song, dated around 1800 B.C., had entranced modern brewers before. A brew based on the hymn was made as part of a partnership in the early 1990s between Anchor Brewing Company in San Francisco and the University of Chicago, where a well-known interpretation of the text was translated in 1964.
Reproductions of ancient alcohols have since grown in popularity, largely through a partnership between the Dogfish Head Craft Brewery in Delaware and Patrick E. McGovern, an archaeological chemist at the University of Pennsylvania Museum. Together, they have recreated beers from prehistoric China, from ancient Egypt and from evidence found in what is believed to be the tomb of King Midas.
"Of different people who do fermented beverages, microbrewers are the most willing to experiment," Dr. McGovern said. "They're ready to try anything."
Great Lakes has no plan to sell its brew, also based on the Hymn to Ninkasi, to the public. The project, unlike others that recreate old recipes on modern equipment, is an educational exercise more than anything else. It has been shaped by a volley of e-mails with Sumerian experts in Chicago as both sides try to better understand an "off the grid" approach that has proved more difficult than first thought.
In place of stainless steel tanks, the Oriental Institute gave the brewery ceramic vessels modeled after artifacts excavated in Iraq during the 1930s. In keeping with the archaeological evidence, the team successfully malted its own barley on the roof of the brew house. It also asked a Cleveland baker to help make a bricklike "beer bread" for use as a source of active yeast -- by far the most difficult step in the process.
The archaeologists, who have committed their careers to studying Sumerian culture, said having professional brewers involved in the effort had helped them ask questions they had not considered.
"We keep going back to the evidence and finding new hints that can help us choose between different interpretations," said Tate Paulette, a doctoral student and a lead researcher on the project. "We are immersed in studying Mesopotamia, and this is a fundamental thing that we don't understand well enough."
While the project continues, Great Lakes' brewing vessels are already a popular addition to guided tours of the brewery. The company is making plans to showcase its Sumerian beer at events in Cleveland and Chicago by the end of this summer, offering a public tasting of the final brew alongside an identical recipe made with more current brewing techniques.
In the meantime, there is still some tweaking to do.
After months of experiments in the brewery's laboratory, Nate Gibbon, a brewer at Great Lakes, said he had stood over a ceramic vat on a recent Wednesday, cooking outside on a patch of grass. The fire that heated the vat was fueled by manure.
The batch, spiced with cardamom and coriander, fermented for two days, but it was ultimately too sour for the modern tongue, Mr. Gibbon said. Next time, he will sweeten it with honey or dates.
Without sophisticated cleaning systems to rid the vessels of natural bacteria, Mesopotamian imbibers might have been more familiar with the brew's unwanted vinegar flavor, archaeologists said. Yet even with the most educated guesswork, they said, the Sumerian palate might never be fully uncovered."We're working with questions that are not going to have a final answer," Mr. Paulette said. "It's just back and forth, trying to move toward a better understanding. We're pretty comfortable with that."
This article originally appeared in The New York Times.