Brewing history: Yale course recreates ancient ales, mixing science, anthropology, history

Text by Mike Cummings, YaleNews

For several hours on a recent Friday morning, a Yale laboratory became a Bronze Age brewery.

Inside the lab, in the Yale Chemistry Research Building, a group of students attempted to recreate beers of the kind imbibed in Egypt and Assyria thousands of years ago. As brewery aromas of bread and caramel wafted through the space, students took turns stirring two large, canvas-lined metal pots of ground barley in heated water under the guidance of their faculty instructors.

The five students — divided into groups of two and three — stirred the barley mash for an hour at 68 degrees Celsius, drawing the sugars from it, a crucial step in brewing beer. In the process they faced a small, technological challenge their ancient counterparts never encountered: The lab’s electric burners required frequent adjustment to maintain a constant water temperature. 

“It’s been a little tricky,” said Rowan Thakur, a computer science major as he checked the temperature with a digital thermometer. “You need to keep an eye on it.”

The student researchers are enrolled in “Unequal: Dynamics of Power and Social Hierarchy in Ancient Egypt and Mesopotamia,” an interdisciplinary course that examines the historical roots of intolerance, slavery, and imperialism, emphasizing how perceptions of history shape contemporary beliefs and policies. 

“Beer, feasting, and food are central to questions about social hierarchies,” said Vincent Morel, a postdoctoral associate and lecturer in the Department of Near Eastern Languages and Civilizations, in Yale’s Faculty of Arts and Sciences, who co-teaches the course with Gojko Barjamovic, a senior lecturer and senior research scholar in Assyriology. “Eating and drinking together plays an important role in how people define themselves vis-à-vis their neighbors.”

Supporting the students’ efforts was an interdisciplinary team of Yale scholars, including archaeological scientists and biochemists, who guided the work — and even isolated yeast strains that ancient brewers might have used.

“Together with the talents of our Yale undergraduates, we’re collaborating across often-rigid disciplines to recreate, down to its DNA, a creative and scientific enterprise humans developed thousands of years ago,” Barjamovic said. “As they experiment with brewing, the students are creating data that could provide important insights into an organic product that was widely consumed by societies throughout antiquity.”

The students need to be 21 years old to sample the beer. Sampling in the lab was strictly prohibited. Brewing is just one of several innovative assignments and activities Barjamovic and Morel have incorporated into their course to help students engage creatively with the past. 

In a research project associated with the brewing experiment, a group of students is working with the Yale Ancient Pharmacology Program (YAPP) to gather and analyze data on the trace residues left on replicas of ceramic vessels likely used in ancient beer production.

Two other course assignments focus on the dissemination of knowledge. One group of students is organizing an exhibit at the Yale Peabody Museum. Another serves a journalist-like role, documenting the course and its various projects. 

“The teaching strategy can loosely be described as ‘experimental history,’” Barjamovic said. “We train students in articulating research questions and designing projects that can answer historical problems through the applied sciences. Our ambition is to explore how two profoundly different disciplines within the liberal arts curriculum can be combined to enhance and deepen student learning in both.” 

Combining historical sources with scientific lab work helps students appreciate processes of social change and technological innovation through emulation and discovery, he explained.

Educated guesses

In devising their beer recipes, the students drew from the archaeological record. 

They were provided copies of the Hymn to Ninkasi, a work of Mesopotamian literature dedicated to the Sumerian beer goddess, which contains the outline of a brewing process. The hymn, about 4,000 years old, exists in cuneiform tablets housed in Berlin and London and is accessible to anyone with an internet connection.

“We have vague gesticulations in the direction of what ancient brewers did, so we’re making some educated guesses and seeing what happens,” said Thakur, a computer science major.

Those educated guesses were guided by Vanessa Todorow and Zane Johnson, postdoctoral associates in the Department of Molecular Biophysics and Biochemistry, who were recruited for the experiment by Barjamovic when he learned that they were knowledgeable about brewing. 

For the “ancient” beer, Johnson isolated two strains of wild yeast from dates endemic to the Euphrates Valley, believing that it might most closely recreate the variety of yeasts that ancient Mesopotamians used to brew beer.

“Fermentation of ancient beer probably included a lot of microorganisms, both yeast and bacteria,” Johnson said. “For the purposes of food safety, we wanted to know what would be going into this beer if people were going to be trying it. To that end, I sequenced the DNA and figured out exactly which species of yeast I got from the dates.”

Thakur and his brewing partner, Tane Potts, a first-year student, used both yeast strains to ferment their product. 

The other group — composed of senior Sam Gallagher, junior Astou Naouyate, and first-year Metztli Lopez — chose a different method. They made a bappir, a barley bread used in ancient Mesopotamian beer brewing that is comparable to a sourdough starter. 

While stirring the barley mash, both groups added date syrup to flavor the brew. The specific amount they used was up to them. 

“How much is a lot of date syrup?” Lopez said. 

“Just go with your gut feeling,” Todorow replied. “I can’t tell you.”

After an hour, the students separated the mash from the wort, the sugary solution that would undergo fermentation. The students pulled the canvas bags filled with mash from the hot water, squeezing excess liquid into the pots.

Thakur and Potts boiled their wort for an hour, which helps with sterilization and flavor. Both groups added saffron for color and flavor. Once the wort cooled down, they added yeast or bappir. Fermentation takes about a week. 

“We’ll see what happens,” Gallagher said.

For Lopez, the experiment is what led her to apply for the class. 

“Personally, I’m very interested in the concept of culinary anthropology and how food and drink can be used as a way to understand ourselves and each other,” she said. 

Gallagher, who is of legal drinking age, says he took the course because his parents are home brewers and he wanted to better understand the brewing process. Even if his group’s beer turns out well, he likely won’t enjoy drinking it.

“Ironically, I hate beer,” he said. “But I’m discovering that the process of making it is pretty cool.”

Importance of experimentation

As the students stirred the pots of mash, a batch they had brewed a week earlier fermented inside a large ceramic bowl in a nearby cabinet. The residues left inside that bowl yielded a separate experiment.

Working with Yale chemists and YAPP researchers, another group of students will analyze those residues, a process that could shed light on how ancient people’s produced and consumed beer. 

YAPP is a multidisciplinary initiative based in the Peabody that harnesses ethnography, science, and technology to uncover evidence of how people lived thousands of years ago. Its researchers study the organic residues found on or within ancient vessels, providing insight into ancient people’s diets and lifestyles. 

“The students’ experiment will provide us extremely useful baseline data that we wouldn’t otherwise have,” said Andrew Koh, the YAPP director and a museum scientist at the Peabody. “It will be immensely helpful when we’re examining vessels and pottery sherds that we suspect may have been used in the production or consumption of beer.” 

For the residue experiment, the students were equipped with three replicas of ceramic vessels that scholars think might have been used to brew beer in Mesopotamia. 

“These vessels are typical for central Iraq around 2400 BCE.,” Barjamovic said. “They were first discovered in tombs, but now they’re ubiquitous. Scholars have suggested two possibilities for their use. One is for an elaborate handwashing ritual. The other is beer brewing.”

The vessels consist of three components: a large bowl, a tower that sits in the bowl’s center and is pierced with holes along its sides, and a small bowl-shaped piece with a hole in its bottom that sits atop the tower. 

Maishe Dickman, a potter and museum technician at the Peabody, made three sets of the vessels based on specifications Morel and Barjamovic provided him. He also produced dozens of ceramic tiles baked in the same firing event as the vessels.

The student used the vessels to make beer using varied recipes drawn from the Hymn to Ninkasi. They placed the mash into the top bowl and poured hot water onto it. The water filled the tower and trickled into the large bowl through the tower’s holes. The tiles were soaked in the brew as it fermented. 

The tiles and vessels will be analyzed to identify what substances remain in the pottery over time. 

“Since the pottery is a porous material, we will have a material transfer of the liquid into it and that might or might not preserve specific types of molecules of different qualities,” said Fabian Menges, an analytical chemist in the Department of Chemistry who is assisting with the research project. 

The students will use alcohol to extract soluble sugars form the pottery and hexane to recover fatty acids and other insoluble substances.

Some of the tiles or sherds of the vessels will be buried and analyzed at different intervals of time — weeks, months, years, etc. — to provide YAPP researchers useful baseline data concerning which molecules are preserved in the pottery over time, and which are ingested by microorganisms, Menges explained. 

It is the sort of multidisciplinary research effort that can only happen at places like Yale, Koh said. 

“On top of that, the students are learning the importance of experimentation in developing knowledge and expertise,” he said. 

As for the student-brewed beer, well, it serves as a reminder that failure is a crucial component of the scientific endeavor.

“Brewing in the ceramic vessels was a learning experience for sure,” Barjamovic, the course’s co-teacher, said. “One beer tasted good to me, the other, to be honest, was pretty awful. 

“The thing is, of course, that in these matters, one learns equally well from success and failure.”