Ancient yeast has been coaxed back to life, and the result is a pint-sized portal to the past. Israeli archeologists and brewers have made beer from millennia-old yeast strains in ancient pottery across Israel, offering a tantalizing taste of the ancient world.
Reviving the flavors of the past
The yeast samples were found in nearly two dozen ceramic jars at archeological sites in Egypt, Philistine, and Judea, dating from 3,000 B.C. to the 4th century B.C. The sites included a 5,000-year-old Egyptian brewery near the Gaza Strip and a Persian-era palace in Jerusalem.
The earliest evidence we have found of beer-making comes from around 13,000 years ago from a site located near Haifa, Israel. So it’s perhaps no coincidence that the resilient beer yeast was found nearby.
These ancient yeast colonies, preserved for millennia in pottery nano-pores, offered a rare glimpse into the brewing techniques of early civilizations.
“Our research offers new tools to examine ancient methods, and enables us to taste the flavors of the past,” said Ronen Hazan of the Hebrew University School of Dental Medicine. “The greatest wonder here is that the yeast colonies survived within the vessel for thousands of years — just waiting to be excavated and grown,” Hazan continued. “This ancient yeast allowed us to create a beer that lets us know what ancient Philistine and Egyptian beer tasted like.”
Resurrecting ancient yeast
Archeologists and microbiologists from the Israel Antiquities Authority and four Israeli universities partnered to study these yeast colonies in 2019. These resilient organisms, trapped in a state of suspended animation, have defied the passage of centuries. While in this state, metabolic activities are significantly reduced, allowing the yeast to survive extended periods without nutrients. And some yeast species can also form spores, which are even more resistant to environmental stressors. These will later grow into yeast once the time is ripe.
The researchers succeeded in “resurrecting” the ancient yeast using advanced DNA sequencing and imaging techniques. The scientists worked with a professional craft brewer in Jerusalem, who helped them brew a basic ale, the kind people in the Levant likely enjoyed in biblical times. However, this is not a perfect recreation of ancient ale since they added hops — a modern ingredient not available in ancient times.
The researchers in Israel stress that the hops aren’t all that important as much of the flavor is from the yeast. The different yeasts emitted distinct gases during fermentation, influencing the flavors and aromas based on their genetic makeup.
Shmuel Naky, a brewer at the Jerusalem Beer Center, described the beer as “spicy, somewhat fruity, and very complex in flavor.”
A taste of history
This successful brewing of ancient beer is just the beginning. Dr. Hazan mentioned plans to add a sensitive genetic screen to their methods, which could provide more detailed insights into the yeast present in the ancient vessels. Combining residue and plant seed analysis may reveal additional ingredients used in ancient brewing.
The team plans to use these revived yeasts with ancient beer recipes, hoping to further explore and recreate historical brews. According to Hazan, the study is a significant step forward for experimental archaeology and could extend to recreating other fermented foods like cheese, wine, and pickles.
“By the way, the beer isn’t bad. Aside from the gimmick of drinking beer from the time of King Pharaoh, this research is extremely important to the field of experimental archaeology — a field that seeks to reconstruct the past,” Hazan added.
