A multidisciplinary team of scientists has successfully isolated several yeast strains from ancient vessels excavated at archaeological sites in Israel. The researchers then brewed ‘aromatic and flavorful’ beer using the ancient yeast strains.
“We hypothesized that the enrichment of clay vessels with large amounts of fermenting yeast that were absorbed into the vessel pores of the ceramic matrix permanently changed the vessel’s microorganism content,” said senior author Dr. Ronen Hazan from the Hebrew University of Jerusalem and colleagues.
“Indeed, testing of several modern vessels that were filled with filtered and unfiltered beer and buried for three weeks underground, as well as further tests of a clay wine vessel that had not been used for more than two years, revealed that yeast cells can be found in the clay matrix, after an extended period of time.”
Dr. Hazan and co-authors then looked for ancient yeast cells in beer- and mead-related (honey wine) vessels from several archaeological sites.
“We tested ancient ceramic vessels from three different historical periods, found in four different archaeological sites located in Israel,” they explained.
“Each of these sites contained vessels that were assumed to have been associated with fermented beverages.”
The oldest vessels came from two Early Bronze Age (3100 BCE) sites.
“The first site is En-Besor in the northwestern Negev desert, a site relating to the Egyptian activities in southern Canaan during the late 4th millennium BCE. The second site was recently excavated at Ha-Masger Street in Tel Aviv and contained basin fragments, typical of Egyptian-style breweries, perhaps evidence of an Egyptian enclave within a local Canaanite settlement,” the researchers said.
The third site sampled was Philistine Tell es-Safi/Gath in central Israel.
“The Philistines, one of the so-called Sea Peoples, were an important culture in the Levant during the Iron Age (1200 to 600 BCE) and are often mentioned in the Bible as enemies of the Israelites. At the time, Philistine Gath was the largest and most important Philistine site in the region,” the authors said.
“We tested 12 samples from two well-preserved Philistine jugs of a type usually associated with beer or other fermented alcoholic drinks, based on their spout and a strainer spout on their side.”
“The fourth site was Ramat Rachel, located between Jerusalem and Bethlehem. During the Iron Age and Persian periods (ca. 8th to 4th century BCE), it served as the residence of the local representative of the Assyrian, Babylonian, and Persian empires, as a center for tax collection, and for diacritical feasting events. From this site, we examined four storage jars, typical of the Judean region during the early Persian period.”
The scientists succeeded in isolating six yeast strains from 21 beer- and mead-related ancient vessels.
They then sequenced the full genome of each strain and found that the yeasts are very similar to those used in traditional African brews, such as the Ethiopian honey wine tej, and to modern beer yeast.
Finally, they tested the ability of the isolated yeast strains to produce drinkable alcoholic beverages.
Three of them — from En-Besor, Tell es-Safi/Gath and Ramat Rachel — produced aromatic and flavorful beer.
“The greatest wonder here is that the yeast colonies survived within the vessel for thousands of years — just waiting to be excavated and grown,” Dr. Hazan said.
“This ancient yeast allowed us to create beer that lets us know what ancient Philistine and Egyptian beer tasted like.”
“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.”
“Our research offers new tools to examine ancient methods, and enables us to taste the flavors of the past.”
“We are talking about a real breakthrough here,” said co-author Dr. Yitzchak Paz, from the Israel Antiquities Authority.
“This is the first time we succeeded in producing ancient alcohol from ancient yeast. In other words, from the original substances from which alcohol was produced. This has never been done before.”
The findings appear in the journal mBio.
Tzemach Aouizerat et al. 2019. Isolation and Characterization of Live Yeast Cells from Ancient Vessels as a Tool in Bio-Archaeology. mBio 10: e00388-19; doi: 10.1128/mBio.00388-19