Using yeast that lay dormant for thousands of years, a team of Israeli biologists, archaeologists and beer makers has successfully brewed the beer that Goliath of Gath may have quaffed as he set out to meet a young shepherd named David. And assuming seed funding is secured, soon the brew will hit supermarket shelves, too.
In a multi-layered, interdisciplinary long-term experiment, scientists isolated six yeast strains from 21 sherds of beer or wine vessels excavated from four ancient Holy Land sites. Once populated by Philistines, Canaanites, Egyptians, or Judeans, the sites include biblical Tell es-Safi/Gath (ca. 850 BCE), Bronze Age En-Besor in the Negev and an Egyptian brewery found in Tel Aviv’s Ha-Masger Street (both ca. 3100 BCE), and Jerusalem’s Ramat Rachel (ca. 8th to 4th century BCE).
After DNA sequencing and other high-tech medical imaging and identification methods, the six isolated strains of viable yeast were successfully revitalized and used to brew potable “ancient beers.” Each brew had a different aroma depending upon the yeast strain, according to the recent peer-reviewed mBio journal paper “Isolation and Characterization of Live Yeast Cells from Ancient Vessels as a Tool in Bio-Archaeology.”
The experiment was initiated by Dr. Ronen Hazan, a microbiologist at the Hebrew University’s Institute of Dental Sciences and School of Dental Medicine and his biologist colleague Michael Klutstein, alongside brewmaster Itai Gutman, who at the time owned a brewery in Jerusalem. Eventually, the scope of the project grew to include archaeologists and other scholars from the Hebrew University, the Israel Antiquities Authority, Tel Aviv University and Bar-Ilan University.
“We are talking about a real breakthrough here. This is the first time we have managed to produce ancient alcohol from ancient yeast. In other words, from the original substances from which alcohol was produced. This has never been done before,” said archaeologist Dr. Yitzhak Paz from the Israel Antiquities Authority in a press release.
Further elaborating to The Times of Israel, Paz said, “This is the first time that living yeast were actually extracted, identified and recreated from ancient pottery vessels, and furthermore, they were used in producing alcoholic beverages that were consumed in ancient times. This groundbreaking research opens ways to other endeavors that will identify ancient remains of foodstuffs in ancient vessels and will recreate them.”
Initiator Hazan’s core work at Hadassah is much more sober than this current experiment may imply: He is microbiologist who mainly works with bacteriophages (viruses of bacteria). Recently, he noted, for the first time in Israel these bacteriophages were used to cure a patient who suffered from an antibiotic-resistant bacteria, preventing leg amputation.
Hazan told The Times of Israel ahead of the paper’s media launch that the project is the fulfillment of a longtime dream to collaborate with archaeologists. “It was fun for us to work for a change in such a multidisciplinary environment of biologists, archaeologists and crazy beer makers — not to mention also all the beer and fun alongside the research,” he added.
Part of the fun, he said, was working and brainstorming with his students, including Tzemach Aouizerat, who isolated the ancient yeast strains from the clay pottery vessels’ tiny nano-pores. After the strains were purified and DNA sequenced, Dr. Amir Szitenberg from the Dead Sea and Arava Science Center aided in its analysis and found that some of the ancient strains were similar to modern yeast, or those used today in traditional African beers.
In a melding of science and craft brewing, the isolated yeasts were separately brewed with the help of the beer expert Guttman, using the same standard modern recipe. The resulting brews had vastly differing tastes: During fermentation, the different yeasts emit different gases with flavors or aromas based upon their genetic makeup and original source.
In the next step of the experiment, the scientists isolated these ingredients from the gas produced in the yeasts’ fermentation to understand what was potentially in the original brew the organisms were used in thousands of years ago.
According to the IAA press release, the beers’ flavors and fragrances were chemically analyzed by Dr. Eliyashiv Drori from Ariel University, as well as a team of certified tasters on behalf of the International Beer Judge Certification Program (BJCP) led by Shmuel Nakai.
Anatomy of an ancient brew
The two pottery beer jugs unearthed from the excavation at Tell es-Safi/Gath do not look like German beer steins. They are rounded, vase-like vessels, with a spout emanating from the clay body. Behind the spout are holes like one would see on the end of a modern watering can, which would have partially filtered the brew. The majority of the beer produced in the study was produced from yeast found on these jugs.
Beer was a basic commodity in the ancient world and was consumed by rich, poor, adults and children, according to Paz, as well as used in religious ritual. As indicated by the ancient strainer-stein, ancient beer was not the clear amber substance we recognize today and it would have been filled with sediment, and produced from a variety of grains, including millet, corn, sorghum, and wheat. Other ancient beverages also made with yeast that are historically thought to have been served in such jugs include mead (a beverage made of water and honey) and wine.
The single-cell organism yeast comes in over 1,500 strains and occurs naturally in a variety of habitats, including in salty seas, in soil, and between sweaty toes. Many wines utilize the yeast found on grape skins, but others intentionally add different strains to produce different flavors or effects.
Until relatively recently in human history, when commercial production began around the turn of the 20th century, the strains were isolated by trial and error. Those yeast strains that were found suitable for brewing or baking were often carefully guarded in “starters,” usually a soupy mix of active yeasts. Today, sourdough bread is still baked using this principle.
According to the experiment’s paper, the scientists took 12 samples from two well-preserved Philistine jugs. Each of these vessels yielded a yeast strain, designated TZPlpvs7 — which turned out to be a member of the family isolated from traditional African beers brewed with sorghum malt — and TZPlpvs2 — which turned out to be Saccharomyces cerevisiae, the most commonly used species of domesticated yeast for modern beer, wine, and bread industries.
“The findings are painting a portrait that supports the biblical image of drunken Philistines,” joked Tell es-Safi/Gath excavation head Prof. Aren Maier.
Is it really what Goliath of Gath quaffed?
Just how authentic is the taste of these reconstructed ancient brews?
“This is very tricky,” admitted Hazan. “Beside the fact that we used modern ingredients, keep in mind that we managed to isolate only few yeast out of probably many more which were in the original beer sourdough. Thus, we do not know what was exactly the taste.”
Archaeologist Paz said all the strains were “drinkable.” As far as how close they were to the authentic ancient brews, he said, “The point is that the most important ingredient, yeast, is ancient, and since the product was very close to beers that are known today in Ethiopia and elsewhere, we believe that the flavor we achieved is very close if not identical to the one that was known in ancient times.”
The published paper only presents the first stage of the long-term experiment, Hazan said.
“We intend to add a sensitive genetic screen to our isolation method. This might add more knowledge about the yeast that were present in the clay. In addition, combined residue analysis and plant seeds analysis into the method will show also which ingredients and plants were used in brewing. All together these will hopefully allow us to achieve an even closer look at the authentic taste,” said Hazan.
In the future, said Hazan, the team plans to use an ancient recipe to more accurately reconstruct the ancient beverages.
The yeast research has opened the door to the recreation of more foodstuffs from the past, according to Hazan.
“This study is important in several aspects. First, it opens new avenues to the field of experimental archaeology which try to reconstruct things from the past. Second, it has implication on the study of human dietary and microorganisms domestication. Our methods are not limited to yeast but also can shed light on cheese, wine, pickles and any other fermented food,” he said.
So when can we taste this ancient brew?
“Currently we are working with Yissum, the R&D company of the Hebrew University, to find investors who are interested in commercializing it,” said Hazan.