Like many potentially harebrained ideas, Dylan McDonnell’s idea to brew beer from yeast that’s nearly 3,000 years old started during the COVID-19 pandemic. 

In 2020, McDonnell, an avid home brewer, heard about someone who had baked a loaf of sourdough bread with a strain of yeast that’s a descendant of a 4,500-year-old Egyptian yeast. 

McDonnell, who had never brewed professionally and started home brewing with a kit from The Beer Nut, wondered if he could do the same for beer. 

“When I brew beer I’m not necessarily interested in making just an average beer,” he said. “I want to try to push the boundaries of brewing, and I felt using a very old yeast would be a great way to do that for this batch.” 

When McDonnell heard about the sourdough experiments—done in 2019 by Seamus Blackley, a physicist, amateur baker, “gastroegyptologist” and inventor of the original Xbox—he started doing his own research, unaware of any yeast that was commercially available that he could use for such a project. 

In his research, though, he came across Primer’s Yeast, a German company that wanted a home brewer to test out yeast that microbiologists had isolated from ancient pottery in Israel. Primer’s had previously done experiments using “heritage” yeast (or, yeast that is descended from ancient yeast) and modern ingredients to create ancient beer. 

In a video about that project, lab manager Dr. Shunit Coppenhagen-Glazer said microbiologists would take ancient vessels supplied by archaeologists and reanimate yeast molecules that had survived in the ceramic material for millennia, then isolate and characterize the yeast. 

The strain McDonnell ordered in September is called PTS-900BCE, which, according to Primer’s Yeast’s website, is a brewing strain that dates back to 850 B.C.E. and was extracted from the ancient site of Gath of the Philistines in Israel. Today, the site is not much more than hills covered with white rocks and olive trees. 

Expecting his yeast to arrive by December, McDonnell got to work developing a beer recipe and collecting ingredients. But his order became backlogged due to the Israel-Hamas war and did not arrive in December. 

Primer’s Yeast reached out to him in January, though, with the offer of a premarket release of the yeast. Now, he could get back to his recipe. And what else could he do to develop an ancient beer recipe besides consult an ancient text. The Ebers Papyrus is from about 1,550 B.C.E., older than McDonnell’s yeast by approximately 700 years. 

The Ebers Papyrus outlined numerous recipes for folk medicines for various ailments. McDonnell went through about 800 of them, taking the ones that referenced beer, and specifically, the act of drinking beer, and narrowed it down to 75 recipes. 

In those 75 recipes, there were about 120 unique ingredients, and he created his recipe using the ingredients mentioned the most: Egyptian balsam fruit (aka desert dates), figs, golden Israeli raisins, juniper berries, carob fruit, frankincense, Yemeni Sidr honey and black cumin. For the base, he used Emmer wheat and purple Egyptian barley, which is grown in Utah. 

“I took the beer recipes from the Ebers Papyrus and used the most common ingredients that could be verified as the same ingredients today that were used back then,” McDonnell said. “I did this by verifying the ingredients names on the papyrus with the items found in King Tut’s tomb. For example, the recipe calls for figs. There are currently thousands of varieties of figs, but in King Tut’s tomb, the Sycamore fig was specifically present, which is why, to me, it was important to get as authentic ingredients as possible.”

Something that came in handy about the Ebers Papyrus—which had been digitized and translated in English—is that it not only listed the ingredients for beer, it also listed the proportions needed in a recipe. 

After years of planning, research, finding ingredients and brewing, McDonnell finally succeeded in brewing a beer with 3,000-year-old yeast. McDonnell says it’s a relief to have been able to successfully brew it. 

“I wanted to do this the right way, so there was a lot of fact checking and double checking,” he said. “I also bought a lot more ingredients that I anticipated using that I ended up not using because of the various iterations of the recipe I kept toying with to try to get the right one.”

McDonnell compared the process to making ancient ice cream, saying, “There are a lot of different flavors and a lot of different additions can go in to it, and rocky road is vastly different than vanilla, but at the end of the day, when you taste ice cream, you know it’s ice cream.” 

He said that was his goal, to have someone take a sip of the beer and be able to tell what it is. Unfortunately, he said there isn’t really anyone who can do that and say it tastes exactly the same as it did 3,000 years ago. But, he just wanted to “do right by the people who brewed this recipe 3,000 years ago.” 

In all, he ended up with 10 gallons, which is a large yield for a home-brewing project. He estimates it cost him about $1,000 to brew the batch. He ended up with a beer he described as a citrusy sour beer, “but rather than having a bitter hops aftertaste it has more of a floral aftertaste.” 

This 10-gallon batch won’t be available commercially, but an adaptation of McDonnell’s recipe will be available at Primers-Yeast.com. 

To inquire about a private tasting, you can contact Dylan McDonnell at [email protected]. λ