McDonnell started his research by reading the Ebers Papyrus, an Egyptian text from around 1550 B.C.E. that contains hundreds of medicinal recipes promising cures and treatments for everything from male baldness to crocodile bites. He narrowed his focus to the approximately 75 recipes that referenced beer and listed all the ingredients on a spreadsheet.

From there, he sorted the list by the most common ingredients, which turned out to be eight items: Egyptian balsam fruit (desert dates), Yemeni Sidr honey, sycamore figs, black cumin, juniper berries, Israeli golden raisins, carob fruit and frankincense, reports the Salt Lake Tribune’s Kolbie Peterson. Meet the Utah man brewing a ‘3,000-year-old’ beer, with yeast from ancient pottery Watch on YouTube Logo

He sourced the rare sycamore figs from a 1,400-year-old grove with help from a friend conducting research in Egypt. And for the base grains, he landed on purple Egyptian barley and emmer wheat, an ancient grain known as farro in Europe.

For the yeast, he got in touch with a German company called Primer’s Yeast that brings together archaeologists, microbiologists and other experts to resurrect ancient yeast strains. From the company, he was able to snag a strain of yeast that had been taken from a piece of pottery in Israel. The strain dates to around 850 B.C.E. and was likely used by the Philistines for making beer.