Scientists studying the 5,300-year-old remains of Ötzi the Iceman have successfully baked sourdough bread using yeast discovered on and inside the famous mummy, opening the door to potential new applications in food science and ancient microbiology.
Ötzi, whose naturally preserved remains were discovered by hikers in the Tyrolean Alps near the Italy-Austria border in 1991, has been the subject of extensive scientific research for decades. Previous studies revealed details about his health, diet, and lifestyle, including evidence that he was going bald, had dozens of tattoos, and carried a cancer-causing strain of human papillomavirus.
Now, researchers from the Institute for Mummy Studies at Eurac Research have turned their attention to the microorganisms living on, in, and around the mummy. Their findings were published on June 3 in the journal Microbiome.
To conduct the study, scientists temporarily thawed Ötzi’s remains in 2019. The mummy, normally housed in a refrigerated chamber at the South Tyrol Museum of Archaeology in Bolzano, Italy, is kept at conditions designed to replicate the glacier that preserved him for centuries.
Researchers collected samples from melted ice, water surrounding the body, exposed internal tissues, and the mummy’s exterior. They also examined soil samples recovered during excavations and biological samples gathered during earlier studies.
The analysis revealed a diverse mix of ancient and modern microorganisms. Some appeared to have lived within Ötzi during his lifetime, while others likely colonized his remains after death or were introduced during conservation efforts.
“We found that the spray water used to keep the mummy humid has introduced a dominant signature of bacteria onto his external surfaces,” microbiologist Mohamed Sarhan told Reuters. “These modern introductions are effectively reshaping the mummy’s external microbiome—a consequence of conservation practices that was previously unrecognized.”
Among the most surprising discoveries were four strains of cold-adapted yeast associated with the glacial environment where Ötzi’s body was preserved. Genetic analysis suggested the yeasts entered the remains relatively soon after his death, around 3300 B.C., and survived in frozen conditions for millennia.
Researchers found evidence that one yeast strain, Glaciozyma, had become increasingly dominant over time. The findings suggest the organisms may have remained metabolically active under the mummy’s storage conditions, though some outside experts say additional evidence would be needed to confirm that conclusion.
“These yeasts have accompanied Ötzi on his long journey through the millennia,” said Frank Maixner, director of the Institute for Mummy Studies and a co-author of the study, per Smithsonian magazine.
The team successfully revived the yeast under laboratory conditions and used one strain to create a sourdough starter. After months of experimentation, researchers produced a loaf of bread from the ancient microorganisms.
“Eventually, we obtained a completely normal dough that rose within 24 hours − basically just like with ordinary yeast. We made some really good dough with it,” Sarhan said, per The Guardian. “I’ve never baked bread before – and it showed. So the result definitely had room for improvement. But as I said, these were our very first experiments.”
Researchers said the bread turned out well enough to encourage additional work, and they are now exploring other possibilities.
“We want to pursue this further and involve specialized research teams from the food sector in the process,” Sarhan said. “Bread is currently one of the obvious applications we’re considering; another is beer – we’ve already discussed this with experts from Weihenstephan.”
Scientists say the findings could help improve preservation techniques for frozen mummies and offer insights into how microorganisms adapt to extreme environments. The cold-tolerant yeasts may also have practical value in food production because they can remain active at lower temperatures.
“Yeasts that are active at very low temperatures can offer advantages in different areas,” Sarhan said in a statement, according to Smithsonian magazine. “If fermentation is possible at room temperature or even at refrigerator temperatures, energy can be saved since no additional heating is required. Furthermore, the yeasts could also be active during transport, meaning they could contribute to fermentation already on their way to the manufacturer.”
The researchers plan to continue studying the microorganisms and their potential applications while monitoring their effects on one of archaeology’s most important discoveries.
Ötzi is “the most important archaeological science finding of the 20th century and up until the present,” alpine archaeologist Patrick Hunt of Stanford University said, as reported by Smithsonian magazine. Preserving the mummy, he added, remains essential, making discoveries about its microbial inhabitants “vital to whatever interventions are needed.”
