Scientists Bake Sourdough Using 5300 Year Old Yeast from Ötzi the Iceman
Finn's Take· TL;DR- Scientists isolated 5,300-year-old yeast from Ötzi the Iceman's remains and successfully baked sourdough bread after three months of cultivation work.
- The cold-adapted yeasts remained metabolically active in refrigerated storage since Ötzi's 1991 discovery, suggesting they colonized him shortly after death millennia ago.
- Potential applications include fermenting beer or bread commercially, and using the yeasts' phenol-consuming ability to help remediate contaminated environments in future biotechnology uses.
Ancient Microbes Come to Life
Ötzi the Iceman's skin and stomach are teeming with yeasts that infiltrated his remains shortly after his murder 5,300 years ago — and some may still be active, a new study reveals. After three months of effort "we had a very, very good sourdough," Sarhan said with a laugh. This remarkable discovery transforms our understanding of what happens to ancient remains, revealing them as complex living ecosystems rather than static archaeological artifacts.
More than 5,300 years ago — before the Egyptian pyramids were built — Oetzi was strolling through the Alps on the border of Austria and Italy when he was killed by an arrow in the back. He remained frozen in the ice until two German hikers stumbled across his mummified remains in 1991 in the northern Italian region of South Tyrol. Since then, his stunningly well-preserved remains have been kept at the same temperature — minus six degrees Celsius — as his icy tomb.
The yeast strains covering his body are adapted to cold environments, having stemmed from the Alpine glaciers Ötzi once called home. This means the spores have continued colonizing his mummified remains despite being stored in a refrigeration chamber at 21 degrees Fahrenheit (minus 6 degrees Celsius) following his discovery in 1991.
From Gut to Kitchen
The scientists then reproduced the gut yeast in a fridge. "If you tell anyone you have yeast, they immediately ask: can we use it for bread?" Sarhan said. So they tried to make a sourdough loaf. Initially it didn't work," the microbiologist admitted. But after three months of effort "we had a very, very good sourdough," Sarhan said with a laugh.
Genetic analysis revealed "DNA damage levels very comparable to the original microbes" in the Iceman's guts, suggesting the yeast entered his body soon after death, Sarhan said. "These yeasts have accompanied Oetzi on his long journey through the millennia," study co-author Frank Maixner said in a statement. The researchers published their findings in the journal Microbiome this week.
When the mummy was found in 1991, phenol was used to prevent fungal growth, but the yeast was able to consume the chemical, suggesting future use in breaking down phenol in contaminated environments. When asked if the scientists were considering using the yeast to brew beer, he responded: "It's on the list."
Living History
"His body hosts living, metabolically capable organisms that are actively responding to their environment," Sarhan told the Reuters news agency. "The cold-adapted yeasts are growing. Beyond yeast, analysis of Oetzi's microbiome revealed gut bacteria nearly absent in modern industrialised humans but still found among tribes in Africa and South America and in 3,000-year-old faeces from a salt mine in Hallstatt, Austria.
Evidence of ancient DNA damage in these yeasts strongly suggested they either laid dormant for 5,300 years or had descended directly from original yeast colonisers, the authors said in the study. However, some researchers remain cautious about the timeline. Nikolay Oskolkov, who previously discovered ancient fungus in the mummy's guts, cautioned that the yeast samples were only taken in 2010 and 2019. This provides "very little evidence that the yeasts have been multiplying over millennia," he said, adding that he believed they were "relatively recent colonists of the mummy's body."
Future Applications
These yeasts could be cultivated by fermentation industries in the future, such as for making bread or beer, Sarhan said. The discovery opens new avenues for biotechnology applications while highlighting the dynamic nature of preservation. However, it is currently unclear whether these microbes and the ancient yeasts are harming the preservation of his remains. Research is now needed to investigate this, Sarhan said.
This breakthrough demonstrates that ancient remains aren't frozen snapshots but evolving biological systems. As scientists continue studying Ötzi's microbial companions, they may unlock new understanding about preservation, ancient diets, and even develop novel applications for industries ranging from food production to environmental cleanup. The 5,300-year-old Iceman continues teaching us about life, death, and the surprising persistence of microscopic organisms through millennia.