Sourdough made from yeast inside tummy of Europe’s oldest mummy

Friday, 5 June 2026

A replica of the Stone Age man Otzi who was discovered in the Alps in 1991 is on display in a museum in Magdeburg. Scientists have made bread using yeast found in his stomach.

Italy

Proving that scientists have a quirky sense of humour, a team of experts has extracted living yeast from the stomach of a 5300-year-old mummy and made sourdough bread from it.

The ancient yeast was located in the guts of Otzi the Iceman, Europe's oldest mummy, who was perfectly preserved by ice in the Italian Alps about 3200BC after he was shot in the back by an arrow.

Discovered in 1991 and now on display in Bolzano, Italy, the Neolithic hunter has yielded remarkable findings about life at the time, from his tattoos, diet, worn and aching joints and clothing to the type of feather flights he used in his arrows.

Thanks to an analysis of his stomach contents, scientists at Bolzano's Eurac Research institute have located four hardy types of yeast that can survive in sub-zero conditions.

“These yeasts have accompanied Otzi on his long journey through the millennia,” said Frank Maixner, a microbiologist.

The findings, published in the journal Microbiome, suggest that Otzi represents an unusual ecosystem in which ancient and modern microbial life may still be active.

Maixner said the yeasts did not originate in something Otzi ate, but were likely to have been in the snow and ice where he fell and entered his body after his death. His body has been kept at about minus 6C, roughly the temperature of the Alpine hollow in which it was found.

“It's possible they entered through his mouth and found a friendly environment in his body due to the nutrients there, but this is a process we need to understand better,” he said. “These yeasts like to grow at zero Centigrade and can also go into a dormant state.”

After three months of failed attempts, the team were able to produce an apparently tasty sourdough bread from the yeast and are considering making beer from it.

They also found a type of gut bacteria that has vanished from the stomachs of people living in industrialised societies but has been found among tribes in Africa and South America.

The discoveries follow attempts to recreate the sound of Otzi's voice after analysing his well-preserved vocal cords, as well as an examination of his deerskin quiver in which a coiled, 2m-long animal sinew cord, thought to have been a bowstring, was found.

However, the mystery of who killed him remains unsolved.

“It is fascinating how much information Otzi still holds,” Maixner said. “What we have achieved by studying his stomach would not have been possible 15 years ago, but since then technology has improved, meaning we can go on learning from him.”

The yeast strains may also have uses beyond archaeological curiosity and artisan baking. After Otzi was found in 1991, his body was initially handled like a modern corpse and treated with phenol, a chemical used to inhibit fungal growth. The study found that some of the yeasts were able to consume phenol, suggesting they could one day help to break down the chemical in contaminated environments.