'Ant yoghurt': Scientists study ancient fermentation method, warn against trying at home

Researchers from the University of Copenhagen and the Technical University of Denmark have explored an ancient yoghurt-making method that uses ants to ferment milk, according to a South China Morning Post report.

The study, published in the journal iScience, traces the practice to Turkey and the Balkans. The research team travelled to the Bulgarian hometown of co-author and anthropologist Sevgi Mutlu Sirakova, where locals demonstrated the tradition.

Lead author Veronica Sinotte from the University of Copenhagen said they followed local instructions and dropped four whole ants into a jar of warm milk. The jar was then placed overnight in an anthill -- a warm environment, providing the right conditions for fermentation.

Wood ants native to the region in which the study was conducted carry lactic acid and acetic acid bacteria, which contributed to the milk’s coagulation. Photo: Shutterstock

By the next day, the milk had thickened and soured, resembling early-stage yoghurt. 

Study leader Leonie Jahn from the Technical University of Denmark explained that wood ants carry lactic acid and acetic acid bacteria that help coagulate milk. Their natural acids lower the milk's pH, creating an environment where acid-loving microbes thrive.

Some of these bacteria are similar to those found in commercial sourdough, Jahn noted. Unlike modern yoghurts, which use only two bacterial strains, traditional methods create greater biodiversity, affecting taste and texture. The researchers, who tasted the yoghurt during their trip, described it as slightly tangy. 

Traditional Turkish yoghurt. Photo: Collected

"I hope people recognise the importance of community and maybe listen a little closer when their grandmother shares a recipe or memory that seems unusual," said Sinotte. "Learning from these practices and creating space for biocultural heritage in our foodways is important."

The researchers found that live ants worked best for fermentation, while frozen or dried ants failed to produce suitable bacterial cultures. They warned against trying the method at home, as live ants may carry parasites.

Chefs from Copenhagen's two-Michelin-star restaurant Alchemist later created dishes inspired by the traditional "ant yoghurt," including a mascarpone-like cheese, a special cocktail and a yoghurt ice cream sandwich named the "ant-wich."