Whiskey maturation emissions feed black fungus growth near Irish distilleries
A fungus called Baudoinia, commonly known as whiskey fungus, thrives on surfaces near Irish whiskey maturation warehouses, fueled by ethanol evaporating from casks. This black patina, often mistaken for soot, appears on walls, roofs, and trees, and its spread to nearby properties is under investigation. Researchers at Dublin City University are studying whether the fungus poses any health risks, though none have been confirmed yet.
Baudoinia has been documented near spirit maturation sites for over a century, with the earliest observations tied to cognac facilities in France before similar growth appeared in Scotland, Canada, and the United States. The fungus exists naturally at very low levels but flourishes when airborne ethanol condenses in moisture, creating a specialized ecological niche around warehouses. Ethanol dominates the volatile organic compound emissions from whiskey production, with over 90 percent released during the maturation phase. These emissions also contribute to ground-level ozone formation, a separate environmental concern from the visible fungal discoloration.
In 2022, Ireland's Environmental Protection Agency investigated complaints about black staining on homes near the Midleton distillery in County Cork. While Baudoinia was confirmed on a whiskey warehouse, testing did not detect the fungus on any of the three nearby residential properties sampled, leaving questions about its spread to populated areas unresolved.
This story could affect residents living near distilleries and maturation facilities, who may face property discoloration and uncertainty about potential health effects. The whiskey industry, a major Irish export valued at over €930 million annually, may need to address public concerns while balancing economic interests. Researchers have not confirmed any health risks, but ongoing investigation at Dublin City University could shape future regulations or industry practices if findings emerge.