How Whiskey Can Cause Fungus To Spread

A black fungus that feeds on the alcoholic vapors released during American whiskey production has ended up coating towns near distilleries in a dark crust.

The fungus, known by its scientific name Baudoinia compniacensis, or as "whiskey fungus", grows on liquor vapors known as "the angels' share", released from the whiskey over the aging process.

The excessive growth of this black fungal layer has led to a local court in Lincoln County, Tennessee passing an order temporarily halting the construction of a new Jack Daniel's warehouse. Similar effects have been seen in Kentucky and in Ontario, Canada.

"In the case of this group of fungi (species of the genus Baudoinia), alcohol vapor stimulates fungal spores to germinate, it cues the growing fungus to protect its cells from abrupt temperature changes, and it provides a nutrient source for the fungus to eat," James A. Scott, a mycology professor at the Dalla Lana School of Public Health at the University of Toronto, told Newsweek. "All of this causes outdoor surfaces near ethanol-emitting processes to become encrusted with fungus over time."

"To be clear, the warehouses do not emit fumes (which are very fine particles like in smoke or air pollution) but rather alcohol vapor (which is just alcohol dissolved in air—no particles)."

This black and crusty fungus has been noted to grow in the vicinity of whiskey and other liquid vapors since at least the 1870s, when Antonin Baudoin, the director of the French Distillers' Association, described the distilleries in Cognac, France being coated by a "plague of soot". The fungus' scientific name, Baudoinia compniacensis, was named for Baudoin by Scott, who has been studying the fungus since 2001.

The fungus feeds on the ethanol in the vapors for their carbon nutrition in the same way that we use glucose sugars from the carbohydrates we eat, but their recorded growth rates suggest that they may also have another calorie source. The ethanol vapor has also been found to stimulate the formation of special heat-protective proteins that allow the fungus to live and grow on materials in more extreme conditions, such as in direct sunlight on roofs and house walls.

Scott said that he is not aware of any dangers posed to humans by the fungus, but that there has been minimal research into the effects on health.

"To my knowledge no research has ever been conducted to investigate whether this abnormal growth poses a health risk," Scott said. "For a few reasons, those of us who have studied its ecology do not think it is likely to be hazardous (at least if it remains undisturbed—pressure washing it from buildings should always be done using respiratory protection and eye protection)."

While not a danger to humans, it is damaging to property, trees and furniture. Scott told The New York Times that it can "wreck" the sides of houses and outdoor furniture, and even choke trees to death, with the only way to slow its growth being turning off its liquor vapor supply. The UAMH Centre for Global Microfungal Biodiversity has found that whiskey fungus can grow on a vast number of materials, including concrete, PVC plastic, galvanized roofing, and stone.

The unappealing sight of the fungus is not permanent however, as it can be removed using high-pressure water jets and bleach. It also appears to be a food source for a select few species: one study authored by Scott in 2007 and published in the journal Mycologia found that snails and slugs may graze on the mold.

Jack Daniel's has said that it cannot alter its air filtration processes to reduce the amount of ethanol vapor released into the environment.

"Existing independent and government research shows that there is no reasonably available control technology to prevent ethanol emissions without significantly adversely affecting the taste and quality of Jack Daniel's or any other aged whiskey," a statement from Jack Daniel's provided to the New York Post said.

Newsweek has asked Jack Daniel's for comment.

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