Understanding Whiskey Fungus: Is It Harmful?

Main Points

Whiskey, particularly Jack Daniels, enjoys widespread popularity. Statista reports that the Jack Daniels brand sold around 5.4 million 9-liter (2-gallon) cases in 2021, even during the pandemic. Sales have consistently risen since 2013, highlighting its appeal. The Jack Daniels distillery in Moore County, Tennessee, not only produces this beloved spirit but also hosts a familiar fungus for those living near distilleries.

What Triggers Whiskey Fungus Growth?

Whiskey fungus, often referred to as distillery fungus, rum fungus, or warehouse-staining fungus, is scientifically named Baudoinia compniacensis. While it appears black, it is distinct from black mold, Stachybotrys, which is known to cause severe health problems and structural damage.

Here’s how it occurs: Once whiskey is distilled, it is stored in barrels for aging. During this period, about 2 to 5 percent of the alcohol evaporates. Depending on the volume of alcohol produced, this can lead to 200 to 1,000 tons (181 to 907 metric tons) of ethanol emissions annually.

These emissions, often termed the "angel's share," don’t quite ascend to the skies. When ethanol interacts with atmospheric moisture, it fosters a fungus that thrives on the sugar in ethanol—whiskey fungus. This fungus adheres to various surfaces, including buildings, trees, vehicles, and outdoor furniture.

How Can Whiskey Fungus Be Eliminated?

When spirits such as whiskey, Kentucky bourbon, Canadian whiskey, or Caribbean rum are distilled, distillery fungus emerges. While it can be temporarily removed, residents near the Jack Daniels distillery have found that pressure-washing with a water and bleach solution only keeps it at bay for a few months before it returns. Beyond the unsightly appearance, concerns linger about the long-term health and safety of living in a fungus-covered neighborhood.

Is Whiskey Fungus Harmful?

The answer is both yes and no. According to the Pediatric Environmental Health Specialty Unit (PEHSU), there isn’t enough evidence to confirm health risks linked to distillery fungus. However, PEHSU advises wearing protective gear like N95 masks, goggles, and gloves when cleaning contaminated surfaces. Vulnerable groups, such as children or individuals with conditions like asthma, should consult their doctors. The organization also recommends thoroughly washing or discarding any produce visibly affected by the fungus.

A Battle Against Whiskey Fungus Is Heating Up

Residents near the Jack Daniels distillery in Tennessee are frustrated by the widespread presence of whiskey fungus. They urge the distillery to install air filters to reduce emissions and even fund neighborhood pressure washing. One local has filed a lawsuit against the county to halt the construction of additional barrelhouses, securing a temporary injunction. Communities in Kentucky and beyond facing similar issues are closely monitoring the case.

A Jack Daniels representative stated that the fungus doesn’t cause permanent property damage, as it can be easily washed off, and poses no health risks. They refused to pressure wash neighboring properties due to liability concerns. Installing air filters is also off the table, as it could alter the whiskey’s flavor.

According to one report, some California distilleries and brandy aging warehouses have implemented systems to capture and burn off alcohol vapors. While this solution is likely costly, it could potentially resolve the whiskey fungus conflict.