Whiskey fungus, answered

Whiskey fungus is a black, sooty fungus named Baudoinia compniacensis, known locally as bourbon fungus. It feeds on the ethanol vapor released as bourbon ages in barrels, the so-called angel's share, and grows on almost any outdoor surface near an aging warehouse.

Because you live near a source of ethanol vapor. Bardstown and Nelson County hold one of the densest concentrations of bourbon-aging warehouses in the world, and that vapor feeds the fungus that coats siding, roofs, fences, and concrete. Ordinary washing removes what you can see but not the growth itself, so it returns.

It has not been established by health authorities as a significant hazard to human health, and it is not the toxic black mold people worry about indoors. The real harm is to property: it stains surfaces, holds moisture against siding and wood, shortens the life of paint and shingles, and makes walkways slick.

Yes, as long as barrels age nearby. There is no permanent one-time cure while the ethanol source is still operating. The practical solution is periodic maintenance cleaning and remediation, usually once a year, which keeps your property clean and protects the surfaces underneath.

A pressure washer and bleach knock the black off for a while, but high pressure damages siding, wood, and shingles, and a surface rinse does not kill the growth at the root, so it returns quickly. This is why so many people feel they are fighting a losing battle with it.

Most homes in the area do well with an annual soft wash. Properties very close to a warehouse, or on the downwind side, may need it more often. A maintenance schedule is both cheaper per visit and less hassle than waiting until the house is completely black again.

For a typical home, a one-time cleaning generally runs from a few hundred dollars to around a thousand, depending on size, how heavy the growth is, and how many surfaces are involved. Recurring maintenance costs less per visit.

Usually not. Standard policies treat fungus and gradual staining as maintenance rather than a covered loss, so removal is typically out of pocket.

In Kentucky the active season runs from spring through fall. Freezing winter temperatures make soft washing ineffective and unsafe, so the coldest months are for booking, not cleaning. The smart move is to get on the schedule in winter so your home is cleaned first thing in spring, before the rush.

No. Baudoinia tolerates cold extremely well and simply waits out the freeze, then resumes as it warms. The black you see in February is the same coating you will see in spring, often worse. Winter does not clean your house, it just delays when you can.