It started in the second year. Thomas Chalmers, a computer analyst, began noticing a black dust settling on the patio paving behind his family's four-bedroom house in Bonnybridge, Stirlingshire. Then it was on the children's toys, then the garden furniture, then the walls. More than two decades and a 12-year lawsuit later, a judge at Scotland's highest civil court has ruled that the blackening, whatever its cause, is something the Chalmers family has to live with.
In a judgment reported on October 20, Lord Young, sitting in the Court of Session in Edinburgh, found in favor of Diageo Scotland Limited and granted decree of absolvitor, the Scots law equivalent of a final judgment clearing the defender, in the action Thomas and Gail Chalmers launched in 2014. The couple had argued that ethanol evaporating from whisky maturing in Diageo's nearby bonded warehouses was feeding a fungus that coated their home. The ruling ends, at least at this level, one of the longest-running and most unusual fights in the Scotch industry: a case about the angel's share.
A House on Woodlea Gardens and Nine Warehouses Behind It
The Chalmers bought their home in Woodlea Gardens in 2002, on an estate of more than 200 houses. Behind the estate sits a nature reserve, and beyond it, to the south-west, a bonded warehouse complex Diageo has operated since the early 1980s. There are now nine bonded warehouses on the site. The couple knew the warehouses were there when they bought the house.
What they say they did not anticipate was what came with them. Every cask maturing in those warehouses loses a small share of its contents to evaporation each year, the portion distillers have long called the angel's share. The Chalmers' case was that this vapor did not simply vanish. It drifted over the estate and fed a fungus that blackened the outside of their home, a sight they described as "unsightly and depressing."
The cleaning became part of family life. Gail Chalmers, a café manager, wanted to stay in the house but found the constant scrubbing exhausting. The routine went well beyond an occasional power wash; it included bleaching the exterior walls every few years.
Why Lord Young Ruled for Diageo
The legal theory was nuisance: that Diageo's use of its land had interfered with the couple's reasonable enjoyment of theirs. Under Scots law, that requires more than an irritation. The interference has to be more than a neighbor can reasonably be expected to tolerate. Lord Young framed the test in language long used in the case law, asking whether the discolouration amounted to "a material loss or inconvenience" or was "destructive of the ordinary comfort of life."
The judge accepted much of the couple's account
The ruling was not a dismissal of the family's experience. Lord Young described the question as a close one and conceded that the Chalmers had a point about the burden of keeping the house clean. "I accept that the pursuers describe a cleaning regime which goes beyond what would be expected for a residential house," he wrote. "In particular, the use of bleach on exterior walls every few years is unusual," he added.
But not that it crossed the legal line
On the central question, whether the blackening reached the level of an actionable nuisance, his answer was short: "I have concluded that it does not." He was not persuaded that the interference went beyond what a householder in an urban development next to an established industrial site should be expected to put up with. Where a business is using its land in a way that is common and usual for the area, he reasoned, an added aesthetic nuisance falls into the category of general annoyance a homeowner accepts when choosing where to live.
Whisky's economic weight was left out of it
Diageo had argued that the importance of whisky production to the Scottish and UK economies should count in its favor. Lord Young explicitly declined to factor that in. The ruling, in other words, does not rest on the idea that Scotch is too important to be held liable. It rests on the narrower finding that this particular interference, at this particular location, was not severe enough.
Twelve Years in the Court of Session
The case took a winding path to a full hearing. Diageo tried more than once to have it thrown out before the evidence was heard. In 2023, Lady Carmichael refused, ruling that "The averments of damage here are sufficient to permit inquiry." Diageo appealed to the Inner House, where a bench led by the Lord Justice Clerk, Lady Dorrian, rejected the challenge in early 2024. Diageo said at the time it would continue to defend the claim "vigorously," and it did.
Reports over the years put the family's claim at £40,000 in early coverage and later at around £100,000. Property value was a recurring battleground. The couple's case was that the staining had made their home worth less, while Diageo maintained that "Cosmetic discolouration has no impact on property value."
The Angel's Share, by the Numbers
The phrase sounds romantic, but the process is simple physics. Oak barrels breathe. As temperature and humidity swing through the seasons, a portion of the spirit inside passes through the wood and evaporates into the warehouse air, and from there through vents and walls into the surrounding atmosphere. In Scotland's cool, damp climate, the loss is commonly put at around 2% of a cask's volume a year. Multiply that across the tens of thousands of casks a single large warehouse complex can hold and the quantity of ethanol drifting off a site like Bonnybridge every year becomes significant.
That vapor is not visible, and it is not dangerous in the concentrations found outside a warehouse. But it is food. For one fungus in particular, the steady supply of airborne alcohol around a bonded warehouse is an ideal place to live.
Meet Baudoinia, the Fungus That Follows Whiskey
The organism at the center of the case is Baudoinia compniacensis, sometimes called warehouse staining fungus or simply whiskey fungus. It forms a sooty black crust on surfaces downwind of places that release ethanol vapor into the air, including distillery warehouses, bakeries and some industrial sites. It takes its name from Antonin Baudoin, a French pharmacist who studied the black growth on buildings around Cognac in the 19th century, and from Cognac itself, where the stains on cellar walls are so common that locals have long treated them as a sign of good brandy aging nearby.
Researchers have found that the fungus uses ethanol as a carbon source, which helps explain why it thrives near maturing spirits. It is generally described as a cosmetic and nuisance problem rather than a health threat to people, which is part of why cases like the Chalmers' turn on property value and amenity rather than injury. That distinction mattered here: the legal question was never whether the fungus is unpleasant, but whether it is unpleasant enough.
An American Problem, Too
Bourbon country knows this story well. Rickhouses in Kentucky and Tennessee hold millions of barrels, and every one of them gives up its own angel's share. In 2012, residents near distillery warehouses in Louisville filed lawsuits against several major producers over blackened homes, cars and trees. More recently, residents of Lincoln County, Tennessee, went to court in 2023 to challenge the construction of Jack Daniel's barrel warehouses near their properties, citing whiskey fungus among their concerns. The fights there have often turned on zoning and permitting as much as on nuisance law.
The Bonnybridge ruling is a Scottish decision under Scots law and has no binding force in an American courtroom. But the reasoning will sound familiar to anyone who has followed the U.S. cases: when a homeowner moves next to an established industrial operation, courts tend to set a high bar before treating the side effects of normal operations as legally actionable.
What the Ruling Means for Distillers and Their Neighbors
For the Scotch industry, which is expanding warehousing across the Central Belt and beyond, the decision offers some reassurance. A court that heard the full evidence accepted that the blackening was real and that the cleaning burden was unusual, and still found it did not amount to a nuisance. That will strengthen the hand of producers facing similar complaints, particularly where warehouses predate the homes around them.
It does not close the door completely. Lord Young's ruling was specific to the facts in front of him: a modern housing estate built next to a warehouse complex that had been operating for roughly two decades, owned by a family who knew the warehouses were there. A different location, a newer warehouse, or more severe damage could produce a different answer. Further appeal also remains a possibility, as it has throughout the case. No public statement from Diageo or the Chalmers family on the ruling had been reported.
For whisky drinkers, the case is a reminder that the poetry of the angel's share has a physical footprint. The two percent or so that rises out of a cask each year in Scotland's cool climate, and the larger share lost in a hot Kentucky rickhouse, has to go somewhere. In Bonnybridge, for one family, it went onto the patio, the toys and the walls, and a judge has now decided that is part of the price of living next door to the industry.
