What is “whisky mould”?
The distinctive black staining often seen around spirit warehouses is caused by a fungus commonly called whisky fungus — scientifically Baudoinia compniacensis. It grows where ethanol vapour (“the angel’s share”) deposits on surfaces near ageing warehouses and bonded stores. The organism forms a sooty black coating on walls, timber, vehicles and nearby foliage.
Why it matters to distilleries and sites
- Aesthetic & reputational impact: Black staining can affect customer perceptions and the appearance of facilities.
- Surface degradation & maintenance costs: Over time, the film can trap dirt and may increase cleaning and maintenance needs for cladding, paintwork and equipment. Several operators report recurring cleaning requirements.
- Operational nuisance: Vehicles, signage and external storage can be affected, adding extra prep work for plant and logistics.
What causes whisky mould to grow?
Baudoinia thrives where low concentrations of ethanol vapour repeatedly settle on surfaces. Distilleries and bonded warehouses that release small amounts of ethanol into the air create the ideal local environment, especially in still, sheltered locations. Nearby bakeries and other ethanol-emitting operations can produce similar localised growth.
Effective cleaning approaches — what works in practice
Cleaning whisky mould requires a two-part approach: remove the existing growth and treat the surface to delay regrowth. Methods commonly used by professional teams include:
1. Mechanical removal (pressure, soft/steam cleaning)
- Pressure washing (on robust hard surfaces) can lift and remove the black film. Choice of pressure and nozzle is critical to avoid surface damage — some cladding and painted surfaces need low-pressure or soft-wash techniques first.
- Steam cleaning is excellent for timber, painted surfaces and around sensitive fittings because it combines heat and moisture with mechanical action and reduces reliance on strong detergents. Several specialist operators use steam where pressure could harm the substrate.
2. Chemical treatment (biocide / antifungal)
- After removal, a biocide or antifungal treatment is typically applied to kill remaining spores and reduce immediate regrowth. Products designed for exterior mould control (and approved for the surface in question) are used according to label instructions. Some specialist coatings or sealants can also reduce adhesion of regrowth for a time.
3. Combined approach
- Most successful commercial cleanings use a combination: mechanical removal (pressure or steam) followed by a biocide application, and targeted repeat visits to maintain results. This is the approach NEREC uses for sensitive distillery sites.
Recommended process (NEREC’s practical workflow)
- Site survey & sample — inspect affected areas, identify substrates (paint, timber, metal, masonry), and advise method. Drone surveys often speed up large warehouse assessments.
- Containment & risk assessment — set up drop sheets, protect drainage, and confirm run-off control. Discuss timing to minimise disruption.
- Mechanical cleaning — selected pressure/soft-wash or steam cleaning to remove surface film. Use the gentlest effective method to preserve finishes.
- Biocide application — apply a suitable, approved biocide/antifungal to reduce spores and regrowth. Follow manufacturer instructions and safety precautions.
- Rinse & finish — controlled rinsing and surface checks. Where appropriate apply protective coatings or recommend painting/repair work.
- Follow-up & maintenance plan — whisky mould returns where ethanol vapour persists; NEREC offers scheduled maintenance plans to manage recurrence and keep appearance controlled.
Why specialist contractors matter
Many general cleaning companies can remove simple moulds — but Baudoinia is unique: it recurs where ethanol vapours exist and often affects a wide range of surfaces and assets. Distilleries need teams who:
- Know how to choose the right mix of pressure, steam and chemicals for each substrate.
- Can manage health & safety, waste and environmental compliance.
- Provide repeat maintenance, not just one-off cleans — because the underlying vapour source means re-coating and ongoing checks are typically needed.
NEREC has experience across industrial and heritage sites in Scotland and offers bespoke plans for distilleries, bonded warehouses and nearby businesses.
How NEREC helps distilleries across Scotland
- Free initial drone or site surveys to map affected areas and propose a measured plan.
- Specialist steam & soft-wash teams for sensitive cladding, plus robust pressure options for stone and concrete.
- Approved biocide / antifungal treatments and advice on protective finishes.
- Scheduled maintenance contracts to keep sites presentable and reduce reactive cost.
- Full health & safety management, run-off controls and waste handling.
Practical FAQs
Q — Is whisky fungus dangerous to people?
A — Current public health literature does not identify Baudoinia as a significant human health hazard, but exposure during removal can irritate some people.
Q — How soon will it come back?
A — Regrowth timing depends on ethanol vapour levels. Where vapour release continues, reappearance can occur within months. Regular follow-ups slow the visible return.
Q — Can you treat vehicles, signs and consumer goods?
A — Yes. Vehicles and external furnishings can be cleaned with appropriate methods; delicate finishes may need soft cleaning and protective coatings.
Final notes — act early, protect assets
Distilleries and bonded warehouses are often proud local landmarks. Whisky mould cleaning preserves appearance, protects surfaces and reduces ongoing maintenance costs. Because Baudoinia thrives where ethanol vapour is present, long-term control is best handled by experienced teams that combine mechanical cleaning, targeted biocide use, and repeat maintenance.
NEREC Ltd provides whisky mould cleaning services across Scotland — from site surveys to steam/pressure removal, biocide treatment and scheduled follow-ups. If you’re managing a distillery, bonded warehouse or business affected by whisky mould, get in touch for a practical plan.
Contact NEREC Ltd
01224 399188
info@nerec.co.uk
www.nerec.co.uk