A typical scenario (an illustrative situation drawn from common flood recoveries, not a review from any specific café)

The first customer after reopening lifts the cup, sniffs, and asks: "Why does the coffee smell musty?"

A small minimalist café beside the Ping River in central Chiang Mai is the dream that Mint and her partner saved for, and it has been open for three years. Its signature look is a cream linen sofa, sheer floor-length curtains, a hand-woven rug and the smell of freshly roasted beans that greets you at the door. In the flood season that year, the Ping overflowed and water stood about half a metre deep in the café for several days. They managed to lift the grinder and the bean stock to safety, but the sofa, the lower curtains, the rug, the wooden counter and the cabinets under the bar all sat in muddy water.

After the water receded, the two of them scrubbed the floor, washed the counter, laundered the curtains and dragged the sofa into the sun for several days. In photos, the café looked as beautiful as ever, so they announced the reopening on social media. Plenty of regulars came to show support, but some of the first customers were honest: they could smell damp the moment they walked in, and their favourite drink tasted slightly off.

That night Mint read a review that said, "Same atmosphere, but the café doesn't smell the same." She understood then that a café always sells its experience through the nose before the tongue. A musty smell hidden in the sofa and curtains, invisible to the eye, was quietly undoing everything they had built. And if the mold inside the furniture was left alone, it might affect more than the aroma. It could affect the health of customers and staff too.

Why cafés are more sensitive to flooding than most shops

Coffee shops and cafés have three features that make flood damage worse than it first appears. First, the décor is designed to feel soft and warm: fabric sofas, cushions, throw pillows, curtains, rugs and timber walls, all of which absorb water and odours extremely well. Second, the core products, including roasted coffee beans, tea powders, milk and baked goods, readily pick up smells from their surroundings, so a musty room can end up in the cup. Third, a café combines food preparation, customer seating and a plumbed water supply feeding the espresso machine. A flood therefore hits food hygiene, atmosphere and expensive equipment all at once.

What really causes the musty smell and what hides in a café

Mold in upholstered furniture and fabrics. The foam inside sofas and seat pads holds water deep inside. Sun drying makes the fabric surface feel dry, but the inner layers can stay damp for days. Molds such as Aspergillus, Penicillium and black molds grow in that layer and release musty volatile compounds every time someone sits down and compresses the cushion. The lower part of curtains and rugs behave the same way.

Bacteria from floodwater and drains. Floodwater is often contaminated with sewage, carrying enteric bacteria such as E. coli into the shop, especially under the bar, around the glass-washing sink, floor drains and storage cabinets. If cleaning is not thorough, germs can move onto cups, spoons and staff hands, leading to diarrhoea, stomach pain or vomiting among customers.

Risks in the coffee machine's water system. If the flood reached the water filter, holding tank, inlet pipes or the machine itself, the whole system must be checked by a qualified technician: filters replaced, lines flushed and the electrics inspected before use. This is both an electrical safety issue and a question of the water that goes into every drink. It is a job for the coffee machine technician. Neither ozone nor wiping with disinfectant can replace it.

Odours trapped in porous materials. Timber walls, wooden shelves, terracotta pots and other porous décor absorb odour molecules from muddy water and release them slowly, especially on hot days or when the air conditioning is running.

Who is most affected

Customers with allergies, asthma or sinus problems may sneeze, feel congested, get itchy eyes or feel tightness in the chest after sitting in a café full of mold spores. Young children with their families, pregnant women, older adults and people with chronic illnesses are more sensitive than most. Baristas and staff, who spend all day inside, receive the longest exposure. Anyone who waded through water to move stock and later develops fever, headache or calf pain should see a doctor promptly, because these can be symptoms of leptospirosis.

What café owners are up against

Health. Customers or staff who are sensitive to mold may develop respiratory symptoms, and if hygiene behind the bar is not fully restored, diarrhoeal illness can spread through cups and utensils.

Money. Most cafés are small businesses with limited cash flow. Replacing beans that absorbed odours, repairing the espresso machine, replacing a sofa or a full set of curtains, and losing income while closed add up to a heavy burden. Recovering in the wrong order and having to repeat work only adds unnecessary cost.

Time. Every day the café is closed, regulars may get used to another shop. Every day it is open with a musty smell is a lost chance to win people back.

Online reputation. Cafés live on reviews, photos and word of mouth. A few comments mentioning a musty smell or poor cleanliness can stay on review platforms for a long time and sway new customers.

Family and team. Many cafés are family businesses or run by couples who invested all their savings. The stress of the damage, plus worry about reviews and sales, weighs on owners and on staff who need their income to repair their own flooded homes.

Why the usual fixes do not work

Sun-drying sofas and cushions. Sunlight dries the fabric surface and reduces some odour, but the inner foam stays damp and moldy. The smell comes straight back once the sofa returns to an air-conditioned room.

Spraying perfume or lighting scented candles. In a café, foreign fragrance directly competes with the coffee aroma. Customers who come for good coffee notice immediately, and fragrance does nothing about the mold causing the problem.

Wiping everything with bleach. Chlorine leaves a strong smell that clashes with coffee, fades fabrics and timber, and can leave residue on food-contact surfaces if not rinsed properly. Crucially, it cannot reach the inside of a sofa or the air.

Using charcoal or baking soda to absorb odours. These may help a little in a small cupboard, but they are not enough for a whole café and do nothing about microbes.

Reopening first and fixing it later. This is understandable when income is urgent, but first impressions after a flood are precious. Opening while the café still smells musty may cost more customers than staying closed for one or two extra days to finish the job properly.

WHD ozone treatment: giving your café its clean air back

World Health Disinfection (WHD) offers a Residential and Building Ozone Disinfection service for homes, condominiums, hotels, offices and commercial spaces, including cafés and coffee shops. Ozone (O3) is a strongly oxidising gas. Released in a closed café, it penetrates the fabric of sofas, curtains and rugs, furniture crevices and the space above the ceiling. It destroys the cell structures of viruses, bacteria and molds and breaks down musty odour molecules, then reverts to oxygen (O2) without leaving chemical residue or any foreign smell that would interfere with the coffee.

According to the test results certified for the company by Thailand's Department of Medical Sciences and Intertek (UK), the WHD system eliminates 99.99% of viruses, bacteria and mold. Details are on the certification page.

Know the limits. Ozone treatment happens after mud removal, washing and drying. It does not replace cleaning food-contact surfaces, it does not replace a technician's inspection and flushing of the coffee machine, and it cannot rescue furniture whose foam has rotted. Badly damaged furniture should be re-foamed or replaced.

How ozone treatment works in a café

1. Survey the shop. The team looks at seating areas, the bar, storage, restrooms and the spots where the smell is strongest, then plans zones and timing.
2. Remove all ingredients and food. Coffee beans, tea, milk, syrups, pastries and ice must leave the premises, because ozone is an oxidiser that can affect the aroma and oils of roasted beans.
3. Switch off machines and electrical equipment as the team advises, and cover any equipment the manufacturer recommends protecting.
4. Everyone leaves. No people, pets or plants inside, including a café cat or decorative plants that are part of the design. Close doors and windows tightly.
5. Release ozone. Equipment is sized to the shop. A cycle typically takes about 30 minutes per zone depending on size and odour level.
6. Contact time. Ozone is given time to work its way into fabrics and crevices.
7. Rest and ventilate. The shop is left while ozone reverts to oxygen, then ventilated for the period the team advises before anyone goes back in.
8. Prepare to reopen. Clean and sanitise food-contact surfaces as usual, bring ingredients back, and brew test cups to check aroma and taste before serving.

Espresso machine, grinder and bar: what to do before ozone day

Espresso machine. If water reached the machine or its base, do not plug it in to "see if it works". Have a technician trained by your supplier check the electrics, boiler, pump and valves before any use.

Water filtration and inlet lines. Replace every filter cartridge that was submerged and flush the lines according to the manufacturer's instructions. Water is the main ingredient in every drink you serve.

Grinder. Beans left in the hopper and grounds left in the burr chamber may already have absorbed musty odours. Discard them and clean the grinder according to the manual.

Refrigerators and display chillers. Throw away food that sat inside during a long power cut. Wash the unit with a cleaning solution, dry it and check the door gaskets, which often collect mold.

Sinks, drains and under-bar cabinets. Remove all mud, check drains for trapped wastewater and tear out swollen plywood. These cabinets are the mold source closest to your cups and utensils.

Bean stock in storage. Bags that never touched water but sat in a damp café for days should be test-brewed and smelled before you decide to use them, because roasted coffee is highly sensitive to ambient odours.

10 reasons cafés should use ozone before reopening after a flood

1. Bring back the coffee aroma. Once the musty smell is gone, fresh roast becomes the first thing customers notice again.
2. Reach the inside of sofas and cushions, where wiping and sun-drying cannot go.
3. No chemical smell to spoil the taste. Ozone reverts to oxygen. Read more about ozone and chemical residue.
4. Tackle mold in curtains and rugs, the biggest odour source in a cosy-style café.
5. Reduce discomfort for allergic customers, so guests and baristas can sit comfortably.
6. Short treatment time. Around 30 minutes per zone, done on your day off or overnight, with our ozone service for shops and buildings.
7. Tested by credible bodies, according to the test results certified for the company by the Department of Medical Sciences and Intertek (UK).
8. Cheaper than replacing everything. Furniture that is structurally sound and fully dry has a good chance of staying in service.
9. Pairs with surface disinfection. Ozone jobs of 15,000 baht or more receive a free medical-grade disinfectant spray.
10. Protect your reviews and reputation. Reopen with confidence. Talk to us via the ozone disinfection service page.

Example case: a shophouse café in Hat Yai

Example case (an illustrative scenario to explain the process, not a verified review)

Beam runs a café in a two-storey shophouse in central Hat Yai, Songkhla. The ground floor, with the bar and some seating, flooded almost knee-deep. Upstairs, with sofa seating and a space for brewing workshops, stayed dry, but the musty smell from downstairs rose up the stairwell until the whole café smelled the same.

Beam started by calling her machine supplier's technician to inspect the espresso machine and replace the water filters. She threw out all beans and ingredients from the ground floor, tore out the swollen under-bar cabinets, sent the downstairs sofa cushions with damaged foam to be re-foamed, washed the curtains and rugs, and ran dehumidifiers for several days. Once everything was dry, she booked the WHD team for a Monday night when the café was closed, covering the ground floor, the stairwell and the upper floor.

The next morning, after the rest and ventilation period, Beam roasted a fresh batch and brewed test cups. The clearest change, she says, was walking in and smelling coffee again, not floodwater. When she announced the reopening, she described what had been done in plain language, and several regulars told her that honesty made them feel confident about coming back.

Talking to customers after the flood

How you communicate your reopening matters almost as much as the cleaning itself. Customers in flood-hit towns know what the water did to their own homes, so a post that simply says "we're back!" can raise more questions than it answers. A short, factual note works better: which areas were affected, that damaged furniture and ingredients were replaced, that the coffee machine was inspected and the water filters changed, and that the café was treated after drying. Avoid exaggerated claims such as "100% germ-free", which no honest business can promise. Instead, invite regulars to come and smell the difference for themselves. If a review mentions an odour you missed, reply politely, thank the customer and fix the source, because a visible, responsive owner rebuilds trust faster than a perfect photo ever will.

It also helps to think about the months ahead. Flood seasons in Thailand tend to repeat, so use this recovery to make the next one easier. Mount the espresso machine and grinder on higher counters where possible, keep bean stock on upper shelves in sealed containers, choose seat cushions with removable, washable covers, and hang curtains so they stop a little above the floor. Keep a short list of your machine technician, your insurer and your cleaning and disinfection contacts somewhere you can reach from your phone. None of this stops water from coming in, but it can turn a two-week closure into a few days.

Café flood recovery checklist

Days one to three after the water recedes

• Switch off the main power and do not run the espresso machine, grinder or any flooded fridge until a technician checks it.
• Photograph all damage for insurance and assistance claims.
• Discard food, milk, pastries and beans that touched floodwater or sat in a fridge through a long outage.
• Wear boots, rubber gloves and a mask while clearing mud.

While washing and drying

• Remove mud and wash floors, walls, counters and cabinets with a cleaning solution, then disinfect.
• Launder curtains, cushion covers and removable rugs. Re-foam or replace furniture whose foam sat in muddy water for a long time.
• Run fans and dehumidifiers, following general public health advice to clean and dry within 24 to 48 hours to limit mold.
• Clean air conditioners before switching them on.
• Have a technician inspect the coffee machine, replace water filters and flush the water system.

Ozone day

• Remove beans, ingredients, food, plants and pets from the café.
• Everyone leaves and returns only after the rest and ventilation period.

Before serving again

• Wash and sanitise all cups, utensils and food-contact surfaces.
• Brew several test cups to check aroma and flavour.
• Tell customers honestly how the café was restored.
• If staff develop fever, calf pain or diarrhoea, they should stay home and see a doctor.

Frequently asked questions

1. Will a flooded sofa be usable again after ozone?

It depends on its condition. If the frame is sound and the foam is completely dry, ozone does a good job on the remaining odour and microbes. If the foam sat in muddy water until it rotted or collapsed, it should be re-foamed or replaced.

2. Do we really have to take the coffee beans out?

Yes, all of them. Ozone is an oxidiser that may affect the aromatic oils of roasted beans and other food ingredients in the café.

3. Does ozone clean the inside of the espresso machine?

No. The machine's water system, boiler and filters must be inspected, flushed and serviced by a technician according to the manufacturer. Ozone deals with air, odours and microbes in the café space.

4. How long do we need to close?

Typically about 30 minutes per zone plus rest and ventilation time. Most cafés schedule it on their weekly day off or after closing.

5. Does the café cat have to leave too?

Yes, along with every plant. The treated space must be empty of people, pets and plants and may only be re-entered after the rest period.

6. Will the musty smell come back?

If the moisture source remains, such as damp walls or a leak, mold can return. Dry the café fully and fix leaks first, then ventilate regularly and clean fabrics on a schedule.

7. A staff member who waded through water now has a fever. What should we do?

They should stop work and see a doctor straight away, mentioning their flood exposure, especially with high fever, headache or calf pain. Nobody should prepare food or drinks while they have diarrhoea.

Let customers walk in and smell coffee, not floodwater

Talk to WHD about treating your café on your day off, so you can reopen with confidence.

Book Café Ozone Treatment

Call 065-556-6294 · LINE @whd268 · worldhealthdisinfection@gmail.com

Related services and reading

• Residential and Building Ozone Disinfection
• Ozone cleaning service
• How ozone helps reduce chemical residue
• Certification documents

References

• CDC: Floods and Your Health
• World Health Organization fact sheets