Descaling kettles, coffee makers and coffee machines in rentals

Coffee is the first thing a guest makes in the morning, and a scaled-up machine is one of the most common reasons for complaints because it always shows up at the worst time: lukewarm coffee, a flow that takes three minutes, a kettle full of white flakes. Limescale doesn’t just appear out of nowhere, it builds up at a predictable rate that depends only on your water hardness. This guide gives you the real descaling frequencies and the method for each appliance.

How often to descale, depending on water hardness

The values on the right are those used in the CleanClac checklist, because in a rental you can’t afford to discover the problem on the day it becomes visible.

Finding out your water hardness takes two minutes: it’s published by town on the government water portal, and often shown on your bill. Above 25 °f, consider your water hard and follow the right-hand column without debate.

The kettle: the simplest and most visible

Limescale in a kettle is obvious: white patches at the bottom and flakes floating up into the cup. Guests immediately associate this with a dirty property, even though it’s just minerals.

The method:

1. Fill halfway with a mix of half water, half white vinegar.
2. Bring to the boilThen leave to sit for one hour with the kettle off.
3. Empty, scrubThe base with a soft brush if any patches remain.
4. Boil two or three times with clean waterDiscarding each time, so the next guest doesn’t get vinegar tea.

Citric acid powder, one tablespoon in half a litre, does the same job without the smell, and is the best choice if the property is occupied the same day.

The anti-scale filter inside the spout, found on many models, can be removed and brushed. Hardly anyone does this, but it’s what catches the visible flakes in the cup.

The filter coffee maker

Same principle, same product, but never use neat vinegar: always dilute half and half.

1. Pour the mixtureInto the reservoir, about half a jug’s worth.
2. Start a brew cycle halfwayStop, and let it sit for thirty minutes.
3. Finish the cycleThen run two cycles with clean water.

The filter holder, jug and lid are dishwasher safe. A brown deposit in the jug isn’t limescale but coffee tannin: it comes off with bicarbonate, not descaler.

Pump coffee machines: beware of vinegar

This is the most important point in this guide, and the one most often ignored. On an espresso, capsule or bean-to-cup machine, white vinegar is not recommended by most manufacturers: its acidity damages seals and some parts of the pump circuit. A machine descaled with vinegar for two years will eventually leak, and the warranty won’t cover it.

For these machines, use the descaler recommended by the manufacturer or a compatible citric acid-based descaler, and follow the built-in programme if your machine has one. Most recent models trigger a warning themselves: this is the best possible schedule, as long as someone sees it.

Three extra steps to take at every clean on these machines:

• Empty and rinse the used capsule bin or coffee grounds tray, where coffee starts to ferment in two days.
• Empty the drip tray, often full and never checked.
• Rinse the water tank and refill with fresh water, never water left from the previous stay.

The habit that halves limescale build-up

The best descaling is the one you don’t have to do. Two habits make all the difference in a hard water property:

• Never leave standing water in a reservoir or kettle between stays. Limescale forms as water dries, not while it’s circulating. Always empty at the end of cleaning.
• A filter jug provided for guests, with a cartridge changed every month. It protects appliances if guests use it to fill them, and it’s a real comfort bonus in very hard water areas.

The same logic applies to the washing machine, taps and shower screen, covered in Shower, bath, screen: tackling limescale.