Descaling Coffee Machines & Hot Devices: Step by Step

Whether filter coffee machine, portafilter machine, hot water dispenser or kettle: almost every hot device in the catering sector has the same enemy – limescale. What starts as a thin grey film becomes a thick crust on the heating element, drives energy consumption up, distorts the taste and ultimately leads to device failure. Descaling is quick, affordable and easy to schedule. We show you how to recognise limescale build-up, how to descale properly and which intervals have proven effective in practice.

Why limescale is the number 1 device killer

When heating water, dissolved limescale precipitates and deposits preferentially where it is hottest: on heating elements, in boilers and instantaneous water heaters. Even a limescale layer of one millimetre acts like insulation and can noticeably increase energy consumption – the heating element has to get hotter to reach the same water temperature and overheats in the long term. Additionally, limescale deposits narrow pipes and valves, brew times lengthen, flow rates decrease. In coffee machines, taste is also affected: limescale changes extraction and makes even the best coffee flat and bitter.

Signs that reveal limescale

• The machine takes significantly longer to heat up or brew than before.
• White or grey deposits on outlet, nozzles or in the water tank.
• Louder operating noises, knocking or hissing when heating.
• Reduced flow, dripping rather than flowing outlet.
• Coffee tastes flat, bitter or changes despite using the same beans.
• Limescale particles or flakes in the hot water.

You should take action at the latest at the second sign – every week of delay allows the layer to grow further.

Determining water hardness: half the battle

How quickly a device limescales depends directly on water hardness. You can find out for free from your water supplier or within seconds with a test strip. As a rule of thumb: water is considered hard from about 14 °dH, very hard from 21 °dH. For hard water, a filter cartridge or softening system is worthwhile for high-quality coffee machines – it significantly extends descaling intervals and protects the boiler permanently. However, it cannot completely replace descaling.

Step by step correct descaling

• Preparation: switch off device and let cool, remove coffee residues and filter. Check manufacturer’s instructions for descaling.
• Prepare descaling solution: dose liquid descaler such as Descaler F1L according to label – or very easily with the pre-dosed Descaler portion sachets B15-30, which prevent dosing errors right from the start.
• Run through: pour solution into the water tank and start a brew programme or descaling mode depending on the device. For heavy limescale, let the solution act in the device for 15–30 minutes.
• Observe dwell time: do not shorten – the descaler needs time to fully dissolve the layer.
• Rinse thoroughly: run at least two to three full tank fillings of clear water through until no descaler residues remain in the system.
• Visual check: check nozzles, outlet and tank, wipe off external limescale spots – done.

The right intervals

Manufacturer’s instructions are always binding – a practical guideline for devices in daily commercial use is:

• Soft water (under 8 °dH): about every 2–3 months.
• Medium water (8–14 °dH): about every 4–6 weeks.
• Hard water (over 14 °dH): every 2–4 weeks or use a water filter.

Include descaling firmly in your cleaning schedule – what is scheduled is done. This applies to coffee machines as well as kettles, hot water dispensers, bain-maries and combi steamers.

Common mistakes

• Descaling with vinegar or acetic acid: damages seals and aluminium, leaves a taste.
• Too weak dosing – the limescale layer is only softened and hardens again.
• Insufficient rinsing after descaling.
• Descaling only when the device already shows faults.
• Installing water filter and then never descaling again – filters reduce limescale but do not eliminate it.
• Descaling hot devices – risk of splashes and aggressive vapours.

Conclusion

Regular descaling is the cheapest life insurance for your hot devices: lower electricity consumption, constant brewing temperatures, better coffee taste and significantly fewer repairs. Determine your water hardness once, set fixed intervals and use a professional descaler instead of home remedies – that’s all you need. Suitable machines for professional use can be found in our Coffee & Coffee Machines category, further care products under Cleaning Agents. Unsure about water hardness, dosing or device choice? Call us – we’re happy to advise you: +49 6724 2069393.