How often should I descale my fully automatic machine?
With hard water and daily use every 4–6 weeks, with soft water every 2–3 months. The machine usually indicates it itself. Limescale narrows pipes, reduces heating power, and alters the taste.
Why that is
Tap water contains dissolved calcium and magnesium — the more it has, the "harder" the water is. When heated, some of these minerals precipitate as limescale (calcium carbonate) and settle on heating elements, pipes, and valves. Over weeks and months, these deposits narrow the machine's water pathways.
Consequences of calcification:
- Taste: Limescale alters the pH value of the brewing water. The coffee tastes flatter, chalkier, and loses its acidity and liveliness.
- Temperature: Limescale insulates the heating element. The machine takes longer to heat up and no longer reliably reaches the target temperature. Brewing water that is too cold = under-extracted coffee.
- Flow: Narrowed pipes slow down the water flow. The brewing process takes longer, making the extraction uneven.
- Lifespan: Heavy calcification can block valves, overload pumps, and in the worst-case scenario, irreparably damage the machine.
Guidelines based on water hardness:
| Water hardness | °dH | Descaling interval |
|---|---|---|
| Soft | under 8 °dH | Every 2–3 months |
| Medium | 8–14 °dH | Every 6–8 weeks |
| Hard | over 14 °dH | Every 4–6 weeks |
Most modern fully automatic machines have a built-in calcification sensor or a timer that automatically requests a descaling program. You should follow this prompt promptly — do not ignore or delay it.
Finding out your water hardness: The local water hardness is usually listed on your water provider's website. Alternatively, you can measure the hardness yourself using test strips (available at pharmacies or aquarium supply stores, starting around 2 euros).
In practice at Green Wall Coffee
Berlin has medium to hard water — if you use a fully automatic machine here, stick to the shorter interval.
You'll find us at Sophienstraße 27 in Berlin-Lichtenberg, Monday to Friday 8am–5pm and Saturday 10am–5pm.
Further reading
In-depth article: Drip Coffee Machine Guide
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- Can I use vinegar or citric acid for descaling?
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- How do I clean my coffee grinder? — Grinding & Grind Size
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All questions in this topic: Super-Automatic Machines