How to Descale a Coffee Machine: Instructions, Home Remedies and How Often

Limescale build-up is the most common reason a coffee machine suddenly takes longer to brew, gets louder, or simply stops tasting the way it used to. The good news: descaling regularly takes only a few minutes, costs almost nothing, and noticeably extends the machine's lifespan.

Why do coffee machines scale up?

Tap water contains dissolved minerals — mainly calcium and magnesium, which together determine what's known as water hardness. When heated, these minerals settle as limescale in the pipes, the heating element and the brewing unit. The harder the water in your area, the faster this happens. The consequences: higher energy use, because the heating element has to work against the scale, a slower brewing cycle, and in the worst case a damaged heating element.

How often should you descale?

How often you need to descale depends mainly on the water hardness where you live. The Verbraucherzentrale, Germany's consumer protection authority, distinguishes three hardness levels from soft to hard; your local water supplier can tell you the exact value for your area on request. As a rule of thumb: in hard-water regions, machines need descaling noticeably more often than in soft-water regions. Most automatic coffee machines have a built-in warning light for this anyway — on filter machines without an indicator, check the manual, which usually recommends an interval in weeks or by number of cups.

Descaling a coffee machine: step by step

1. Fill the water tank with descaling solution as recommended by the manufacturer — either a dedicated descaler or diluted citric acid.
2. On automatic machines, start the built-in descaling programme from the menu; on filter machines, run the solution through like a normal brew cycle, pausing briefly partway through so it can work.
3. Rinse at least two to three times with clean water afterwards so no descaler or citric acid residue remains in the system.
4. Clean removable parts such as the water tank, filter holder and drip tray separately by hand.

Citric acid or vinegar: what actually works?

For kettles and simple coffee machines without a brewing unit, diluted citric acid is considered safe by the Verbraucherzentrale: it barely smells, leaves no aftertaste, and is gentler on rubber seals than vinegar.

Automatic machines with a sensitive brewing unit need more caution: when citric acid is heated, it can form calcium citrate — a sticky substance that can clog fine internal tubing. For this reason, manufacturers explicitly recommend their own dedicated descaler over home remedies for these machines. Vinegar essence also works against limescale, but has a strong smell and attacks seals over time — many manufacturers explicitly advise against it in the manual.

Signs your machine needs descaling

– The coffee tastes more bitter or different than usual.
– Brewing takes noticeably longer than before.
– The machine is clearly louder while brewing.
– White deposits are visible in the water tank or viewing window.
– On automatic machines, the descaling indicator lights up.

When is a new coffee machine worth it?

If regular descaling no longer helps, there's often a deeper problem: a permanently damaged heating element, a clogged brewing unit, or seals that have become porous from years of scale and acid exposure. For older machines, it's often worth comparing against current models, which run more efficiently and come with automatic descaling programmes. Browse our range under Coffee Machines. For help choosing the right model, our service team is happy to advise you personally.