Descaling a bean-to-cup: how often, and with what

Limescale settles on the heating element and inside the lines. It insulates, so the machine works harder to reach the same temperature, and it narrows the flow. First you notice it in the taste, then in the speed, then in an error message.

In much of the Netherlands the water is hard enough that this is a matter of months, not years. Living in a soft-water area buys you slack, but not an unlimited amount.

Almost every bean-to-cup counts brews and calculates against the water hardness you set. That counter is more accurate than any schedule online, precisely because it accounts for your water and your usage.

So set the hardness correctly once — with the test strip in the box, not by feel — and descale when the machine asks. Not sooner, and certainly not later.

Vinegar and citric acid work, and they also attack rubber seals and aluminium. That is exactly why every manufacturer advises against them and why they void the warranty.

The maker's own branded fluid is usually expensive and rarely necessary; any descaler declared suitable for bean-to-cup machines does the same job. What you should not do is improvise with whatever is in the kitchen cupboard.

Descaling addresses the water path, not the milk. Milk residue is its own problem and a faster cause of death: a hose that is not rinsed grows something within days that you will not get out again.

Machines that rinse automatically after every drink take that work off you. If yours does not, rinse it yourself after use and take the parts apart weekly.

A machine left too long gives less volume and a flatter taste first. Then it blocks brewing until you run the programme — and by that point there is often so much scale that one round is not enough.

At worst the heating element cannot be cleared at all. That is a replacement rather than a repair, and on most machines it is the point where a new one is cheaper.