I have a coffee machine which can make espresso. It has a grinder and a brewing unit, and it takes water from a dedicated container, not from a tap. It looks mostly like this picture:


It detects scale accumulation (using just a counter of cups of coffee, I guess), and now it tells me I should run a descaling program using an original descaling liquid. I did this in the past, using a small liquid container which came with the machine. The descaling program runs about 30 minutes, doing weird things like sucking the liquid into the machine, heating it and spitting it back.

I imagine that such a descaling liquid is just a weak acid (maybe acetic or citric acid), chosen so that it will not dissolve the machine's innards. The size of the original container was about 250 ml, and the machine diluted it to about 1 L.

How can I prepare such a liquid myself? Which acid to use? Which concentration?

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    Vinegar is the normal solution Feb 26, 2020 at 15:17
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    I struggle to see the „hack“? This reads like a „how-to“ to me? And there‘s Coffee SE, which has for example this question.
    – Stephie
    Feb 26, 2020 at 17:32
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    @Stephie The hack I use is to just fill the whole coffee machine with vinegar and run it. I'm sure coffee SE, would not approve, but it works well enough for me. (I have really hard water so I do this every few months) Feb 28, 2020 at 3:53

2 Answers 2


i just use "baby bottle steriliser" crystals in little sachets from ebay. They cost literally pennies for a pack of ten or so. One packet per de-scale.

My delonghi magnifica S4200 ran for five years on these, till the AC power converter failed. It never scaled up. it got used a lot and so put up with an awful lot of de-scales

TOP TIP : put really hot water in the water tank with the crystals. This means that the coffee maker doesn't need to heat the water itself and also the crystals dissolve better, this makes the whole process an awful lot quicker.


My understanding is that it's more about a difference in pH than how to get that difference. Acid = lower pH, base = higher pH (than normal which is water)

Vinegar is a type of acid which is why it works like other acids.

Baking soda is a base. If an acid doesn't work, try a base, they are opposite in pH.

BTW: Mixing baking soda and vinegar doesn't do anything but put on a show, might as well just use water.

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