What does is mean to descale a Tassimo machine?

The descaling process on a Tassimo machine refers to removing any limescale that has built up in the internal workings of the brewing system. As of 2015, a Tassimo coffee brewer is fitted a red light that indicates when the machine needs descaling.

A Tassimo coffee machine that is not descaled regularly is more likely to fail before the end of its product lifetime. The taste of any drinks brewed through a machine that has scale buildup also tends to be negatively affected. On a Tassimo coffee machine, the descaling process can be automatically initiated by inserting a service disc and descaling tablet.