Limescale is building up in the machine or kettle
White chalky deposits appear inside the kettle or reservoir, heat-up takes longer, or flow through the machine has dropped.
Applies to: Espresso machine, Espresso, Filter coffee
Safety note
Descalers are acids and machines hold near-boiling water under pressure. Follow both the product's and the machine's instructions, never mix descaler with any other product, and never dismantle a pressurised component to reach scale.
Likely causes and adjustments
Try one adjustment at a time so you know what actually changed the result. Start with the first cause below — if it doesn't help, reveal the next.
Cause 1 of 3 · Commonly the cause
Hard water with no treatment
Do you know how hard your water is?
Test the water hardness or check your supplier's figure, then choose filtration or descaling frequency to match.
Related issues
Work it out
Interactive tools that take you through this one change at a time.
Learn the technique
Step-by-step guides to the skills this problem comes from.