Two things degrade an espresso machine, and both are invisible until they are advanced. Coffee oil oxidises and turns rancid on the group head, the basket and the burrs. Mineral scale from hard water deposits inside the boiler and the water passages. The symptom of both is the same: coffee that has gradually got worse for no obvious reason.
Every session
Purge and wipe the wand
Steam into the tray, then wipe the wand with a damp cloth. Milk left on a wand bakes on and then flakes into the next pitcher.
Rinse the basket
Rinse the portafilter basket and dry it. Old oil in the basket taints the next shot.
Brush the group head
With the machine off and the group cool enough to touch, scrub loose grounds out of the group and out of the gasket groove. A group head brush does this in fifteen seconds.
Empty the knock box
Spent pucks are wet and sugary. A box left for two days smells.
Water backflush
If the machine is rated for it, run a plain-water backflush cycle with a blind disc.
Weekly
Detergent backflushing is what reaches the passages behind the shower screen and the solenoid valve — places a brush cannot go. Use espresso-machine detergent, never dish soap: household detergents foam under pressure and can damage the machine.
Many thermoblock machines, and most lever and manual machines, must not be backflushed at all. Check the manual before the first detergent cycle — this is the one cleaning step that can damage equipment when applied to the wrong model.
- Clean the grinder chute and the burr chamber.
- Wash the drip tray and its grate.
- Rinse the milk pitcher cold, then wash it properly.
- Wipe the shower screen with a damp cloth.
Monthly to seasonal
Descaling removes the mineral scale that changes temperature stability and eventually restricts flow. The interval depends entirely on your water: hard water and daily use can mean monthly, soft water might mean twice a year. Filtering your water is what stretches the interval out.
Read the manual first
Some manufacturers void warranties on third-party descalers, and some machines should be descaled professionally.
Dilute as directed
Usually 1:10 to 1:20. A stronger mix is not better and can be aggressive to seals.
Cycle and soak
Run the solution through and let it sit for 20–45 minutes depending on how much scale there is.
Rinse thoroughly
Flush with multiple tanks of clean water. Residual acid tastes awful and is a genuine health concern.
Discard the first shot
Pull one and throw it away before you drink from the machine again.
Descaling solution is an acid. Wear gloves, ventilate the room, never mix it with bleach or another cleaner, and keep it away from eyes and skin. Store it out of reach of children and flush the machine thoroughly before drinking from it again.
The schedule, in one table
| Interval | Task | Tool |
|---|---|---|
| Every session | Rinse basket, purge and wipe wand | Cloth, warm water |
| Every session | Brush the group head | Group head brush |
| Every session | Water backflush (if rated) | Backflush disc |
| Weekly | Detergent backflush (if rated) | Cleaning tablets + disc |
| Weekly | Clean grinder chute and burrs | Grinder brush |
| Monthly–seasonal | Descale | Descaling solution |
| As needed | Replace group gasket and shower screen | Per machine manual |
The taste test
If your espresso has become bitter or dull and nothing about your technique changed, clean the machine before you change the recipe. It is the cheapest fix available.
Water quality drives most of this — see the water quality guide for why filtering is the change that reduces everything else on this page.
This guide covers hot water, steam, pressurised equipment and, in places, alcohol. Follow the instructions supplied with your own equipment, ventilate when you clean or descale, keep spirits out of reach of children, and drink responsibly.