How to Clean & Descale an Espresso Machine

The worst machine I ever opened on the bench was a three-year-old Gaggia that had never once been descaled. The boiler looked like the inside of a kettle in a limestone village – a crust of white scale you could scrape with a fingernail. The owner had brought it in because the shots “tasted weird.” They weren’t wrong.

Almost every machine that lands on my bench for a “flavour problem” or a “weak steam” complaint is really a cleaning problem in disguise. Coffee oils go rancid. Minerals build up. Neither is dramatic on any single day, which is exactly why people ignore it until the machine quits.

Here’s the whole routine I use, from the two-minute daily wipe to the deep descale, so your machine keeps pulling shots that actually taste like coffee.

Cleaning versus descaling – two different jobs

People blur these together, but they attack different problems and use different chemicals. Get them mixed up and you’ll waste product or damage seals.

Cleaning removes coffee oils and grounds from the parts that touch your puck – the group head, the shower screen, the portafilter, the baskets. That’s an alkaline detergent job, and the classic is a sodium-percarbonate powder like Cafiza (about $12 for a jar that lasts a year).

Descaling removes mineral scale – mostly calcium and magnesium carbonate – from the inside of the boiler and the water lines. That’s an acid job, using citric or lactic acid descaler. The two never do each other’s work.

Detergent cleans what the coffee touches. Descaler cleans what the water touches.

The daily and weekly cleaning that prevents most repairs

If you do nothing else, do this. The bulk of the failed group gaskets and clogged screens I replace come from machines that were never cleaned between drinks.

After every session

• Purge the steam wand for two seconds and wipe it with a damp microfibre cloth before the milk dries – dried milk is a nightmare to remove and a hygiene problem.
• Knock out the puck and rinse the portafilter and basket under hot water.
• Run a blank shot through the group for a second or two to flush grounds off the shower screen.
• Wipe the group gasket lip with a cloth so the next portafilter seats cleanly.

Weekly, on any pump machine

This is where backflushing comes in, and it’s the single most valuable habit for a home barista. You swap your normal basket for a blind (unperforated) basket, add about half a teaspoon of Cafiza, lock in the portafilter, and run the pump in short 5-second bursts.

The pump builds pressure against the closed basket, then the three-way valve releases it, pushing detergent backward through the shower screen and out the drain. Do five bursts, swap to a plain-water blind basket, and repeat five more times to rinse.

How to clean and descale an espresso machine on the right schedule

Timing is the part everyone gets wrong. Descale too rarely and you’re cleaning a crust; too often and you’re needlessly stripping the boiler with acid.

Your real variable is water hardness. I’ve measured customer tap water anywhere from 40 ppm on a good filtered supply to over 300 ppm in hard-water regions, and that difference alone can quadruple how fast scale forms.

A $10 pack of test strips takes the guesswork out. Dip one in your tap, match the colour, and pick your interval. Machines with a scale warning light (many Breville models) are a decent backstop, but they estimate from shot count, not your actual water.

The descaling process, step by step

The mechanics are similar across brands, though the button sequences differ. Mix your descaler to the label ratio – usually around 1 oz of solution per 34 oz of water for citric-based products – and fill the reservoir.

1. Empty the drip tray and remove any water filter from the reservoir. Descaler will ruin a resin filter.
2. Run about a third of the solution through the group head into a jug, then stop.
3. Run a burst through the hot-water and steam outlets so the acid reaches those lines too.
4. Let it sit for 10–15 minutes so the acid can work on the scale. This soak is the part people skip.
5. Run the rest of the solution through all outlets.
6. Rinse with at least two full reservoirs of clean water, flushing every outlet, until there’s no smell or taste of descaler.

That final rinse matters more than the descale itself. Leftover citric acid in the boiler will make your next three shots taste sharp and metallic, and people often mistake that for the machine being broken.

Model-specific descaling walk-throughs

Every brand hides the descale mode somewhere different, and getting the sequence wrong either aborts the cycle or, worse, leaves solution sitting in the boiler. I’ve written full walk-throughs for the three machines I service most.

If you own a Breville, the reservoir dance and the flashing-button sequence trip people up constantly – I cover it in the step-by-step for how to descale a Breville Barista Express, including how to clear the descale light afterward.

De’Longhi machines have their own quirks with the EcoDecalk cycle and the rotary dial timing, so the De’Longhi descaling walk-through covers the exact button holds that actually start the automatic cycle.

And the Gaggia Classic, which has no automatic mode at all, is a fully manual job – the Gaggia Classic descaling steps explain the run-and-soak rhythm that keeps that brass boiler clear.

Reading the signs before your machine tells you

You don’t need a warning light to know something’s due. The cup tells you first.

Scale usually shows up as shots that pull a touch cooler and taste sour or hollow, because the buildup insulates the boiler and drops your brew temperature by a few degrees. A steam wand that spits and struggles, or a machine that’s suddenly louder and slower to fill, is scale narrowing the passages.

Stale-oil problems taste different – a rancid, ashy bitterness that no grind adjustment fixes. When cleaning and dialling in both fail to bring back a sweet espresso, that’s your descale reminder.

Keep the two-minute daily wipe, the weekly backflush, and a descale on the schedule your water demands, and you’ll almost never see the inside of a bench like mine. The machines I never get to repair are the boring ones that get cleaned on time – and that’s exactly the goal.