How to descale an espresso machine — the five mistakes to avoid, and the steps that work
Breville the Descaler (pack of 4)
Researched by the WhyToBuyThis team · Updated November 2026 · How we choose
The short answer
Scale builds up wherever the machine heats water. The steps that work, the five mistakes that waste a descale, and the descaler Breville makes for its own machines.
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The short version
Tap water carries dissolved minerals, mostly calcium. Every time an espresso machine heats that water, a little stays behind as a hard, chalky crust called scale. It builds up where you can't see it, inside the heater, the pipes and the valves, and over time it narrows the path the water has to take. Descaling dissolves it, but only if the solution is the right one, reaches every path hot water takes, and is rinsed out afterwards.
This guide walks through the steps and the five mistakes that make a descale useless or leave you with a worse cup. Breville's instructions for the Barista Express are used as the worked example. Machines differ, some should not be descaled at home at all, and your own manual has the final word. The product shown here is the descaler Breville sells for its own machines.
Who it's for
A great fit if
- Breville machines on the pack's list: Barista Express, Bambino Plus, Dual Boiler, Oracle and Oracle Touch
- Anyone whose clean/descale light has come on, or whose buttons are flashing
- Hard-water homes, where scale builds up faster
- A routine: one common guide is every 1 to 3 months, depending on use
Skip it if
- Your manual names a different descaler: use that one
- Your manual says not to descale the machine at home
- The coffee tastes bitter but the water path is fine: that calls for cleaning (backflushing), not descaling
The five mistakes, and the fix for each
5. Waiting for a symptom
By the time the flow is slow or the steam is weak, scale has been growing for months. Machines usually tell you first: a clean/descale light on the Barista Express, flashing buttons on the Bambino Plus.
4. Guessing the descaler
Don't just reach for the vinegar. Brands recommend different solutions, so check the manual, then mix exactly as directed.
3. Leaving the water filter in
Breville's instructions say to take the water filter out of the tank before descaling. Lift it out, set it aside, and put it back when you're completely done.
2. Only descaling the coffee side
Scale forms everywhere hot water goes. Run the solution through the group head, the steam wand and the hot water outlet, then rinse with fresh cold water.
1. Thinking it's the same as cleaning
Descaling removes minerals from the water path. Cleaning, or backflushing, removes old coffee oils from the brew head. A machine needs both.
The catch
Descaling can't undo years of neglect, and a few machines shouldn't be descaled at home at all. If the manual says to leave it to a service centre, do that. And a perfectly descaled machine can still make bitter coffee if the brew head is dirty, because descaling doesn't remove coffee oils.
Skip the rinse and your next cup will taste of descaler. On the Barista Express, Breville's instructions run the rinse twice.
5 descaling mistakes, and the fix for each
Key specs
| What it is | Breville's own descaler, sold as a pack of 4 |
|---|---|
| Made for (per Breville) | Barista Express BES870, Bambino Plus BES500, Dual Boiler BES920, Oracle BES980, Oracle Touch BES990, plus several Breville kettles and tea makers |
| Barista Express mix | 1 packet dissolved in 1 liter of warm water |
| Before you start | Take the water filter out of the tank |
| Paths to run | Group head, then steam wand, then hot water outlet |
| After descaling | Rinse with fresh cold water; twice on the Barista Express |
| How often (a common guide) | Every 1 to 3 months, depending on use |
| Backflushing (a common guide) | About once a week with daily use |
Pack and compatibility from Breville's the Descaler product page; steps from Breville's Barista Express descaling instructions; intervals are a common retailer guide. Your own machine's manual has the final word.
How to descale, step by step
- 1Check the manual: confirm your machine can be descaled at home, and which descaler it names.
- 2Take the water filter out of the tank and set it aside.
- 3Mix the descaler exactly as directed. For the Barista Express that's one packet dissolved in 1 liter of warm water.
- 4Start the descale cycle the way your manual describes.
- 5Run the solution through all three paths: the group head, then the steam wand, then the hot water outlet.
- 6Rinse: refill the tank with fresh cold water and run it through again. On the Barista Express the rinse is done twice.
- 7Put the water filter back and refill the tank.
- 8Then clean the coffee side too: backflush the brew head if your machine supports it.
Have ready before you start
- Your machine's manual
- The descaler the manual names
- Warm water to mix it, measured as directed
- A container to catch the water
- Fresh cold water for the rinse
- A safe spot to set the water filter aside
Questions people ask
New to home espresso? Read our espresso buying guide first.
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