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The short answer
To descale a Breville espresso machine: empty the tank, remove the water filter, dissolve descaling solution in 1 liter (34 fl oz) of water and fill the tank, then hold the 2-CUP button and press POWER to enter Descale mode. Once the POWER, 1-CUP, CLEAN/DESCALE, and STEAM/HOT WATER lights are all solid, run the coffee side with the 1-CUP button, then the steam and hot-water sides with the steam dial, repeat until the tank is empty, rinse the tank, and run the full sequence again with fresh water. The whole cycle takes 15–20 minutes, and Breville specifies one sachet of its descaling powder per 1 liter of water. You need to do this roughly every 2–3 months — sooner with hard water.
Quotable: Descaling removes mineral scale (limescale) from a Breville’s boiler and water lines with an acid solution; cleaning (backflushing with a tablet) removes coffee oils from the group head. They are different jobs on different schedules — a flashing CLEAN/DESCALE light means clean, a solid one means descale.
What you need: Urnex Dezcal powder or Breville’s own sachets (check the current price on a 4-use tub of Dezcal), 15 minutes of mostly hands-off time, and a large container under the group head. If your CLEAN/DESCALE light is flashing rather than solid, you need the cleaning cycle instead — see “Cleaning is not descaling” below and grab Breville BEC250 cleaning tablets.
Before you start: 3 things that trip people up
- Remove the water filter from the tank first. The Breville manual and Breville’s own descale tutorial are explicit: the filter comes out before you add descaling solution, or it will absorb the acid and be ruined. Also, Breville notes the water filter should never be removed or the tank fully emptied during descaling — take it out when you mix the solution, then leave the tank seated.
- Know your descaler. Breville’s instructions call for one sachet of its descaling powder dissolved in 34 fl oz (1 L) of water. Any citric-acid-based espresso descaler works — we keep Urnex Dezcal powder on the shelf because one tub covers many descales. Skip vinegar: it smells, lingers in the machine for dozens of shots, and Breville’s own guidance warns against it.
- Don’t confuse the lights. FLASHING CLEAN/DESCALE = cleaning cycle (coffee oils, tablet, once a week or so with daily use). SOLID CLEAN/DESCALE = descaling (mineral scale, acid, every 2–3 months). This single distinction answers half the confusion in Breville forums.
Step-by-step: descaling the Barista Express (BES870)
This sequence follows Breville’s BES870 instruction book, checked against the manufacturer’s current descale tutorial in September 2026. The same procedure applies to the Barista Pro, Touch, and Infuser with minor button-name differences — see the notes below the steps.
- Empty the tank, remove the filter. Take the water tank off, discard old water, and pop out the Breville water filter (if fitted) — it must not go through a descale.
- Mix the solution. Dissolve one sachet of Breville descaling powder (or the equivalent dose of a citric descaler like Dezcal — check the current price on a 4-use tub of Dezcal) in 34 fl oz / 1 liter of water, then pour it into the tank and reseat the tank on the machine.
- Enter Descale mode. Machine off. Press and hold the 2-CUP button, then press and hold the POWER button at the same time. The POWER light flashes while the machine heats; when POWER, 1-CUP, CLEAN/DESCALE, and the STEAM/HOT WATER indicator are all lit solid, it’s ready.
- Descale the coffee side. Press 1-CUP. The button flashes while the machine runs solution through the group head — Breville says about 25 seconds, though on a scaled machine it can run longer. Place a large container under the portafilter/spout to catch what comes out.
- Descale the steam side. Turn the steam dial right to the steam icon and let it run (about 13 seconds per the manual). Have a pitcher under the wand — it will spit solution.
- Descale the hot-water side. Turn the dial left to the hot-water icon (about 8 seconds). Container under the hot-water spout.
- Repeat until the tank is empty. After one full pass, roughly half the solution (about 0.5 L) should remain. Run steps 4–6 again to use it up.
- Rinse. Remove and rinse the tank thoroughly, fill with fresh cold water to max (2 L), and run the full step 4–6 sequence once more to flush residual acid.
- Exit. Press POWER — the LEDs switch off and you’re done. (Heads-up: Descale mode auto-quits after 5 idle minutes; if that happens, re-enter from step 3.)
Total hands-on time: about 15 minutes including rinse. Breville’s 25/13/8-second timings are for a healthy machine; heavy scale slows the flow, and a second full descale with fresh solution is the standard fix when flow is still sluggish.
How often should you descale?
Breville’s position: descale when the CLEAN/DESCALE light comes on solid, and expect to replace the water filter every ~2 months, which reduces how often descaling is needed. In practice, with daily shots:
| Your water | Descale every | Why |
|---|---|---|
| Soft (<100 ppm hardness) | 4–5 months | Little scale forms per liter |
| Moderate (100–200 ppm) | 2–3 months | The standard Breville cadence; matches the solid light |
| Hard (200+ ppm) | 6–8 weeks | Scale is the #1 killer of flow and temp stability |
Don’t wait for symptoms. By the time a machine brews slowly or the pump labors, scale is already coating the thermocoil, and Breville’s manual notes it reduces “brewing flow, brewing temperature, power of the machine, and taste of the espresso.” If you can hit the tank with mostly filtered or soft water, you stretch every interval. The best cheap insurance is genuinely boring: consistent water, a fresh tank, descale on schedule.
Cleaning is not descaling (and your light knows the difference)
Two separate maintenance jobs, two separate lights:
- Cleaning cycle — coffee oils. A flashing CLEAN/DESCALE light asks for the backflush-style cleaning cycle: insert the provided blind (rubber) basket, drop in one cleaning tablet, and run the cycle. Coffee oils rancidify on the shower screen and in the 54 mm baskets and are the usual culprit behind bitter, harsh shots on an otherwise healthy machine. Weekly with daily use is the norm. Tablets: Breville BEC250 cleaning tablets.
- Descaling — mineral scale. A solid CLEAN/DESCALE light (or nothing at all, if you’ve been ignoring it) asks for the acid cycle in the steps above.
Skipping the cleaning cycle is why a freshly descaled machine can still taste flat — the acid never touches coffee oils. Do both, on their own clocks.
Can you use vinegar?
We don’t recommend it, and neither does Breville. White vinegar is acidic enough to descale in the chemical sense, but it needs heavy rinsing — readers routinely report vinegar taste surviving multiple rinse tanks — and the manual’s descaling instructions specify Breville powder for a reason. Citric-acid descalers (Dezcal and Breville’s own sachets are both citric-based) dissolve the same scale at a friendlier pH, without the smell or the marathon rinse. check the current price on a 4-use tub of Dezcal — one tub outlasts a year of descaling for a single machine.
Which Breville machines this covers
The button sequence above is the Barista Express (BES870) procedure from Breville’s current manual. The Barista Express Impress (BES876) and other B-series machines use the same hold-2-CUP-then-POWER entry into Descale mode; display models (Barista Touch, Barista Pro) walk you through descaling from the settings menu instead of button gymnastics. Bambino and Bambino Plus use a similar descale-mode entry with their 1-CUP/2-CUP buttons — on the Bambino Plus the menu prompts the cycle. When in doubt, the descaling section of your model’s book matches this flow: remove filter, 1 L of solution, descale-mode entry, coffee-then-steam-then-hot-water, repeat, rinse.
Questions people actually ask
How do I know when to descale my Breville?
Two signals: the CLEAN/DESCALE light glowing solid (not flashing), or performance symptoms — slower pours, weaker pump noise, temperature drift. With hard water, descale on the calendar every 6–8 weeks rather than waiting for the light.
How long does a descale cycle take?
About 15–20 minutes including the rinse pass: 3–4 minutes to heat and enter Descale mode, then the 25/13/8-second coffee/steam/hot-water runs twice, once with solution and once with rinse water. Plan 30 minutes total on a heavily scaled machine.
What happens if you never descale?
Scale slowly chokes the thermocoil and valves: flow drops, brew temperature sags, the pump works harder, and espresso goes thin and sour before the machine eventually fails. Breville lists reduced flow, temperature, power, and taste as the direct consequences — and scale damage is the most common avoidable death of home espresso machines.
Do I descale with the portafilter in?
Locked in with the blind basket or a normal basket is fine — the solution exits through the group head into whatever container you’ve placed underneath. The manual’s only real warning is the tank: keep it seated and never fully empty it mid-cycle.
Keep your machine out of the repair queue
Descaling is the single highest-leverage 15 minutes in espresso machine ownership. Pair it with the weekly cleaning cycle and a reasonable water source, and a Barista Express will outlive your bean preferences. Shots still sour or bitter after a descale? The extraction diagnosis is in our sour vs bitter espresso troubleshooting guide. New to the machine altogether? Start with our beginners espresso machine guide, see how the Barista Express stacks against the Gaggia Classic Pro in our head-to-head comparison, or check the under-$500 field in our machine guide.
First published September 2026. Procedure verified against Breville’s BES870 instruction book and breville.com descale tutorial, September 2026. Filter-replacement and light-behavior details from the same manual. Descaler and tablet recommendations are ours, from kitchen use.