How to Descale a Breville Barista Express (BES870), Step by Step

When the Barista Express Needs Descaling

Descale a Breville Barista Express (BES870) when its CLEAN/DESCALE light is solid. If the light is flashing, the machine wants the back-flush cleaning cycle instead, which is a different job. Descale mode starts with 2 CUP held, then POWER, and runs short timed passes through the coffee, steam and hot water circuits. You use one Breville descaling sachet in 1 L of water, then a 2 L rinse.

Breville's reason to bother: hard-water minerals build up "in and on many of the inner functioning components, reducing the brewing flow, brewing temperature, power of the machine, and taste of the espresso." The book doesn't give a calendar interval. The machine decides, and the light tells you.

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What You'll Need

None of Breville's espresso instruction books mentions vinegar, and the BES870 book names Breville's own powder. Use that, or Breville's descaler once the supplied sachet is gone.

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Step 1: Confirm It's Descale, Not Cleaning

The CLEAN/DESCALE light has two states.

• Solid: descale. Carry on with Step 2.
• Flashing: the cleaning cycle is due. Breville calls it "a back-flushing cycle", "separate from descaling". Skip to The Cleaning Cycle section below.

Descaling a machine that asked for a clean leaves the light flashing, which is the most common reason owners think descaling "didn't work".

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Step 2: Mix the Solution and Fill the Tank

1. Lift the water tank off by its handle and empty it.
2. Dissolve one Breville descaling powder sachet in 34 fl oz (1 L) of water.
3. Pour it into the tank.
4. Slide the tank back on and push down until it locks.

Keep the tank in place from here to the end. The book warns: "The water tank should never be removed or completely emptied during descaling."

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Step 3: Enter Descale Mode

1. Press and hold 2 CUP, then press and hold POWER, so both are held at the same time.
2. The machine heats first. The POWER light flashes the whole time.
3. It's ready when POWER, 1 CUP, CLEAN/DESCALE and HOT WATER/STEAM are all solid.

If nothing happens, check the STEAM/HOT WATER dial is at STANDBY, which the book says the machine needs before it will heat.

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Step 4: Descale the Coffee Circuit

1. Put a container under the group head.
2. Press 1 CUP. The button flashes while solution runs, for about 25 seconds.
3. When it stops, 1 CUP goes back to solid.

To stop early, press 1 CUP again. Only do that if you need to empty the container.

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Step 5: Descale the Steam and Hot Water Circuits

1. Point the steam wand into a container.
2. Turn the dial right, toward steam. Solution runs through the steam circuit for about 13 seconds.
3. Put a container under the hot water outlet.
4. Turn the dial left, toward hot water, for about 8 seconds.
5. Return the dial to STANDBY. Turning it to STANDBY also ends either pass early.

⚠️ Safety: what comes out of the wand and outlet is hot. Keep your hands clear and use heat-safe containers.

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Step 6: Repeat Until the Tank Is Empty

After one round of Steps 4-5, about half the solution (17 fl oz / 0.5 L) should be left. Run Steps 4 and 5 again until the solution is used up.

Don't walk away for long. The machine turns itself off after 5 minutes with no action in descale mode. If that happens, restart from Step 3. You don't need to mix new solution.

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Step 7: Rinse With a Full Tank

1. Remove the tank and rinse it thoroughly.
2. Fill it with fresh, cold water to the maximum, 68 fl oz (2 L), and lock it back in.
3. Repeat Steps 4 and 5 (coffee, steam, hot water) to flush any solution out of the machine.
4. Press POWER to leave descale mode. The lights switch off.

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Troubleshooting the Procedure

If the light still won't behave, our Breville descale light guide compares the Barista Express with the other Breville models.

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The Cleaning Cycle (Flashing Light)

1. Fit the 1 CUP basket, then the supplied cleaning disc, then 1 cleaning tablet.
2. Lock the portafilter in, with a large container under the spouts.
3. Fill the tank with cold water and empty the drip tray.
4. Press POWER to switch off.
5. Press 1 CUP and 2 CUP together, then also POWER. Hold all three for about 10 seconds.
6. The cycle runs about 5 minutes, with water flowing in bursts, and ends with 2 beeps.
7. Check the tablet has fully dissolved. If it hasn't, repeat.

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Make the Next Descale Rarer

• Change the water filter every 2 months. Breville says it "will reduce the need to descale the machine". Soak a new filter 5 minutes, rinse it, and set the date dial 2 months ahead.
• Change it more often in hard water, as the book recommends.
• Take the filter out if you use filtered or bottled water, per the book.
• Don't switch to demineralized or distilled water. Breville doesn't recommend it; it says it can affect the taste and "how the machine is designed to function".

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FAQ

How often should I descale a Barista Express?

When the CLEAN/DESCALE light comes on solid. The BES870 book doesn't set a calendar interval; the machine flags it. Changing the water filter every two months, or sooner in hard water, is Breville's way to make it come on less often.

Can I descale the Barista Express with vinegar?

The BES870 book doesn't mention vinegar. It specifies one Breville descaling powder sachet in 1 L of water, and a sachet comes in the box. We'd stick to that, or Breville's own descaler once it runs out, rather than guess at a vinegar dose.

Is this the same on the Barista Pro or Bambino?

No. The Barista Pro descales from MENU → DESCALE in three automatic stages. The Bambino Plus starts with 1 CUP + STEAM held while it's off, and the Bambino with 2 CUP + STEAM. Our Bambino Plus descaling guide covers the BES500 step by step.

Why does descaling take so little time on this machine?

The Barista Express descales in short passes: about 25 seconds through the coffee circuit, 13 through steam and 8 through hot water. You repeat them until 1 L is used up, then do it all again with 2 L of clean water. Most of your time goes into refilling and moving containers.

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Related Breville Guides

• Barista Express Not Working?: every BES870 light and what it means
• Breville Descale Light Won't Turn Off?: sequences for each Breville model
• Barista Express Leaking Water?: auto purge and the shower screen seal
• Breville Not Heating?: scale and Advanced Temperature Mode
• Barista Express & Pro Maintenance Schedule: cleaning, descaling, filter and burrs by prompt

Sources: Breville Barista Express BES870 Instruction Book (USCM V23).