How to Descale Breville Barista Express (BES870): Complete Guide

A solid CLEAN / DESCALE light on the Breville Barista Express means the machine needs descaling. The BES870 procedure is not a single flush: you must run descaling solution through the coffee outlet, steam wand, and hot-water outlet, then repeat those stages with fresh water.

What you need

• One Breville descaling-powder sachet
• 34 fl oz (1 L) of fresh water for the descaling solution
• Up to 68 fl oz (2 L) of fresh, cold water for the rinse
• A heat-safe container that fits below the group head, steam wand, and hot-water outlet
• About 10–15 minutes without interruption

The U.S. BES870 manual specifies one Breville descaling-powder sachet dissolved in 1 L of water. If your market supplies a different approved product, follow its dilution label and the manual packaged with your exact model. Do not combine products or substitute a cleaning tablet for descaler.

How to descale the Breville Barista Express BES870

1. Prepare the solution. Dissolve one Breville descaling-powder sachet in 34 fl oz (1 L) of water, then pour it into the water tank.
2. Position a container. Place a heat-safe container where it can collect liquid from the coffee outlet. Be ready to reposition it below the steam wand and hot-water outlet.
3. Enter Descale mode. With the machine off and the dial at STANDBY, press and hold the 2 CUP button, then press and hold POWER at the same time.
4. Wait for the machine to heat. The POWER button flashes during heat-up. Descale mode is ready when POWER, 1 CUP, CLEAN / DESCALE, and HOT WATER / STEAM are all illuminated steadily.
5. Descale the coffee circuit. Press 1 CUP. The button flashes while solution runs through the group head for approximately 25 seconds, then returns to a steady light.
6. Descale the steam circuit. Move the container below the steam wand. Turn the steam/hot-water dial right to the STEAM symbol. This stage takes approximately 13 seconds. Return the dial to STANDBY when it stops.
7. Descale the hot-water circuit. Move the container below the hot-water outlet. Turn the dial left to the HOT WATER symbol. This stage takes approximately 8 seconds, then return the dial to STANDBY.
8. Repeat all three outlets. Roughly half the prepared solution should remain after the first pass. Repeat the coffee, steam, and hot-water stages to use the remaining solution. Do not leave the machine pumping after the tank stops delivering water.
9. Rinse the tank. Once the solution stages have finished, remove and rinse the water tank thoroughly. Refill it to MAX with fresh, cold water—up to 68 fl oz (2 L).
10. Run the complete fresh-water rinse. Repeat the coffee, steam, and hot-water stages with fresh water to remove descaler residue from all three circuits.
11. Exit Descale mode. Return the dial to STANDBY and press POWER. The mode has ended when the indicator lights switch off.
12. Final check. Refill the tank with fresh water, empty and rinse the drip tray, and run a short water-only flush before making coffee.

Three circuits you must rinse

Circuit	Control	Approximate active time	Where liquid exits
Coffee circuit	Press 1 CUP	25 seconds	Group head
Steam circuit	Turn dial right to STEAM	13 seconds	Steam wand
Hot-water circuit	Turn dial left to HOT WATER	8 seconds	Hot-water outlet

Complete all three circuits with descaling solution and again with fresh water. Rinsing only the group head can leave descaler inside the steam or hot-water path.

If Descale mode will not start

The machine starts normally

Switch it off and try the entry sequence again: hold 2 CUP first, then add POWER while continuing to hold both. Confirm that the dial is at STANDBY. Do not use the three-button cleaning-cycle combination.

The POWER button keeps flashing

Flashing during initial heat-up is expected. Wait until POWER, 1 CUP, CLEAN / DESCALE, and HOT WATER / STEAM are steadily illuminated before starting the first circuit.

The machine switches off before you finish

The BES870 exits automatically after about five minutes without an action in Descale mode. Re-enter the mode and continue with the stage that still needs to be completed, ensuring every circuit receives a full fresh-water rinse.

The CLEAN / DESCALE light remains solid

Confirm that you completed the fresh-water pass through all three circuits and exited by pressing POWER. Restart the machine once. If the solid light returns immediately, verify the exact model suffix and regional manual before repeating chemicals; button behavior can differ across Barista Express versions.

Little or no water comes from one outlet

Stop if the pump becomes unusually loud or an outlet produces no water. Confirm that the tank is full and fully seated. Severe scale or a separate blockage may require a water-flow diagnosis rather than repeated concentrated descaling cycles.

Descaling mistakes to avoid

• Do not confuse a flashing cleaning prompt with the solid descaling prompt.
• Do not put a cleaning tablet into the water tank.
• Do not mix descaler with vinegar, bleach, detergent, or another chemical.
• Do not skip the steam-wand or hot-water stages.
• Do not remove the tank while the pump is running.
• Do not make coffee until the full fresh-water rinse is complete.

When to stop and call for service

Stop if water leaks near the power cord, the machine trips an electrical circuit, you smell burning, the pump repeatedly runs without moving water, or the steam/hot-water dial cannot control flow. Turn the machine off, unplug it, allow it to cool, and contact Breville support or a qualified espresso-machine technician.

Official reference

• Breville BES870XL /A2 Barista Express instruction manual, Descaling section
• Featured photo: James Gose (jimmyweee), via Wikimedia Commons, licensed under CC BY 2.0.

Last verified against Breville’s U.S. BES870 documentation: September 12, 2026.