How to Descale a Breville Barista Express

How often the light comes on depends on your water. With hard tap water it can be every month or two; with soft or filtered water, much less often. If shots start pouring slower, the steam wand weakens or the machine sounds strained before the light comes on, descale anyway.

1. 1

   Prepare the machine. Empty the drip tray and the water tank, and take out the water filter.

2. 2

   Mix the solution. Dissolve one descaling sachet in 1 L (34 fl oz) of water and pour it into the tank.

3. 3

   Enter descale mode. With the machine off, press and hold the 2-cup button, then press and hold Power at the same time. The machine heats up and the lights show it is in descale mode.

4. 4

   Set out the container. Put the 2 L container under the group head and the steam wand.

5. 5

   Descale the brewing circuit. Press the 1-cup button. Solution runs through the group for about 25 seconds.25 seconds

6. 6

   Descale the steam and hot-water circuit. Turn the dial to steam and let it run, then turn it to hot water and let it run, then return the dial to the centre.

7. 7

   Empty the tank. Repeat steps 5 and 6 until the tank is empty. Empty the container whenever it gets close to full.

8. 8

   Rinse. Rinse the tank well, fill it with fresh cold water to the MAX line and repeat steps 5 and 6 until it is empty again. Do a second rinse tank if you can still taste or smell descaler.

9. 9

   Finish. Press Power to leave descale mode, refit the water filter and pull one shot to discard before brewing normally.

The Barista Express heats water as it passes through a thermocoil, a narrow stainless steel pipe inside a heated block. Calcium and magnesium in hard water come out of solution when heated and stick to the inside of that pipe and the valves after it. Over time the narrower path slows the flow, makes temperature less stable and weakens the steam.

Descaler is a mild acid that dissolves those deposits. Running it through all three outlets matters: the group head, the steam wand and the hot-water outlet each have their own path, and scale in any of them causes problems.

Rinsing matters as much as descaling. Descaler is designed to be flushed out, and a tank of fresh water through every outlet removes both the loosened scale and the acid itself. If you skip it, the first few shots can taste sour or metallic, and leftover solution sitting in the system is not good for seals over time. That is why the manual's sequence ends with a full rinse tank, and why a second one is a sensible habit.

• Change the water filter every two months. Breville's manual says this reduces the need to descale.
• Use filtered or softened water. A jug filter or bottled water made for coffee cuts scale and often improves taste. Avoid distilled water on its own, which can make shots flat.
• Keep the cleaning cycle separate. Backflushing with a cleaning tablet removes coffee oils; it does nothing for scale. Do both on their own schedules.
• Use a proper descaler. Our cleaning tablets and descalers guide compares the options.
• Choosing between Breville models? Descaling is similar across the range; see Barista Express vs Barista Pro vs Express Impress for the bigger differences.

If the machine simply turns on normally, it was not off when you started, or Power was pressed before 2-cup. Switch it off, wait a few seconds, then press and hold 2-cup first and add Power while still holding it. The lights change to show descale mode once the machine has heated.

If the Clean/Descale light is still solid after descaling, the cycle usually ended early: the tank emptied before the coffee, steam and hot-water stages had all run, or the machine was switched off part-way through. Run the full sequence again with a rinse tank. If the light is flashing instead, the machine is asking for a cleaning cycle with a tablet, which is a separate job covered in our cleaning guide.

If flow is weak through one outlet only, for example the steam wand, run extra solution through that outlet before rinsing. A wand that still spits or barely steams after descaling may have a blocked tip; our steam wand not frothing guide covers how to clear it.

Know your water. Inexpensive hardness test strips tell you how quickly scale will build. Hard water means descaling every month or two even with the filter; soft or filtered water can stretch that to several months. Write the date on the tank or in your phone after each descale so you can see your own interval.