How to Backflush and Descale Your Espresso Machine

An espresso machine is a pressurized boiler filled with hot water and coffee oils. If you don't maintain it, valves will clog, heating elements will fail, and your espresso will taste rancid.

Here are the two most important maintenance routines you must perform.

1. Backflushing (Weekly)

Every time you pull a shot, a 3-way solenoid valve opens to release the pressure, sucking a tiny bit of coffee oil and grounds back up into the group head. Backflushing cleans this out.

Note: You can only backflush machines equipped with a 3-way solenoid valve (most prosumer machines). Do not backflush a cheap appliance machine unless the manual explicitly says to.

1. Insert the Blind Basket: Swap your normal filter basket for the "blind" basket (a basket with no holes).
2. Add Detergent: Put a half-teaspoon of espresso machine detergent (like Cafiza) into the blind basket.
3. Run the Pump: Lock the portafilter in and turn on the brew switch for 5 seconds. You will hear the pump strain.
4. Release: Turn the brew switch off. You will hear a whoosh as the pressurized, soapy water is forced backwards through the group head and out the drip tray.
5. Repeat: Do this 5 times (5 seconds on, 5 seconds off).
6. Rinse: Remove the portafilter, rinse out the soap, lock it back in, and repeat the 5-on/5-off cycle with only clean water to flush the system.

2. Descaling (Every 3-6 Months)

Water contains minerals (calcium). When heated, these minerals bind to the metal inside your boiler, creating a chalky buildup called scale. Scale ruins heating elements and blocks valves.

Prevention is better than the cure. Use properly filtered, low-scale water so you rarely have to descale.

If you must descale:

1. Buy a Descaler: Use a citric acid-based descaler (like Dezcal). Do not use vinegar, as it leaves a lingering smell and can damage rubber gaskets.
2. Mix the Solution: Dissolve the descaler powder in warm water and pour it into your machine's water reservoir.
3. Fill the Boiler: Turn the machine on and run water through the group head and the hot water wand until the descaling solution fills the boiler.
4. Let it Soak: Turn the machine off and let it sit for 30-45 minutes. The acid will dissolve the scale.
5. Flush Completely: Empty the reservoir, wash it, and fill it with fresh, clean water. Run at least two full reservoirs of clean water through the group head and hot water wand to completely flush the acid out of the system.