Backflushing an e61 espresso machine is an important part of routine maintenance and cleaning to ensure quality espresso.
Why do we need to backflush the machine?
Backflushing the machine has two key purposes; to clean in behind the shower screen and remove accumulated residue where fresh brewing water will flow, and to clean the accumulation of coffee residue from the infusion and drain valves in the bottom "leg" of the brewing group. Backflushing the machine helps to eliminate bad taste associated with accumulated coffee residue while also prolonging the life of valves in the brewing group by removing contaminants.
How does backflushing work?
Backflushing the machine works by forcing cleaning product throught the parts of the brewing group where coffee residue tends to accumulate as part of the brewing process. The unique feature of the e61 brewing group is the ability of the machine to "release" excess pressure once espresso has been delivered. This release of pressure results in coffee containing water flowing back through the shower screen, through the infusion valve, and out of the drain valve. With each extraction cycle, coffee resude is deposited along this parthway. Backflushing works by repeating the brewing cycle, without coffee, to force clean water through this exhaust pathway; cleaning product is introduced to dissolve the accumulated coffee residue.
How often should you backflush the machine?
For the home or small office user, we recommend that ideally you should backflush the machine without cleaning solution (water only) every day and backflush with cleaning powder once per week. In a cafe or a large office where you are using kilos of coffee per day then the machine should be backflushed with cleaning powder daily.What you will need to backflush your espresso machine
Rinse the group and remove excess coffee particles
Rinse an loose coffee grounds from around the grouphead. Insert the portafilter into the group and activate the pump into water flows. As water flows, move the portafilter handle from side to side engaging and releasing the portafilter from the group. Hot water will flow around the body of the portafilter rinsing stray coffee particles from around the shower screen and group head seal.
Clean the group
Remove the portafilter and fit the blank filter basket (if available) or insert the backflushing disc into the bottom of the double filter basket. At this point if you are using powder detergent apply a small amount (as per the manufacturers recommendations) into the portafilter.
Lock the portafilter into the brewing group very securely. Activate the pump and wait for the pump pressure to build; if you have a pressure gauge fitted to your machine you should see a pressure of 9+ bar, if you dont have a pressure gauge you should be able to hear a change in the noise emitted by the pump as it strains. After 1-2 seconds of maximum pressure, deactivate the pump; you will notice a damatic exhaust of pressure from the drain valve at the bottom of the group head leg as water rushes out of the grouphead under pressure.
Repeat this process 2-3 times until you notice a foamy solution being emitted from the drain valve, this means the backflushing powder has formed a cleaning solution from the portafilter right through to the drain valve. Activate and deactivate the pump once more.
At this point the cleaning solution is dissolving build up coffee residue inside the brewing group, leave the machine to sit for 5 minutes or so. You may want to allow it to work longer if the machine has not been backflushed for some time.
Flushing the group
After the cleaning solution has been allowed to work, we need to flush it from the group head. Repeat the process as above by operating the pump until the pressure builds, allow it to operate for 1-2 seconds, the deactivate the pump. Repeat this process until the ejection from the drain valve starts to clarify to water only (no foam).
When there is minimal foam being emitted from the drain valve, the cleaning solution has been exhaused.
Rinsing the group
Now that the grouphead is clean we need to remove any traces of the cleaning product from inside the machine. Remove the portafilter and rinse any remaining cleaning product using the flow of water from the grouphead. Again, secure the portafilter into the brewing group and repeat the process of activating/deactivating the pump to force fresh water through the infusion and drain valves.
Repeat this process 3-5 times until nothing by water is emitted from the drain valve. Voila, you e61 grouphead is clean and ready for use.