Espresso Machine Cleaning Steps: How Long Should Backflushing Take?

Baristas must have encountered this problem: you've adjusted the espresso extraction parameters in the morning, but by noon, those parameters are no longer accurate, and the coffee flow rate has significantly slowed down.

FrontStreet Coffee has previously provided explanations for two situations regarding this issue. The first is during rainy days when the air humidity is high, the coffee beans in the bean hopper are easily affected by moisture. During grinding, they are also susceptible to interference from water vapor, causing the coffee grounds to clump and lose flavor, while also creating unstable extraction conditions.

The second situation is when the parameters are adjusted with the original coffee beans in the morning, but new coffee beans are added to the hopper in the afternoon, which requires readjusting the extraction parameters.

However, if neither of the above situations occurs, there might be another reason—the espresso machine is too dirty internally.

When extracting coffee, a small amount of coffee grounds gets sucked back into the group head. With long-term daily coffee extraction, many coffee residues accumulate inside the group head. This can obstruct the water outlet of the group head, making the coffee flow slower and unstable. Moreover, accumulated coffee residues can also affect water quality, causing undesirable flavors in the coffee.

Therefore, before turning off the coffee machine each time, it's necessary to clean the inside of the group head. This is done using a method called "backflushing." First, we use a blind filter, which is a portafilter basket without filter holes. This way, the water released from the group head has nowhere to go and must return to the pipes inside the group head to wash away the coffee residues remaining there.

The specific operation is to attach the blind filter to the portafilter handle, just like extracting coffee, and lock the portafilter onto the group head.

Then press the extraction button for 10 seconds, and the pressure relief outlet will discharge wastewater containing coffee residues.

When you remove the portafilter, there will also be a small amount of wastewater with coffee residues in the blind filter.

What we need to do next is to empty the wastewater from the blind filter, reattach it to the group head, and continue repeating the previous steps until the water in the blind filter is clear. Generally, repeating this 5 times will achieve this effect.

Some barista friends might say, "I already perform backflush cleaning when closing every day, why do I still experience unstable extraction parameters?" This is because it's not thoroughly cleaned. Some coffee residues are more stubborn and difficult to remove with ordinary water backflushing, which requires coffee machine cleaning powder to solve the problem.

The method is to first pour 2-3g of cleaning powder into the blind filter, then attach it to the group head, press the extraction button, and stop extraction after 5-7 seconds. At this point, the pressure relief outlet will spray white wastewater containing coffee residues.

Remove the portafilter, and the blind filter will contain water-soaked cleaning powder and coffee residues. At this time, you need to tilt it gently, pour out the water and residues from the blind filter, keep the water-soaked cleaning powder, continue attaching it to the group head, press the extraction button for 5-7 seconds, then remove the portafilter and empty the water from the blind filter, then reattach it to the group head, until the cleaning powder in the blind filter disappears when you remove the portafilter. Generally, repeating this 4-5 times will suffice.

Next, flush the group head water without a portafilter and gently brush the shower screen and gasket. After cleaning the blind filter, continue attaching it to the group head and repeat the water backflushing steps, but this time the purpose is to ensure that all cleaning powder inside the group head is discharged. Generally, repeat this about 7-10 times.

The frequency of cleaning with cleaning powder doesn't need to be too frequent. Typically, perform water backflushing daily and cleaning powder backflushing weekly.