How often does the shower screen of your espresso machine needs a shower?
The water you use to brew espresso will pass through the shower screen just before it came into contact with the coffee ground. Imagine your shower screen that is dirty and lined with rancid oil and coffee stains from months ago. It is no surprise your coffee leave a bad taste in your mouth.
But most of the time when you look at the screen from below, the screen looks very clean and shiny. That’s because the outside is fairly easy to clean. Just using hot water and a heat-resistant brush will make the external looks good.
It has been a standard practice for a properly trained barista to clean the grouphead everyday with espresso machine grouphead cleaning detergent. And if they do a thorough cleaning everyday that include back-flushing the grouphead with detergent, the grouphead including the shower screen will be up to standard for months. But some may asked, do we need to totally remove the shower screen to clean the inside of the screen?
Here are a few examples of the shower screen used for 4 months.
In Figure #1: This is a shower screen on a machine where the grouphead was not cleaned nor back-flushed with detergent. They did clean them with a brush and hot water but did not use the appropriate detergent. While from the outside, it looked clean and shiny, the underside (or inside) of the shower screen is very dirty, stained with thick rancid oil and clogged with fines from the coffee ground. Every time when espresso is extracted, the water have to pass through the fines and rancid oil before coming in contact with the fresh coffee ground. The resulting espresso is a mixed of fresh coffee flavor [assuming you are using fresh roasted coffee] and stale and rancid coffee oil accumulated over the months.
In Figure #2: This shower screen on the machine where the grouphead was cleaned and back-flushed everyday with detergent. Here, you can see a very slight stain of light brown but not visible clogging of the shower screen by fines. The impact of bad flavor cross contaminate from stale and rancid oil to your fresh coffee ground will be minimal.
In Figure #3: This is a shower screen that has been properly cleansed.
What would KF Chan recommend? Do you need to remove and clean the shower screen every day? I would say it is not necessary to remove the shower screen for cleaning every day. I would recommend to remove the shower screen every 3-4 months, with the maximum of 6 months interval if you are lazy.
**Do note that frequent removal of the shower screen will speed up the wear and tear to the grouphead gasket. A good quality grouphead gasket cost around RM80-RM100 [USD20] and usually can last for a year. You do not want to wear out the gasket earlier than necessary.