Welcome back to The Technician’s Dispatch, a series of articles about home espresso machine care and maintenance, written and compiled by the La Marzocco Home team. This series focuses on providing home espresso machine owners and aspiring home baristas with the knowledge and skills they need to maintain their La Marzocco and produce the highest quality espresso imaginable. From preventive maintenance tips to troubleshooting guides and step-by-step repairs, The Technician’s Dispatch is your go-to resource for resolving common espresso machine issues and optimizing performance.
The Tales of the Dirty Solenoid
Backflush from the Living Dead…
by Kimberly Franklin, La Marzocco Home Solutions
You thought it was just another morning espresso…
You thought the machine was fine…
But deep inside the pipes, something foul was brewing.
Coffee oils. Old. Rancid. Forgotten.
And then a click. A Hiss. A Groan.
From the heart of the machine came a sound that chills a barista’s blood
“You never backflushed me…”
That’s when you realize: your machine’s solenoid has awakened… as a zombie.
Monster in the Machine
What is A Solenoid Valve?
Much like the vacuum breaker in The Mystery of the Hissing Vacuum Breaker, the solenoid valve is often overlooked, until its failure makes itself known in an unnerving way.
Every espresso machine hides a little gatekeeper called the solenoid valve. It’s a small but mighty electrically-controlled valve that decides when pressurized water flows through the group head. Start your espresso shot, it opens. Stop the shot, it snaps shut.
When it’s clean, it’s precise and obedient. But neglect it, and those coffee oils stick like zombie goo. The solenoid gums up, valves jam, and suddenly your machine starts acting possessed: Dripping when it shouldn’t… pulling shots that taste like… the undead. And like a zombie bite, it will spread into the rest of the machine unless you fight back.
Backflushing vs. Descaling: Know Your Weapons
The only way to hold the solenoid gates and keep the espresso dead from rising? Backflushing. We recommend doing it daily, or you could risk the grind-soaked apocalypse no barista wants to face.
A common misconception is that backflushing (i.e. using Puro Cafe) the machine is the same thing as descaling the machine. These are two completely different things.
Descaling — The ritual of dissolving mineral buildup(often called scale) in boilers and water pathways. Necessary if your water is “hard,” but it won’t clean the solenoid of oily residue as backflushing will.
Descale = Dissolving mineral build up(scale) inside the machine.
Backflushing — The exorcism for the solenoid. By forcing water and the detergent solution backward through the group head, you flush out the oils that would otherwise clog up the solenoid valve.
Backflush = Dissolving coffee oils inside the group head of the machine.
It’s important to note that if you’re using proper water and using the machine, on a regular basis, then there should be no need to descale a La Marzocco machine. We go over this and other best practices in our blog post: Tech Tips for Home Espresso Machines
Backflush Survival Plan
Gear: La Marzocco Cleaning Basket. Puro Caff Espresso Machine Cleaner. Towel.
Schedule
Daily: Water-only backflush.
Weekly: Detergent backflush, soak metal parts in cleaner.
Monthly: Remove screen and soak in cleaner, deep clean, check the gasket.
How-to
Water-only: lock in blind basket, run 8–10 seconds, stop 8–10 seconds, repeat 5–7 times, rinse.
With detergent: ¼ tsp cleaner in blind basket, run 8–10 seconds on and off 8–10 times, rinse until no suds, soak baskets and metal parts, rinse well.
How to clean Linea Micra Video
How to clean Linea Mini Video
How to clean the GS3 AV Video
Notes
Clean sooner if you notice:
– Sputtering at the group when unlocking the portafilter after pulling an espresso.
– Persistent “coffee smell” from the group even after rinsing.
– Greasy residue on the shower screen.
The End?
So, next time you hear a groan from your espresso machine, ask yourself: Did you backflush today? Or is your solenoid already clawing its way out of the grave, ready to curse every cup with the bitter taste of the Espresso Dead? Because once the solenoid goes rotten… no cricket bat can save your morning.
Stay safe, stay caffeinated, and keep those solenoids alive and clean.
