What Is an Espresso Group Head?
You're staring at the front of your espresso machine. There's a handle locked into a round fitting, and something around it looks grubby or leaks. That fitting is the group head, and it's the part this site is about.
What the group head is
It's the receiver for the removable portafilter, which some people call the group handle1. The portafilter is the handle with the basket that holds your ground coffee. It's made up of a filter basket, a locking mechanism and a way to attach it, such as a handle1.
The group head is where the machine and the coffee meet. Hot, pressurised water comes out of the machine here, passes through the coffee and ends up in your cup.
Most home machines have just one. Wikipedia says a typical consumer machine normally has only one. Professional machines, such as those in coffee shops, can have one to seven1.
What you can see in there
Look up into the fitting with the portafilter out. You'll see a few things.
| What you see | What it does |
|---|---|
| The many small holes (the shower) | Spread the pressurised water evenly over the coffee in the basket1 |
| A ring around the rim | The gasket. The portafilter forms a seal with it1 |
The next page, Group Head Parts, names each piece in more detail and says what to look for.
Why a maker asks you to keep it clean
Think of a doorway that every cup of coffee has to pass through. One maker's manual puts it this way: the area where the portafilter locks into place gets exposed to a lot of coffee and must be kept clean2. It goes on to say that coffee residue left there can degrade performance over time2.
That same manual tells the owner to give the area where the gasket sits a good scrubbing with the brush supplied with the machine2. Check what came in your own box, as makers differ.
Where the brown film comes from is the topic of a later page on buildup.
Not every group head gets cleaned the same way
Some machines let you run a cleaning tablet through the group head with a special disc or blind basket. One maker's manual describes a cleaning cycle that cleans the shower screen and back-flushes the group head3. Other machines have a different design, and that same method could be wrong for them.
So the first job is simple. Find the cleaning section of your own manual and read it. If you've lost the booklet, look on the maker's own support page.
Two things to keep in mind:
- Cleaning means the parts you can reach from the front. Anything behind a panel is for the maker or a qualified technician.
- A method that suits one machine can harm another. Your manual decides, not a forum post and not this page.
Curious about backflushing, and whether your machine can do it? Read What Is Backflushing.
Where the facts come from
- Espresso machine, Wikipedia
- After each session, Backflushing, Vibiemme Domobar Junior User Manual, Vibiemme (manual page hosted by ManualsDir)
- Breville BES980 Manual, Care and Cleaning, Breville (manual page hosted by ManualsOnline)
More group head pages
Group Head Parts: Gasket, Shower Screen and Dispersion PlateRings, discs and a screw sit inside the group head. Here's what each is called, what it does and which jobs are for the owner.
Why Group Heads Get Dirty: Coffee Oils and Fine GroundsBrown buildup around the group head comes from coffee oils and grounds. Here's how it forms, what it looks like and what makers say to do.
What Is Backflushing and Which Machines Can Do It?Backflushing pushes water or cleaner back through the group head with a blind basket. Here's what it means and how to tell if your machine allows it.