Every bean-to-cup machine has a brew unit: the mechanism that receives the ground coffee, compresses it, passes water through, and ejects the puck. It is the busiest part of the machine and the one that accumulates oil.
Removable
De’Longhi, Philips, Melitta and most of the mass market. Two tabs, pull, rinse under a tap, push back — ten seconds, once a week.
The benefit is not only cleanliness but inspectability. When a machine starts behaving oddly, you can look at the part that does the work. Nine times out of ten the answer is visible.
Sealed
JURA, Siemens, Miele, most premium brands. The unit is inside and cannot be reached. Cleaning happens by pushing a tablet through the machine on a cycle.
That works, and it works well for years. What it cannot do is let you see anything, and when the unit eventually needs attention the machine goes to a workshop — a bill that is a meaningful fraction of the machine’s value.
Why the premium brands do it
Not laziness. A sealed unit can be more tightly engineered, better sealed against pressure, and integrated more closely with the rest of the hydraulics, which contributes to the better extraction those machines genuinely achieve. It is a real engineering trade, not a cost-saving.
How to choose
If your priority is the cup and you accept a possible workshop bill in year seven, a sealed unit is a defensible choice and those machines do make better espresso.
If your priority is owning a machine for a decade and fixing it yourself, buy a removable unit and accept slightly less good coffee. That is the trade, stated plainly.
Questions people actually ask
How often should I rinse a removable brew unit?
Weekly under a warm tap, no detergent, and let it dry before refitting. Monthly, add a proper brew-unit cleaning tablet.
Do cleaning tablets really work on sealed units?
Yes, and for a long time. They are a genuine detergent cycle rather than a token gesture. What they cannot do is remove a mechanical fault or let you verify the result.
Last reviewed 8 August 2026