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Espresso gear  ·  CASABREWS 5418

What portafilter size does the CASABREWS 5418 use?

Explained
The short answerThe CASABREWS 5418 (model CM5418) uses a 51mm portafilter, not the 54mm size Breville uses or the 58mm commercial standard. Every basket, tamper, puck screen and bottomless portafilter you buy for it needs to be 51mm, and ideally listed as compatible with the CM5418 specifically.

The details

This answer covers the CASABREWS CM5418 and the 5418 Pro, which share the same 51mm portafilter platform with the CASABREWS 3700 series (3700Essential, 3700Gense, 3700Pro).

  • The stock portafilter is 51mm with a three-ear (three-lug) mount and ships with pressurized (dual-wall) baskets.
  • CASABREWS sells its own 51mm bottomless portafilter and 51mm accessories listed as fitting the CM5418, 5418 Pro and 3700 series. These are the safest buys.
  • Third-party 51mm bottomless portafilters that name the CM5418 in the listing are widely used by owners.
  • 51mm is a common small-machine size, but it is not one single standard: basket depth, ear spacing and gasket dimensions vary between brands. A 51mm part made for a De'Longhi or another brand is not guaranteed to lock into the CASABREWS group.

Why the size matters

Portafilter size decides your entire accessory ecosystem. At 51mm the CASABREWS sits in the compact class, which means a smaller basket bed than 54mm or 58mm machines and a dose ceiling to match. Owners moving from recipes written for bigger machines should expect to dose less than those recipes state and dial in from there rather than forcing a large dose into the small basket.

The stock pressurized baskets are forgiving with supermarket grinds but hide puck problems. The common upgrade path is a 51mm unpressurized basket or a CM5418-compatible bottomless portafilter, which only makes sense once you have a grinder capable of espresso-fine adjustment.

What owners actually do

The typical CM5418 upgrade sequence in owner communities: first a proper 51mm tamper to replace the plastic stock one, then a 51mm puck screen, then the bottomless portafilter with an unpressurized basket once a real grinder arrives. CASABREWS' own bottomless kit ships with a basket and puck screen sized for the machine, which sidesteps the mix-and-match fit questions entirely. Owners who buy generic 51mm parts report checking two things before purchase: that the listing names the CM5418 or 3700 series, and that the basket depth matches their target dose.

The trap to avoid

The trap is assuming "51mm" means universal. It does not. The ear pattern that locks the portafilter into the group head is brand-specific, so a 51mm portafilter made for another manufacturer can fail to rotate into the CASABREWS group even though the baskets share a diameter. Baskets are more interchangeable than portafilters, but depth still varies. When in doubt, buy parts that name your exact model, and keep the stock portafilter as a fallback.

People also ask

Do 54mm Breville accessories fit the CASABREWS 5418?

No. The CM5418 is 51mm, so 54mm tampers, baskets and screens made for Breville machines are too large. Buy 51mm parts listed for the CM5418.

Is there a bottomless portafilter for the CASABREWS 5418?

Yes. CASABREWS sells a 51mm bottomless portafilter listed for the CM5418, 5418 Pro and 3700 series, and several third-party 51mm bottomless portafilters name the CM5418 as compatible.

Can I use unpressurized baskets in the CM5418?

Yes, 51mm unpressurized baskets work, but they demand an espresso-capable grinder. The stock pressurized baskets exist to compensate for coarse or inconsistent grinds.

Will a generic 51mm portafilter from another brand lock in?

Not reliably. The 51mm diameter is shared but the ear pattern that locks into the group is brand-specific. Choose portafilters whose listings name the CASABREWS CM5418.

Last checked 2026-07-29. Spotted something out of date? The specs change; the answer gets rechecked.