Breville Portafilter: 54mm Sizing and Bottomless Options
Breville home machines are 54mm, not 58mm. The genuine part is SP0027237; compatible 54mm portafilters and bottomless versions both fit the same group.
Also sold as: Compatible 54mm portafilters; Normcore and similar bottomless versions
Does it fit your machine?
Match your model number exactly — the code on the rating label, not the name on the front of the machine.
| Model | Notes |
|---|---|
| Barista Express (BES870XL) | 54mm |
| Barista Pro | 54mm |
| Bambino / Bambino Plus | 54mm |
| Infuser | 54mm |
| Dual Boiler (BES920) | 58mm - different size, check before ordering |
Your model is not on this list. Do not assume it fits — send us the model number and we will check it.
OEM or aftermarket?

The direct replacement:
Prime Breville 54mm Portafilter SP0027237 – Genuine Replacement for Bambino BES450, Bambino Plus BES500, Duo-Temp Pro BES810, Infuser BES840, Barista Express BES870
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The single most useful fact about Breville portafilters: the home machines use 54mm, not the 58mm size used on most commercial and prosumer equipment. Barista Express, Barista Pro, Bambino, Infuser and the rest of the domestic line are all 54mm. Buying 58mm because that is what most espresso content assumes is the classic expensive mistake in this niche – a 58mm basket will not seat, and a 58mm portafilter will not lock into the group.
Genuine, compatible or bottomless
- Genuine Breville (SP0027237) – the direct replacement if yours is cracked, the handle has failed, or you want a second one so you can prep two shots. Expect to pay a premium for the part number.
- Compatible 54mm portafilters – noticeably cheaper and generally fine. Check the listing names your model, because spout geometry varies.
- Bottomless (naked) portafilters – no spouts, so you can watch extraction directly. This is a diagnostic tool as much as an upgrade.
What a bottomless actually tells you
With the base removed you see the puck as it extracts. Spraying and squirting from one side means channelling – uneven tamping, an uneven grind bed, or too little coffee. Even, slow, honey-coloured flow means the puck prep is right. That feedback is why a bottomless is worth buying even if you never leave it fitted, and it explains most “my espresso tastes sour” complaints faster than any amount of grinder adjustment.
The trade-off is that a bad shot goes over the drip tray and the counter rather than down two spouts. Expect mess while you learn.
Baskets are a separate decision
The portafilter is the handle and body; the basket is the perforated cup inside it. Single, double and precision baskets all fit the same 54mm portafilter, and swapping to a precision basket is usually a bigger improvement in the cup than changing the portafilter itself. Do not assume a new portafilter arrives with the basket you want.
Fitting and care
Wipe the group gasket before locking in – grounds on the gasket are the usual cause of a portafilter that will not seat squarely or that drips at the edge. If yours has started leaking around the rim on a machine that used to seal fine, the group gasket is a more likely culprit than the portafilter.
54mm and 58mm: why the confusion costs money
Almost every espresso tutorial, accessory review and grinder guide online is written around 58mm, because that is the commercial standard and what most prosumer machines use. Breville’s domestic range is 54mm, and the two are not close enough to force. A 58mm basket will not drop into a 54mm portafilter, and a 58mm tamper sits proud on a 54mm bed and compresses the middle while leaving the edges loose.
Before ordering anything that touches the puck — portafilter, basket, tamper, distribution tool, puck screen — check the number, not the brand. The exception in Breville’s own line is the Dual Boiler, which is 58mm. It is the one model where the general espresso advice applies directly.
What a bottomless portafilter shows you
Removing the spouts turns the portafilter into a diagnostic window. You watch the underside of the basket as the shot runs, and the pattern tells you what the puck is doing:
- Even, slow, honey-coloured flow that converges into one stream — the puck is prepped correctly.
- A jet spraying sideways from one point — channelling. Water has found a low-resistance path, usually from an uneven grind bed or a tamp that was not level.
- Blonde, fast flow almost immediately — the grind is too coarse or the dose too low for the basket.
- Nothing for ten seconds, then a burst — too fine, or tamped hard enough to compact the bed unevenly.
None of that is visible through spouts. If your shots are inconsistent and you cannot work out why, a bottomless is a faster diagnosis than any amount of adjusting one variable at a time.
Baskets matter more than the handle
The portafilter is a holder; the basket does the work. A worn or cheap basket has unevenly punched holes, and uneven holes cause uneven extraction no matter how good your technique is. Precision baskets are laser-drilled to a consistent pattern and cost far less than a new portafilter.
Basket sizes are specified by dose: an 18g basket wants about 18g of coffee. Putting 14g in an 18g basket leaves headroom above the puck, water pools there and channels around the edges, and the shot gushes. That single mismatch causes more “my machine will not build pressure” complaints than any hardware fault.
Care, and the gasket that fails first
Wipe the group gasket before every lock-in. Grounds on the gasket stop the portafilter seating square, which shows up as a drip from the rim during the shot and, over months, as a gasket that has hardened into a permanently compressed ring.
Backflush weekly with a blind basket and detergent if your machine supports it. Rinse the portafilter and basket in hot water after each session rather than leaving oils to polymerise — dried coffee oil is what turns a bright shot dull, and no amount of grind adjustment brings it back.
A hardened group gasket is a cheap part and a common cause of what looks like a pressure fault. If your portafilter has started leaking at the rim on a machine that used to seal fine, replace the gasket before you suspect the pump.

Related on BrewerRepair: Breville Water Filter (BWF100) and Breville Espresso Machine Not Building Pressure and Descaling a Breville Barista Express.
54mm portafilters that fit
All 54mm. The genuine SP0027237 is the direct replacement; the bottomless is the diagnostic tool.
Where to buy it

Breville
Breville Portafilter: 54mm Sizing and Bottomless Options
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Questions about this part
Is a Breville portafilter 54mm or 58mm?
Domestic Breville machines including the Barista Express are 54mm. The Dual Boiler is 58mm. Check before ordering.
What is the genuine Breville portafilter part number?
SP0027237 for the 54mm portafilter.
Is a bottomless portafilter worth it?
As a diagnostic tool, yes. It shows channelling directly, which is faster than guessing at grind and tamp.
Does a new portafilter come with a basket?
Not always. Baskets are sold separately and a precision basket often improves the cup more than the portafilter does.
Repairs that need this part
Breville Not Building Pressure: Puck First, Machine Second
A Breville that gushes and never reaches pressure is usually a grind and dose problem, not a pump fault. How to separate the two definitively.