51 vs. 54 vs. 58 mm Espresso Accessories: Stop Buying the Wrong Size
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Before you buy any espresso accessory, find the full model number on your machine, then match the size: the millimeter number is the basket diameter, and fit can still depend on basket depth, tabs and machine generation. The full version is the accessory size section of the Home espresso setup guide; the short version is here.
The four sizes
- 51 mm: compact consumer machines, including the CASABREWS CM5418 and the De'Longhi Dedica line. Most kits are 54 or 58 mm and most "universal" tampers are 58 mm, so search by the model name CM5418.
- 54 mm: most Breville and Sage home machines, including the Bambino and the Barista Express. Buy parts sold for Breville 54 mm; a 58 mm tamper will not seat.
- 57 mm: Lelit's own group on the Anna PL41; 58 mm parts do not fit.
- 58 mm: most prosumer and commercial-style groups, and the most stocked tamper size. Some baskets are 58.5 mm.
Not sure which size yours is? The Portafilter Size Finder lists it by brand and model, with what to buy and skip; in the guide it sits under Already have a machine in mind?
Check before you buy
Shop by exact model first and size second. A listing that says "universal" but does not name your machine is missing information, not reassurance. Before checkout, confirm the full model number (same-brand machines differ by generation), the exact part, and that the accessory maker names your model.
Which parts are risky to guess
Lowest risk to highest:
- Tamper: a poor match leaves an untamped ring.
- Dosing funnel: must match the diameter and the mounting.
- Puck screen: needs headspace in the basket.
- Replacement basket: depth and ridges matter.
- Full portafilter: locking tabs and group fit must match too.
Still choosing the machine?
Then pick the accessory size on purpose; neither machine below needs a grinder on day one.
Breville Bambino, 54 mm. Parts sold for Breville 54 mm fit it; pressurized and non-pressurized baskets are in the box. The catch: no built-in grinder, and 58 mm tools you own will not carry over. Our note
CASABREWS CM5418, 51 mm. A one-cup and a two-cup pressurized basket come in the box, so pre-ground espresso works from day one. The catch: 51 mm is the odd size, so every accessory is a search by model name. Our note
Adding a grinder? The Baratza Encore ESP has a 54 mm dosing cup and a 58 mm adapter in the box; a 51 mm machine works with the cup held under the chute.
The rest of the setup is in the Home espresso setup guide.