Guide · Tamping
58 mm, 58.4 mm or 58.5 mm tamper?
Most 58 mm basket makers we checked specify a 58.4 mm tamper, one accessory maker lists 58.5 mm and Decent advises against it. How to pick for your basket.
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Short answer
Use the size your basket's maker specifies. For the 58 mm baskets we could check, that is 58.4 mm: VST, IMS, Flair and Profitec's own manual all name it.[1][2][3][4] Normcore's compatibility guide lists 58.5 mm for many of the same machines, while Decent uses 58.35 mm and advises against 58.5 mm.[5][6] If you cannot identify your basket, 58.35 to 58.4 mm is the range most of these sources agree on.
What each source says
| Source | Kind | Tamper size it gives | Notes |
|---|---|---|---|
| VST precision baskets (15 to 25 g) | Basket maker | 58.40 mm (+0.00 / −0.05 mm)[1] | A flat tamper; anything larger is outside VST's tolerance |
| IMS B70 and competition baskets | Basket maker | 58 / 58.4 mm[2][7] | The same figure appears on IMS's single basket[8] |
| Flair 58, standard basket | Machine maker | 58.4 mm best; 58.5 mm the largest it recommends[3] | The basket tapers from 58.7 mm at the top to 58.5 mm |
| Profitec PRO 400 & JUMP manual | Machine maker | 58.4 mm[4] | Profitec's own walnut tamper is 58.5 mm and marketed for the JUMP[9] |
| Decent Espresso | Tamper maker | 58.35 mm; does not recommend 58.5 mm[6] | Says a very close fit can lift the puck |
| Normcore | Accessory maker | 58.5 mm for the 58 mm machines in its guide[5] | A recommendation for its own tampers and screens |
| Rocket and Gaggia | Machine makers | 58 mm, their own tampers[10][11] | The nominal size of the group |
Normcore's 58.5 mm list is long: it covers the Gaggia Classic, Rancilio Silvia, Flair 58, Breville Dual Boiler and Oracle, and 58 mm models from Profitec, ECM, Rocket, Lelit and Ascaso.[5] So this is not a fringe figure. It is simply a different answer from the one basket makers give.
Why the sources disagree
A tamper is a trade-off between gap and clearance. The tamper has to slide into the basket, and the space between its base and the wall is a ring of coffee that never gets pressed. A larger base shrinks that ring but leaves less room to move. Decent's argument against 58.5 mm is the other side of the trade: a very close fit can lift the puck as you raise the tamper.[6]
Baskets are not straight tubes. Flair's standard basket is 58.7 mm across at the top and narrows to 58.5 mm, so a 58.5 mm base only just fits where it narrows.[3] That is why Flair calls 58.4 mm the best fit and 58.5 mm the maximum.
"58 mm" is a name, not a measurement. Gaggia's own accessory pages give its wooden-handle filter holder a 58 mm filter diameter, its bottomless filter holder 59 mm, and the IMS filter bundled with it 70 mm.[12][13] The 70 mm figure is most likely the basket's rim, since IMS lists a 70 mm border on its B70 baskets, but that is our reading; Gaggia does not say.[2] None of these labels is the diameter a tamper needs.
Makers are not always consistent with themselves. Profitec's PRO 400 & JUMP manual recommends a 58.4 mm tamper, yet its 58.5 mm walnut tamper is marketed for the JUMP.[4][9] Normcore's figure, for its part, is an accessory maker's recommendation for its own products rather than a basket specification.
How to choose your size
- Find the basket's maker. Many baskets are stamped with a brand or code. For a VST basket, use 58.40 mm. For an IMS basket, use the figure on its product page: 58/58.4 mm for the B70 family.[1][2]
- Using a Flair 58 with its standard basket, or a Profitec PRO 400 or JUMP? Follow the maker: 58.4 mm.[3][4]
- Basket unknown? Measure its inside diameter with calipers at the depth where the coffee bed sits, not across the rim. The basket size guide shows how.
- Choose 58.5 mm only when your basket allows it: when its maker accepts 58.5 mm, as Flair does,[3] or when your measurement leaves clearance. If you follow Normcore's 58.5 mm figure,[5] check that the tamper does not scrape the wall or pull the puck up as you lift it.
- A plain 58 mm tamper will fit, as the tampers Rocket and Gaggia sell for their own machines show, but it leaves a wider untamped edge than 58.4 mm.[10][11]
In-between sizes exist if you want to split the difference: MHW-3BOMBER's own store lists a 58.35 mm impact tamper, and Normcore's V4 comes in both 58 and 58.5 mm.[14][15]
The same question for puck screens
A puck screen sits on top of the tamped coffee, so it has to drop into the basket and lie flat. Normcore lists 58.5 mm screens for the same machines it lists 58.5 mm tampers for.[5] Whatever the label says, a screen should go in and come out without force. Our guide to whether puck screens are worth it covers sizing and headspace.
Machines with sourced 58 mm sizes
Breville's Dual Boiler and Oracle Touch use a 58 mm portafilter, and IMS serves them with its B70 baskets.[16][17][18] The Rancilio Silvia and Silvia Pro X use 58 mm portafilters, and Gaggia gives the Classic E24 a 58 mm filter holder.[19][20][21] The Profitec PRO 400 and Flair 58 have the explicit 58.4 mm guidance above. Each machine page lists its own sources.
Next
Questions
Is a 58.5 mm tamper better than a 58 mm one?
Not automatically. A closer fit leaves a thinner untamped edge, but VST, IMS, Flair and Profitec's PRO 400 manual all specify 58.4 mm, and Decent advises against 58.5 mm because a very close fit can lift the puck.[1][2][3][4][6]
Will a 58 mm tamper work in a 58 mm portafilter?
Yes. It is smaller than the 58.4 mm that basket makers specify, so it fits, and Rocket and Gaggia sell 58 mm tampers for their own machines. The trade-off is a slightly wider ring of untamped coffee at the edge.[10][11][1]
What size tamper fits a Breville Dual Boiler?
Its portafilter is 58 mm, and IMS serves it with B70 baskets that list a 58/58.4 mm tamper. Normcore lists 58.5 mm for it. Go by the basket you actually use.[16][18][2][5]
Why does Profitec list two different tamper sizes?
Its PRO 400 & JUMP manual recommends a 58.4 mm tamper, but its 58.5 mm walnut tamper is marketed for the JUMP among other machines. We report both; for those two machines the manual is the more specific document.[4][9]
Does the same rule apply to puck screens?
Mostly. A screen sits on the tamped puck and must drop in and lift out without binding. Normcore lists 58.5 mm screens for most 58 mm machines, so check that yours lies flat in your basket.[5]