Accessories
Choosing a Tamper: Size and Fit Explained
A tamper is a simple tool, but getting the size wrong makes an even tamp much harder than it needs to be, no matter how good your technique is.
Match the tamper to your basket diameter
A tamper base should closely match your portafilter basket's inner diameter (51mm, 54mm, or 58mm are common); a tamper that is too small tends to compress unevenly toward the basket walls, leaving an untamped ring around the edge that is a direct channeling risk.
Flat vs convex base
A flat base is the most common and straightforward choice; a slightly convex base is preferred by some baristas, though the difference matters far less than a properly sized, level tamp — this is a preference choice, not a performance one.
What does not matter much
Handle material and tamper weight are largely personal preference and have little documented effect on shot quality compared to matching the base size correctly — do not let a premium-looking handle distract from checking the base diameter matches your basket.
How to check your basket size before buying
Your portafilter's basket size usually matches the portafilter size documented for your machine (see our portafilter size guide) — check your machine's specification table rather than measuring by eye, since a millimeter or two of mismatch is enough to cause an uneven tamp at the basket wall.
Calibrated vs standard tampers
A "calibrated" tamper stops at a fixed depth inside the basket regardless of how hard you press, aiming to remove tamp-pressure variance entirely. This solves a real problem for some users, though it is a smaller factor than getting the base diameter right in the first place — a calibrated tamper in the wrong size still tamps unevenly.
A tamper is not a substitute for good distribution
No tamper, however well-fitted, corrects for unevenly distributed grounds underneath it — see our tamping guide for why leveling the dose before tamping matters more than the tamp itself. A great tamper used on a poorly distributed puck still risks an uneven result.