- Availability: Common
A tamper is a metal disc on a handle, sized to fit a 58 mm (or 53 mm) portafilter basket. Modern calibrated tampers limit the press to roughly 30 lb of force, which has been shown to be the threshold beyond which more pressure makes no difference. The skill is in the level: an angled tamp produces uneven extraction. Self-leveling tampers are increasingly common at high-volume Brooklyn bars to reduce wrist strain on baristas.