A handheld tool for compacting (“tamping”) ground coffee for espressoA small coffee beverage, about 20 ml, prepared on an espresso machine where pressurized hot water extracted through compressed coffee.: In its most stripped-down, basic form, this is... into a portafilterThe part of an espresso machine which holds the filter basket, into which coffee grounds are placed.: The part of an espresso machine which holds the filter basket,... basket. Tampers should match the size of a machine’s basket, with common sizes including 53mm and 58mm.