When purchasing a semi-automatic or manual espresso machine another very important thing to consider acquiring is a tamper. A tamper is the critical tool for leveling and compacting ground coffee in a portafilter to make espresso. Some espresso machine manufacturers include a tamper with the machine, but many do not. Espresso coffee tampers come in a variety of materials among them stainless steel, aluminum, chrome plated steel, and plastic.
Solid plastic tampers will eventually curl up around their edges and not seal properly when tamping giving you an undesirable poor quality shot of espresso. They should be replaced with either an aluminum or stainless steel tamper.