Portafilter

A portafilter is a key component of an espresso machine that holds the ground coffee during brewing. It consists of a handle attached to a metal basket and is locked into the machine’s group head to create a seal under pressure, allowing hot water to pass through the coffee for extraction.

Most portafilters use a standard 58-millimeter diameter basket, though sizes can vary by machine. The main parts are the handle, the filter basket, and, in some designs, one or two spouts for pouring. The basket is removable for dosing and cleaning. Materials commonly include stainless steel or brass for the body, with a plastic or wooden handle on some models.

Two main basket types are commonly encountered. Non-pressurized (single-wall) baskets require precise grind, dose, and tamping to control flow and extraction quality. Pressurized (double-wall) baskets use a secondary chamber to stabilize extraction, making it more forgiving for coarser grinds or beginner setups. Bottomless, or naked, portafilters have no bottom wall or spouts, allowing direct viewing of the extraction and puck behavior for diagnostics. Some portafilters also offer one or two spouts to direct espresso into cups.

Usage and maintenance: the portafilter is preheated, loaded with evenly dosed and tamped coffee, and locked into the group head before brewing. After use, the basket is removed and cleaned, and the portafilter is rinsed to prevent residue buildup. Regular cleaning and proper backflushing (where applicable) help prevent channeling and maintain consistent extraction. Compatibility is tied to group-head size, with 58 mm being the standard for many machines.