A portafilter is the handled device into which ground espresso is tamped and then locked into the group head of an espresso machine for brewing. The diameter of this device’s basket, where the coffee grounds reside, is a crucial element affecting espresso extraction. Breville, a prominent manufacturer of espresso machines, offers machines that typically use 54mm diameter portafilters, although 58mm portafilters can be found on some models. This dimension dictates the volume of coffee grounds used and influences the water flow rate during brewing.
Matching the correct basket size to the machine ensures optimal extraction. Using an incorrectly sized basket can lead to over-extraction (bitter, burnt taste) if too little coffee is used, or under-extraction (sour, weak taste) if the basket is overfilled. Historically, manufacturers have varied in their chosen portafilter sizes, but standardization around 54mm and 58mm has become common, particularly for prosumer and consumer models. The correct fit is essential for achieving the intended pressure and water distribution through the coffee puck. This precise interaction between water and coffee grounds determines the final espresso’s flavor profile, body, and crema.