Group Head

The brass assembly on the front of an espresso machine where the portafilter locks in and brewing happens. The group transfers heat from the boiler to the puck and forms the pressure seal via the group gasket.

Why it matters — Group design fundamentally shapes how an espresso machine behaves. The most influential design in modern espresso is the E61 (Faema, 1961) — a thermosiphon-fed group used by Rocket, ECM, Profitec, Bezzera, Lelit, and many more. Saturated groups (La Marzocco, Synesso) connect the group directly to the brew boiler for maximum thermal stability.

Good to know

• E61 groups are heavy brass (2–4 kg) and stay hot via convection — that mass is why E61 machines often take 25–30 minutes to fully heat.
• Saturated groups warm up faster and hold temperature more stably than E61 groups, which is why most commercial machines use them.