Gicleur

A small brass jet (typically 0.6–0.8 mm) that meters water flow into the group — limits pressure ramp and brew flow.

Category: Espresso Machine — Groups & Brew Path

A small jet (a brass or stainless piece with a precise hole drilled through it) located inside the E61 brew valve. Restricts water flow into the group, creating a natural pre-infusion before pressure builds.

Why it matters — Gicleur size is the single biggest variable in how an E61 group behaves during the early shot. Smaller gicleurs (0.6 mm) extend pre-infusion and produce gentler ramps; larger gicleurs (0.9 mm+) snap the shot faster.

Good to know

Standard E61 gicleurs are 0.8 mm. Many users dial down to 0.6 mm for light roasts and very fresh coffee.
Swapping gicleurs takes 5 minutes with a hex key — keep a couple of sizes on hand and experiment.