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Gicleur (jet)
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
The flow-restricting jet inside the E61 brew valve — typically a precision-drilled brass or stainless component with a hole between 0.5 and 1.0 mm in diameter. Controls how aggressively water reaches the puck during pre-infusion.
Why it matters — The gicleur is the hidden tuning variable in every E61 machine. Smaller hole = slower water = gentler shot; larger hole = faster water = snappier shot. Two identical machines can taste different just because of gicleur size.
Good to know
- Standard size is usually 0.8 mm. Lighter roasts often benefit from 0.6 mm; older traditional-roast workflows use 0.8–0.9 mm.
- Don't go below 0.5 mm — flow restriction at that size starts affecting full-pressure extraction, not just pre-infusion.