Gicleur sizing

Changing the size of the jet (gicleur) inside an E61 group head to alter how aggressively water reaches the puck during pre-infusion and the early shot. Common sizes are 0.6, 0.7, 0.8, and 0.9 mm.

Why it matters — A smaller gicleur slows pre-infusion and smooths water entry — better for light roasts and very fresh coffee. A larger gicleur snaps the shot faster — better for darker roasts and high-volume cafés.

Good to know

• Swapping gicleurs takes 5 minutes with a hex key.
• Don't go below 0.5 mm — at that size, flow restriction starts affecting full-pressure extraction, not just pre-infusion.