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Pre-infusion
Low-pressure phase at the start of a shot to wet the puck before full pressure.
Category: Extraction — Workflow & Technique
A low-pressure phase at the start of a shot, where water reaches the puck below full brew pressure. The puck wets, expands, and settles before the pump ramps to 9 bar.
Why it matters — Pre-infusion gives the puck time to saturate evenly, which reduces channelling and improves extraction uniformity. It's especially valuable for light roasts and fresh coffee.
Good to know
- Pre-infusion can be mechanical (E61 groups have a built-in expansion chamber that creates natural pre-infusion) or electronically programmed (Decent, Breville Dual Boiler, La Marzocco GS3).
- Typical pre-infusion duration: 5–10 seconds; longer (12–15 s) for very light roasts or very fresh coffee.