Channelling

Category: infrastructure

An extraction defect where water finds paths of least resistance through an espresso puck rather than flowing uniformly.

Channelling occurs during high-pressure extraction if the dry coffee bed features uneven density, micro-fractures, or poor distribution. The pressurized water rushes through these narrow channels, resulting in localized over-extraction (causing bitter, astringent notes) while leaving the rest of the coffee bed under-extracted (sour, thin). It destroys extraction yield metrics and ruins consistency.

Common Examples

• Switching to a precision distribution tool eliminated espresso channelling, stabilizing our shot extraction times across the morning rush.
• Our point-of-sale telemetry flagged a sudden variance in shot times, indicating widespread extraction channelling caused by improper tamping technique.