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Dispersion block (diffuser)
The metal plate above the shower screen that spreads water from the group inlet evenly across the coffee puck.
Category: Espresso Machine — Groups & Brew Path
A thick metal plate (sometimes also called a diffuser) that sits above the shower screen inside the group head. Distributes water across the full diameter of the puck before it passes through the shower screen.
Why it matters — Without the dispersion block, water from the supply line would hit the centre of the basket hard, causing immediate channelling. The block spreads the flow evenly so water reaches the puck across its whole surface.
Good to know
- Dispersion blocks scale up over time, especially in hard water. Periodic removal and descaling restores even flow distribution.
- Some commercial groups use a separate dispersion plate plus the screen; the E61 design uses a single combined block.