1. Overview & Physics
Water Dispersion Mechanics
Espresso group heads dispense water via specific water paths, which can create localized impact points on the coffee bed. Placing a 150-micron mesh puck screen on top of the coffee puck diffuses the water streams, creating a gentle, uniform water blanket. This prevents top-puck erosion and channeling.
Clean Maintenance
Puck screens keep the group head clean by blocking coffee oils from backing up. Rinse the screen under the group head flush after every shot.
2. Practical Calibrations
Managing this requires measuring indicators in real time. Adjust grind size, water dynamics, and flow parameters incrementally. Change only one variable at a time to ensure clean results and isolate target parameters.
Barista Action Checklist
- Weigh dry grounds dry dose exactly to 0.1g.
- Calibrate water temperature using PID sensors.
- Target correct brew ratios (e.g. 1:15 for filter, 1:2 for espresso).
- Swirl or stir to ensure even saturation during extraction.
- Record extraction time and evaluate flavor notes subjectively.
Frequently Asked Questions
What is a puck screen?
A puck screen is a thin, reusable mesh disc placed on top of the tamped coffee puck to distribute water flow evenly.
Do puck screens prevent channeling?
Yes. They block high-velocity water streams from the group head from hitting the puck directly, creating a uniform shower effect.
