Fixing Spraying Espresso
Spraying or spurting shots indicate severe channeling. Here's how to fix them.
⚡ Quick Answer
Spraying or spurting espresso indicates severe channeling—water finding a path of least resistance through the puck and escaping at high velocity. This happens from uneven distribution, cracks in the puck, grinder clumping, or tamping issues. The shot will be unevenly extracted with both sour and bitter notes. Fix: Use WDT (Weiss Distribution Technique) to break clumps and even out grounds. Ensure level tamp—uneven tamping creates high and low spots. Check grinder for clumping issues; some grinders need RDT (water droplet) to reduce static. Reduce grinder retention which causes stale clumps. If using bottomless portafilter, watch where spray originates to identify the channel location. Spraying often indicates the worst channeling; minor channeling creates faster flow without visible spray.
🎯 Key Takeaway: Spraying = severe channeling. Use WDT for distribution, ensure level tamp, check for grinder clumping. Bottomless portafilter helps identify problem areas.
Causes of Spraying
1. Severe Channeling (Primary)
Water finds a crack or weak spot and jets through at high pressure, spraying out. Caused by uneven density throughout the puck.
2. Grinder Clumping
Clumps create hard spots that resist water, forcing flow around them in channels. Static makes clumping worse.
3. Uneven Tamp
Tilting the tamper creates high and low spots. Water flows through thin areas, bypassing thick areas.
4. Pre-Infusion Cracks
Aggressive pre-infusion can fracture the puck, creating persistent channels through the shot.
Solutions
- 1. Use WDT tool: Break up all clumps, ensure even distribution before tamping
- 2. Level tamp: Use a distribution tool or ensure flat tamp—no tilting
- 3. Check grinder: RDT (water droplet) to reduce static and clumping
- 4. Reduce retention: Single dose, purge grinder between shots
- 5. Adjust pre-infusion: If too aggressive, reduce pressure or duration
- 6. Bottomless portafilter: Visual feedback on channel location