Why Is My Moka Pot Not Percolating?
When a Moka pot produces no coffee or only a trickle, it's almost always a grind, seal, or safety valve issue. Each has a distinct diagnosis.
⚡ Quick Answer
Three most common causes: (1) grind too fine — clogs the filter and blocks water flow, (2) rubber gasket worn or not seated properly — pressure escapes instead of pushing water up, (3) safety valve blocked — pressure can't build correctly. Check all three before assuming the pot is broken. Also confirm: lid closed, water at correct level, and pot assembled in the correct order.
🎯 Diagnosis: Spitting/struggling = grind too fine. Steam escaping from sides = bad gasket. Safety valve activating = overfilled or clogged filter. No activity at all = incorrect assembly or heat problem.
⚙️ Cause-by-Cause Diagnosis
1. Grind too fine
Symptoms: coffee barely trickles out, sputters, or makes straining sounds. Filter basket may be clogged with compressed grounds.
Fix: Grind coarser — use medium-fine, not espresso grind. See full grind size guide.
2. Worn or misseated rubber gasket
Symptoms: steam or liquid escaping from the threaded joint between top and bottom chambers. Coffee won't flow upward because pressure is lost.
Fix: Inspect the rubber ring inside the top chamber. If cracked, hardened, or misshapen — replace it. Replacement gaskets are cheap and widely available. Make sure it's properly seated before brewing.
3. Safety valve activating
Symptoms: hissing from the small valve on the side of the bottom chamber, steam shooting out sideways.
Fix: This is a safety feature activating due to over-pressure. Causes: grind too fine, grounds packed too tight, or filter clogged with old grounds. Grind coarser and ensure the filter basket is clean.
4. Assembly or heat issues
Check: Is the lid closed? Is the top section screwed on tightly? Is there sufficient water in the bottom (not below the 1cm mark)? Is there actual heat — induction users need an induction-compatible Moka pot.