Almost all moka problems come down to two or three recurring causes. Here’s the guide to go from “I can never get it right” to a reliable cup.

The coffee is bitter

  • Causes: grind too fine, flame too high, or coffee left on the heat after it’s done brewing.
  • Fixes: grind a bit coarser, use a medium-low flame, and take it off the heat as soon as you hear the gurgle.

Metallic taste

  • Causes: a new moka that hasn’t been “seasoned,” or residue/oxidation from incorrect washing.
  • Fixes: brew a few throwaway coffees with a new moka; wash with water only, never detergent or the dishwasher.

The coffee is weak or watery

  • Causes: grind too coarse, too little coffee, or too large a pot used half-full.
  • Fixes: grind finer, fill the filter completely, use the right size.

Spitting and splattering

  • Causes: flame too high, a worn gasket, or a dirty filter plate.
  • Fixes: lower the flame, check the gasket and the perforated plate, keep everything clean.

It takes too long (or nothing comes out)

  • Causes: grind too fine (clogging), too little water, or a blocked valve/filter.
  • Fixes: coarser grind, water up to the valve, clean the valve and the little holes.

Quick reference

ProblemLikely causeFix
BitterFine grind / high flameCoarser grind, lower flame
MetallicNot seasonedThrowaway coffee, no detergent
WeakCoarse grind / too little coffeeFiner grind, full filter
SpittingHigh flame / gasketLower flame, check gasket

Keep the flame quite low, since good coffee takes patience. A high flame overheats the moka’s chamber, so the coffee that comes out — already running hot — risks scorching.

Frequently asked questions

Why is my moka coffee bitter? Grind too fine, flame too high, or too much time on the heat.

Why does it have a metallic taste? A new moka that hasn’t been seasoned, or one that’s been washed incorrectly.

Why is it weak? Grind too coarse or the filter isn’t full.