Coffee Ratio LabFix My Coffee: Instant Troubleshooter for Bitter, Sour, Weak or Muddy Coffee
Bitter coffee is usually over-extracted (grind coarser, use slightly cooler water, shorten the brew). Sour coffee is under-extracted (grind finer, use hotter water, brew longer). Weak coffee needs more coffee per ml of water. Choose your brewer and problem below for fixes ranked for your exact method.
2. What's wrong? (pick all that apply)
How this troubleshooter works
Almost every coffee problem comes from one of five things: grind size, ratio, water temperature, brew time or freshness. The troubleshooter combines general extraction rules with fixes specific to your brewer, and puts the most likely fix first. Change one thing at a time so you know what made the difference.
Bitter vs sour: the extraction rule
| Taste | Meaning | Main fix |
|---|---|---|
| Sour, sharp, salty, thin | Under-extracted | Grind finer, hotter water, longer brew |
| Bitter, dry, harsh, hollow | Over-extracted | Grind coarser, cooler water, shorter brew |
| Both bitter and sour | Uneven extraction | More even grind, gentler pouring |
| Weak but pleasant | Too little coffee | More coffee per ml of water |
More detail in our bitter coffee fix-it chart and grind size chart.
Frequently asked questions
Why does my coffee taste bitter?
Usually over-extraction: the grind is too fine, the water too hot, or the brew too long. Old coffee and dirty equipment also add bitterness.
Why does my coffee taste sour?
Usually under-extraction: grind too coarse, water too cool, or brew too short. Light roasts are especially prone to sourness.
Why is my coffee weak?
Most often there's simply too little coffee for the amount of water. Weigh your coffee and aim for about 1:15–1:16.
What should I change first?
Grind size. It has the biggest effect on taste for almost every brewing method.
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