Why Grind Size Is the Most Important Variable
If your coffee tastes bitter, sour, or just flat, the grind is probably wrong. Grind size controls how quickly water extracts flavor from coffee — get it wrong and no amount of technique will save you.
The Science
Finer grinds expose more surface area, so water extracts compounds faster. Coarser grinds slow extraction down.
- Under-extracted (too coarse or too fast): sour, thin, lacking sweetness
- Over-extracted (too fine or too slow): bitter, astringent, harsh
- Just right: sweet, balanced, clean finish
Grind Size by Method
| Method | Grind Size | Looks Like |
|---|---|---|
| Cold brew | Extra coarse | Raw sugar |
| French press | Coarse | Sea salt |
| Drip / pour over | Medium | Table salt |
| AeroPress | Medium-fine | Fine sand |
| Espresso | Fine | Powdered sugar |
| Turkish | Extra fine | Flour |
Burr vs Blade Grinders
Blade grinders chop beans randomly, producing a mix of fine dust and large chunks. This causes uneven extraction — some particles over-extract while others under-extract in the same brew.
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