Why grind size matters
When you grind coffee, you're breaking beans into particles that water flows through and extracts from. Finer particles have more surface area, so they extract faster. Coarser particles have less surface area, so they extract slower.
Every brew method has a target extraction time. The grind size you use should produce the right extraction rate for that target. If you use espresso-fine grounds in a French press, the 4-minute steep will massively over-extract and taste unbearably bitter. If you use French press-coarse grounds in an espresso machine, the 25-second shot will barely extract anything and taste like sour water.
Grind size chart
| Grind level | Visual reference | Methods |
|---|---|---|
| Extra fine | Flour or powdered sugar | Turkish coffee |
| Fine | Icing sugar / very fine sand | Espresso |
| Medium-fine | Table salt | Moka pot, AeroPress (espresso-style) |
| Medium | Beach sand / sea salt | Drip machine, AeroPress (standard), Siphon |
| Medium-coarse | Rough sand | V60, Kalita Wave |
| Coarse | Raw cane sugar | Chemex, French press |
| Extra coarse | Cracked peppercorns | Cold brew |
How to tell if your grind is right
The best feedback is the taste of the coffee combined with the extraction time. For most methods:
- Too fine: Bitter, harsh, over-extracted. Extraction time longer than target. Slow flow or clogged filter.
- Too coarse: Sour, thin, weak, under-extracted. Extraction time shorter than target. Very fast flow.
- Just right: Balanced, sweet, full-bodied. Hits the target extraction time.
Grinder quality and consistency
Consumer blade grinders produce inconsistent particle sizes — a mix of very fine dust and large chunks. This makes the resulting coffee taste simultaneously over- and under-extracted (muddy, with competing sour and bitter notes). Even an entry-level burr grinder produces significantly more consistent particle sizes and dramatically better coffee.
If you're using a burr grinder, adjust in small increments — one or two numbers at a time. Each step changes the grind meaningfully. Jumping across multiple settings at once makes it impossible to know which change caused the improvement.
Method-specific notes
Espresso
Espresso grind requires the most precision of any method. A single step on most grinders changes shot time by 3–5 seconds. Dial in by adjusting in very small increments and measuring shot time and yield precisely.
AeroPress
The AeroPress is the most flexible method — it works well from medium-fine to medium depending on steep time and plunge speed. Longer steeps with coarser grinds, shorter steeps with finer grinds.
French press
Use a coarse grind and press at exactly 4 minutes. Pour immediately after pressing — leaving the plunger down allows the grounds to continue extracting even after pressing.