# The Physics of Grind Size: Why Particle Size Changes Everything
When you grind coffee, you are not just reducing bean size. You are defining the contact surface area available for water to dissolve flavor compounds. Too fine, and the water over-extracts bitter compounds. Too coarse, and water passes through without enough resistance, producing a weak and sour cup. The grind converter gives you the exact range for each method.What determines the correct grind size?
Extraction method: Pressure, contact time and filter type dictate the optimal micron range for each brewing method.
Grinder uniformity: A high-end burr grinder produces homogeneous particles; a blade grinder generates fine powder and large chunks simultaneously.
Bean freshness: Freshly roasted coffee contains more CO2 and may need a slightly coarser grind than the same coffee aged a few weeks.
Taste calibration: The palate is the final instrument. The chart is your starting point; flavor is your destination.
| Method | Microns | Tactile reference | Contact time |
|---|---|---|---|
| Ibrik (Turkish) | 100-300 μm | Talc / Fine flour | 3-5 min boiling |
| Espresso | 300-500 μm | Fine salt | 25-30 sec |
| Moka / AeroPress | 500-700 μm | Table salt | 3-4 min |
| V60 / Filter | 700-900 μm | Granulated sugar | 2:30-3:15 min |
| Chemex / Clever | 900-1200 μm | Coarse sand | 3:30-4:30 min |
| French Press | 1200-1500 μm | Coarse salt | 4 min immersion |
| Cold Brew | 1500+ μm | Peppercorns | 12-24 h cold |
Golden rule for new coffees
When you open a new coffee, always start at the midpoint of the recommended range for your method. From there, adjust by taste one click at a time. Keep notes on each adjustment to build a reference log of your favorite coffees with each grinder.