Coffee Grind Size Chart — Particle Diameter by Brew Method
Coffee grind size by method: espresso 200–300μm, AeroPress 350–800μm, pour-over 400–700μm, drip 500–800μm, French press/cold brew 1000–1400μm. Finer grind = more surface area = faster extraction.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Espresso grind range | 200–300 | μm (median particle diameter) | Finest common grind; high resistance needed for 9 bar pressure |
| AeroPress grind range | 350–800 | μm | Wide range reflects flexible brew time (30 sec to 4 min) |
| Pour-over grind range | 400–700 | μm | Gravity flow through paper filter; finer end for fast draw-down |
| Drip machine grind range | 500–800 | μm | Flat-bottomed baskets use medium; cone baskets use finer end |
| French press grind range | 1000–1400 | μm | Coarse to avoid passing through metal mesh filter |
| Cold brew grind range | 1000–1400 | μm | Long steep (12–24h) compensates for low extraction rate at coarse size |
| Turkish/ibrik grind | 100–200 | μm | Finest of all; coffee is not filtered — grounds settle in cup |
| Moka pot grind range | 250–350 | μm | Slightly coarser than espresso to account for lower pressure (1.5 bar) |
Grind size is the most frequently adjusted variable in coffee brewing. Every method has a target extraction window (time and rate at which water moves through or steeps with coffee), and grind size is the primary mechanism for hitting that window. The relationship is direct: finer grinding increases surface area and extraction rate; coarser grinding decreases both.
Grind Size Reference Chart
| Brew Method | Particle Size (μm) | Visual Reference | Extraction Time |
|---|---|---|---|
| Turkish/ibrik | 100–200 | Powdery, like flour | 3–4 min boil |
| Espresso | 200–300 | Fine table salt | 25–30 seconds |
| Moka pot | 250–350 | Fine table salt, slightly coarser | 4–5 minutes |
| AeroPress (short) | 350–500 | Fine–medium | 1–2 minutes |
| AeroPress (long) | 600–800 | Medium | 3–4 minutes |
| Pour-over | 400–700 | Medium | 2.5–4 minutes |
| Drip machine | 500–800 | Medium | 4–6 minutes |
| Clever dripper | 600–800 | Medium | 4–5 minutes |
| French press | 1000–1400 | Coarse, like raw sugar | 4 minutes |
| Cold brew | 1000–1400 | Coarse | 12–24 hours |
How Grind Size Affects Extraction
Extraction yield (the percentage of coffee mass that dissolves into water) follows a dose-response curve with grind size:
| Grind error | Typical result | Flavor character |
|---|---|---|
| Too fine | Over-extraction (>22% yield) | Bitter, astringent, dry finish |
| Correct range | Target extraction (18–22% yield) | Balanced: sweetness, acidity, body |
| Too coarse | Under-extraction (<18% yield) | Sour, thin, hollow, grassy |
The SCA target extraction yield for specialty coffee is 18–22% for most methods. This is measured by TDS (total dissolved solids) and is affected by grind size, water temperature, brew ratio, and agitation.
Particle Size and Burr Quality
Consumer-grade blade grinders produce highly irregular particles: a 300μm target setting may yield particles ranging from 50μm to 2,000μm. This bimodal distribution causes simultaneous over- and under-extraction.
Quality burr grinders produce much tighter distributions. High-end flat burr grinders (e.g., EK43) are used for pour-over and filter because they minimize fines. High-end conical burr grinders (e.g., Comandante, Fellow Ode) produce slightly more fines, which some baristas prefer for espresso body.
Temperature and Grind Interaction
Beans grind differently at different temperatures. Warmer beans are softer and produce more fines. Freshly roasted beans (within 1–7 days of roast) contain CO₂ that can affect extraction consistency. Many specialty roasters recommend a 7–21 day rest post-roast before espresso to allow CO₂ to off-gas sufficiently.
Related Pages
Sources
- SCA Extraction Research — Grind Analysis
- Illy A, Viani R (2005) Espresso Coffee: The Science of Quality
- Kuhn M et al. (2017) Controlled, small-scale coffee grinding studies. Food & Function
- Cameron M et al. (2020) Systematically Improving Espresso. Matter
Frequently Asked Questions
Why does grind size matter so much for coffee extraction?
Grind size determines the surface area of coffee exposed to water. Finer grinding creates more particles with more total surface area — water contacts more coffee per second, accelerating extraction of soluble compounds. Coarser grinding reduces surface area and slows extraction. Each brew method has a target extraction time; grind size is the primary variable used to hit that target. Too fine for the method = over-extraction (bitter, astringent). Too coarse = under-extraction (sour, thin).
How does grinder type affect grind quality beyond particle size?
Grinder type affects the particle size distribution — the uniformity of the grind. Blade grinders produce bimodal distributions with many 'fines' (ultra-small fragments) and 'boulders' (large chunks) mixed together. Burr grinders (flat or conical) produce narrower distributions where most particles cluster around the target size. Fines over-extract and boulders under-extract in the same brew, contributing to muddy, unbalanced flavor. Specialty-grade brewing typically requires burr grinders.
What is the practical difference between flat and conical burrs?
Flat burr grinders use two horizontal disc-shaped burrs rotating in the same plane — they tend to produce a narrower, more bimodal particle distribution with distinct 'boulders' and 'fines' but overall very consistent median particle size. Conical burr grinders use a tapered inner burr inside a ring outer burr, producing a slightly wider distribution but with more 'fines' that some argue improve espresso body. In practice, both can produce excellent results; the differences are most apparent at the finest espresso settings.
How should I adjust grind size when my espresso is running too fast or too slow?
If espresso extracts too fast (under 20 seconds), grind finer — smaller particles increase resistance, slowing flow rate. If it extracts too slowly (over 35 seconds), grind coarser — larger particles reduce resistance, speeding flow. Change grind size in small increments (one number on your grinder's scale) and pull a test shot before changing again. If adjusting grind does not fix the problem, check dose weight, distribution in the basket, and tamping pressure first.