700
µm
6
5
min
93
°C
16
ml/g
320
ml
700
µm
6
5
min
93
°C
16
ml/g
320
ml
Grind size is one of the most critical variables in brewing coffee, directly influencing extraction rate, flavor balance, and overall cup quality. When coffee grounds are too fine for a given brew method, water passes through slowly, over-extracting bitter and harsh compounds. When grounds are too coarse, water flows too quickly, under-extracting the coffee and producing a sour, weak, or watery cup.
The Coffee Grind Size Calculator helps you match your coffee grind to your brewing method. Each method has an optimal particle size range measured in micrometers (µm), and this calculator provides a target size along with a standardized grind setting on a 1–10 scale — from extra-fine (1) to extra-coarse (10).
Here is a quick guide to how grind size maps to brew methods:
Turkish Coffee (Extra Fine, ~200µm, Setting 1): The finest grind of all, resembling talc or very fine flour. The coffee is not filtered and simmers directly in water, so extremely fine particles are required for proper extraction.
Espresso (Fine, ~300µm, Setting 2): Slightly coarser than Turkish but still very fine, resembling fine table salt. This grind creates the resistance necessary for a pump-driven espresso machine to extract the signature concentrated shot in 25–30 seconds.
Moka Pot (Medium-Fine, ~500µm, Setting 4): Coarser than espresso to prevent clogging the moka pot's filter basket while still delivering a strong, rich brew as steam pressure pushes water through the grounds.
Drip / Pour Over (Medium, ~700µm, Setting 5–6): The most versatile grind size, suitable for drip coffee makers and most pour-over methods like the Hario V60 or Chemex. Resembles coarse sand.
French Press (Coarse, ~1000µm, Setting 7–8): A coarse grind is essential for French press. Fine grounds pass through the metal mesh filter, create excessive sediment, and over-extract during the 4-minute steep.
Cold Brew (Extra Coarse, ~1200µm, Setting 9): The coarsest grind for any standard brew method. Because cold water extracts much more slowly, coarser grounds prevent over-extraction over the 12–24 hour steep time.
The calculator also provides recommended water temperature and brew time for each method to give you a complete starting point for a great cup of coffee.
The calculator maps your selected brew method to a predefined optimal range of parameters derived from industry standards and specialty coffee research. The target particle size is expressed in micrometers (µm) — the diameter of the coffee particle produced by the grinder. The grind setting on a 1–10 scale provides a relative reference, since actual grinder dial numbers vary by brand and model. Water temperature and brew time are provided as starting recommendations based on SCA standards and specialty coffee best practices.
Use these results as your starting baseline. If your coffee tastes bitter or harsh, grind slightly coarser (increase setting by 0.5). If it tastes sour, weak, or watery, grind slightly finer (decrease setting by 0.5). Small adjustments make a significant difference. Note that grinder models vary — a setting of 5.5 on one grinder may produce a very different particle size than on another. Use a calibration reference or a particle size distribution tool for precision work.
Inputs
Results
For 18g of coffee in an espresso machine, target ~300µm particle size (setting 2/10). Brew at 93°C. Shot should extract in approximately 25–30 seconds (0.5 min).
Inputs
Results
For 30g in a French press, target ~1000µm coarse grind (setting 7.5/10). Brew at 95°C for 4 minutes before pressing the plunger.
Grind size controls the surface area of coffee exposed to water, which directly affects how quickly flavors are extracted. Too fine means over-extraction (bitterness); too coarse means under-extraction (sourness). Getting grind size right is arguably the single most impactful variable in coffee quality.
Burr grinders — both flat burr and conical burr — produce far more consistent particle sizes than blade grinders. Blade grinders chop randomly, creating a wide distribution of sizes that leads to uneven extraction. For quality coffee, always use a burr grinder.
Pull a test shot and time it. A standard double espresso (18g in, ~36g out) should extract in 25–30 seconds. If it takes longer, grind coarser. If it extracts too quickly, grind finer.
No. Espresso-ground coffee in a French press will clog the plunger, create excessive sediment, and drastically over-extract, producing a bitter and sludgy cup. Always use coarse grind for French press.
AeroPress is very versatile. A medium-fine grind (similar to espresso but slightly coarser) works well for 1–2 minute recipes. A coarser grind works for inverted or longer-steep methods. Experiment to find your preference.
Finer grinds extract more quickly and may result in slightly higher caffeine extraction efficiency. However, for a given dose and brew time, the difference in caffeine between fine and coarse grinds within the correct range for a method is minimal.
Grind residue and coffee oils build up over time, turning rancid and negatively affecting flavor. Clean your burr grinder every 1–2 weeks with a grinder cleaning tablet or by disassembling and brushing the burrs. Rinse-free grinder cleaning products are widely available.
High humidity causes coffee grounds to absorb moisture, which can cause them to clump and slow extraction — effectively acting as a finer grind. Many baristas adjust their grind coarser on humid days to maintain consistent shot times.
A medium-fine grind — slightly coarser than espresso — is best for a moka pot. Using espresso grind in a moka pot can clog the filter and cause dangerous pressure buildup. Target around 500µm or setting 4/10.
Pre-ground coffee is convenient but goes stale much faster than whole beans. Ground coffee loses peak freshness within 15–30 minutes of grinding due to oxidation. For the best cup, grind fresh immediately before brewing.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
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