Coffee grind size, explained

How grind size controls extraction, a starting-point guide by brew method, and why grinder-aware grind settings beat vague labels like 'medium'.

Grind size is the single biggest lever you have over a brew. It controls how much surface area the water can reach and how fast water flows through the coffee bed — which together set your extraction.

Finer vs coarser

• Finer grind → more surface area + slower flow → more extraction. Push too far and you over-extract: bitter, drying, harsh.
• Coarser grind → less surface area + faster flow → less extraction. Too coarse and you under-extract: sour, weak, salty, thin.

Most “bad” cups are an extraction problem, and grind is usually the first thing to adjust.

Starting points by method

From finest to coarsest:

• Espresso — very fine, like powdered sugar.
• AeroPress — fine to medium, depending on recipe.
• V60 / pour over — medium-fine, like table salt.
• Kalita / Chemex — medium.
• Clever / immersion — medium to medium-coarse.
• French press — coarse, like breadcrumbs.
• Cold brew — very coarse.

These are starting points. Dial in from there based on taste and brew time.

Dial in by taste

Adjust one variable at a time:

• Cup tastes sour, weak, sharp → grind finer (raise extraction).
• Cup tastes bitter, dry, hollow → grind coarser (lower extraction).
• Pour over running too fast or too slow? Grind is usually why.

”Medium” means nothing without your grinder

A “medium” grind on one grinder is nothing like “medium” on another. What’s useful is a number tied to your specific grinder — “setting 5 on a Fellow Ode Gen 2” or “18 clicks on a Comandante.” That’s repeatable; “medium” is not.

This is why BeanBench records grind as a numeric setting with grinder context. Log the grinder and the number, and your next brew of the same coffee starts from a real reference point instead of a guess.