What Grind Size for Each Brewer

There is one rule underneath every grind recommendation, and once you have it you can work out any brewer you have never used: the longer the water sits on the coffee, the coarser the grind. Everything below is that sentence applied.

Grinding finer makes more surface area, so the coffee gives up its flavour faster. If the brew is also long, you extract too much and get bitterness and a drying finish. Grind coarser than the method wants and the water runs out before enough has dissolved, which tastes sour and thin. The two faults are opposites and people routinely mistake one for the other.

The scale, from coarse to fine

Cold brew, 12 to 24 hours

The coarsest grind anything uses, roughly like raw sugar. The contact time is enormous, so the grind has to be slow to give anything up. Grind cold brew like filter coffee and you will get something muddy and over-extracted no matter how cold the water was.

French press, 4 minutes

Coarse, similar to sea salt. The mesh in a Chambord is a strainer, not a filter, so anything fine enough to pass through ends up in the cup as sludge. The other reason to stay coarse is that the coffee sits in the water the whole time and only stops extracting when you pour it out.

Chemex, 4 to 5 minutes

Medium-coarse. The Chemex uses a paper 20 to 30 percent heavier than a normal filter, which slows the flow considerably, so it needs a coarser grind than its shape suggests. Grind it like a V60 and it will stall.

Drip machines, 4 to 6 minutes

Medium, the texture of sand. This is what supermarket pre-ground is cut to, which is why pre-ground is tolerable in a drip machine and poor in everything else.

Pour over, 2 to 4 minutes

Medium to medium-fine, and this is where the dripper's shape matters. A V60 has one large hole and drains fast, so it wants a finer grind to slow the water down. A Kalita Wave has three small holes that restrict flow themselves, so it wants slightly coarser.

AeroPress, 1 to 2 minutes

Fine to medium depending on how you use it. The AeroPress is the most forgiving brewer here because the plunger forces the water through regardless, so a grind that would stall a dripper still works.

Moka pot, 3 to 5 minutes

Fine, but not espresso fine. A moka pot builds only 1 to 2 bar, nothing like an espresso machine's nine, and a true espresso grind will choke it and force steam through the safety valve.

Espresso, 25 to 30 seconds

The finest, like flour with some grit. Nine bars of pressure through a 20-second contact time needs enormous surface area. This is also the least forgiving: a change too small to see in the grounds moves the shot by five seconds.

Reading the cup instead of the grind

You cannot judge a grind by looking at it once you are past the obvious extremes. Judge it by taste, and there are only two directions.

Sour, thin, watery, finishes fast. Under-extracted. Grind finer, or brew longer.

Bitter, harsh, drying, hollow in the middle. Over-extracted. Grind coarser, or brew shorter.

Change one thing at a time and give it a full step. Half a click tells you nothing.

Why the same setting is not the same grind

Grinder settings are not a shared scale. Number 15 on one machine is nothing like 15 on another, and even two units of the same model differ slightly. Any recommendation phrased as a number rather than a description is worthless to you.

Roast level shifts it too. Dark roasts are more brittle and shatter into more fines at the same setting, so the same number grinds effectively finer. Coming from a light roast to a dark one, expect to go a step coarser.

Weighing beats guessing, and it is cheap

Grind size only means something against a fixed dose and a fixed brew time. If your dose moves by two grams between brews, you cannot tell whether a change in the cup came from the grind or from the scoop, and you will chase the wrong variable for weeks.

This is the entire argument for a coffee scale, and it is a stronger one than the price suggests. Fix the dose, fix the water, and the grind becomes the only thing left moving, which is what makes it adjustable at all.

Pre-ground coffee, and why it only suits one brewer

Supermarket pre-ground is cut to a medium drip grind, because that is the largest market and the most forgiving method. In a drip machine it is genuinely fine. In a French press it is too fine and comes through the mesh as sludge; in an espresso machine it is far too coarse and the shot gushes through in eight seconds.

There is a second cost that has nothing to do with size. Ground coffee has enormously more surface area exposed to air than whole beans, and it goes stale in days rather than weeks. Buying good beans and grinding them a week at a time throws away most of what you paid for.

A working method for a new brewer

Start in the middle of the range for that method. Brew it, and time how long the whole thing takes. Then compare against the target: four minutes for a press, two to four for pour over, twenty-five to thirty seconds for espresso.

If it finished early, grind finer. If it dragged, grind coarser. Adjust in full steps, not fractions, and change nothing else. Three brews is usually enough to land it, and then you leave it alone until you change beans.

When you do change beans, expect to re-dial. A new roast level, a new origin or simply a fresher bag will move the brew time at the same setting, which is normal and not a sign anything is wrong.

The part the grinder decides

All of this assumes your grinder produces a size at all. A blade grinder makes several sizes at once, so no setting is correct: some of your dose is over-extracting while the rest under-extracts. If your coffee tastes bitter and sour at the same time, that is the signature, and it is a grinder problem, not a grind problem.