Grind size coffee: which grind suits your brewing method?

Same beans, same water, yet one cup tastes bitter and the next sour. Nine times out of ten, the difference lies in the grind size of your coffee. Grinding coffee is not a side issue: the size of the particles determines how quickly water extracts the flavor, and thus whether your cup is balanced. Below is which grind size corresponds to which brewing method, why that is, and — the part most guides skip — how to properly adjust your grinder in three cups.

Why grind size matters so much

Water extracts flavor from coffee through the surface of the particles. Fine grinding means a lot of surface area: the water pulls the flavor out quickly. Coarse grinding means little surface area: it goes slowly. Brewing is always a combination of grind size and contact time. Short contact requires fine, long contact requires coarse.

If it goes wrong, you taste it immediately. Too fine for your method, and the water keeps extracting past the sweet and chocolatey notes, towards dry and bitter: overextraction. Too coarse, and the water is gone before the flavor is extracted: thin, watery, and sour, in other words underextraction. Bitter means coarser, sour means finer. Remember those two rules and you already have the most important part.

Coffee grind size per brewing method

The order runs from shortest to longest contact time, and thus from fine to coarse. The comparisons with kitchen items are meant to be felt, not measured.

• Espresso — very fine, like powdered sugar or flour. The water goes through the coffee under about 9 bar pressure in 25 to 30 seconds. Every step on the grinder is noticeable here.
• Moka pot — fine, but coarser than espresso. The pressure is much lower, so espresso grind clogs the filter and tastes bitter and burnt.
• Filter coffee and pour-over — medium fine, like table salt or fine sand. A brew time of about two and a half to three and a half minutes is normal.
• Cafetière (French press) — coarse, like coarse sea salt. Four minutes steeping, then press down. Too finely ground coffee slips through the metal filter and makes the cup cloudy and bitter.
• Cold brew — extra coarse. The contact time is twelve to twenty-four hours; anything finer than coarse becomes muddy.

If you’re unsure which method suits you, first read our article about coffee brewing methods; the grind size follows naturally from that.

The three-cup test: adjusting your grinder in one morning

A table gives a starting point, not an answer. Every grinder counts differently, and every bean breaks differently. That’s why this test. It costs three cups of coffee and fifteen minutes, and after that you only need to repeat it when you change beans.

1. Fix everything except the grind size. Weigh your coffee and water, use the same temperature and the same time. If you change two things at once, you won’t know what caused the effect.
2. Choose a starting point. Unknown grinder? Set it in the middle of its range and use the table above to move in one direction.
3. Brew three cups: one at your starting point, one one step coarser, one one step finer. Time the extraction for each cup.
4. Taste them side by side, lukewarm. Warm hides mistakes; lukewarm clearly shows bitterness and sourness.
5. Move one step in the direction of the best cup, and note the number on the grinder. That is from now on your setting for this bean and this method.

Time is your measuring stick here. If an espresso extracts in fifteen seconds, you don’t even need to taste: too coarse. If a pour-over takes five minutes, you’re too fine. Those who want the numbers per method and per grinder at hand can find them worked out in our e-book.

Dark roast? Set your grinder one step coarser

This rarely appears in tables, and it explains many bitter cups. The darker a bean is roasted, the more brittle it becomes. A dark bean breaks more easily in the grinder and produces more fine dust at the same setting than a light bean. Moreover, it dissolves faster. Two reasons to grind coarser for a dark roast than the table says, and then adjust with the three-cup test.

This also applies to our Dark Roast, which is roasted beyond the second crack: if you grind it at an espresso setting meant for a light bean, the shot almost always extracts too slowly. One step coarser is usually enough.

Which grinder: blades or burrs

A grinder with blades (a "blade grinder") chops the beans randomly small. You get dust and chunks mixed: the dust overextracts, the chunks underextract, and the result tastes bitter and sour at the same time. A grinder with burrs (a "burr grinder") presses the beans between two discs at a fixed distance and delivers particles of roughly the same size. Only with that does setting a grind size make sense at all. A simple hand grinder with burrs is more than enough for filter and cafetière; for espresso you need more steps and more precision.

In all cases, grind just before brewing. Ground coffee loses its aroma much faster than whole beans, no matter how well you have adjusted the grind size.

Frequently asked questions

What grind size do I need for filter coffee?

For filter coffee and pour-over, use a medium-fine grind, about like table salt, with a brew time of two and a half to three and a half minutes.

Why does my coffee taste bitter?

Bitter coffee is usually overextraction due to too fine a grind; set the grinder one step coarser and change nothing else.

Do you have to grind a dark roast differently?

Yes, a dark roasted bean is more brittle and dissolves faster, so you generally grind it one step coarser than a light bean for the same brewing method.

A good grind size is not a number from a table but a setting you have found yourself, with the same beans as tomorrow. So make sure those beans are also there tomorrow: subscribe and save 10%, so you don’t have to readjust your grinder every month.