If your coffee tastes wrong and you cannot work out why, grind size is almost always the culprit. It matters more than your machine, more than your water, and considerably more than the price of your beans.
Here is how to get it right.
Why grind size matters so much
Brewing is extraction — hot water dissolving flavour out of coffee. Finer grounds have more surface area, so water pulls flavour out faster. Coarser grounds extract slower.
Get it wrong in either direction and you taste it immediately:
- Too coarse — water rushes through and under-extracts. The cup tastes sour, thin, and salty. People often mistake this for the beans being bad.
- Too fine — water crawls through and over-extracts. The cup tastes bitter, harsh and drying.
The sweet spot is where the coffee tastes sweet and balanced. That is genuinely the test.
The grind chart
| Brew method | Grind | Looks like | Brew time |
|---|---|---|---|
| Espresso | Fine | Caster sugar | 25–30 sec |
| Moka pot | Fine–medium | Between caster and table salt | 4–5 min |
| AeroPress | Medium-fine | Table salt | 1–2 min |
| V60 / pour over | Medium | Coarse sand | 2–4 min |
| Filter / batch brew | Medium | Coarse sand | 4–6 min |
| French press | Coarse | Sea salt flakes | 4 min |
| Cold brew | Very coarse | Cracked peppercorns | 12–18 hrs |
Diagnosing your cup
Change one thing at a time, and always taste before you adjust.
Sour, sharp, watery? Under-extracted. Grind finer. Only if that fails should you look at water temperature or brew time.
Bitter, dry, ashy? Over-extracted. Grind coarser.
Espresso running in under 20 seconds? Too coarse. Tighten the grind.
Espresso choking or taking 40+ seconds? Too fine. Open it up.
Small adjustments. One notch on your grinder at a time — espresso especially is sensitive enough that a single step changes the shot noticeably.
Burr grinder or blade grinder?
Blade grinders chop coffee at random, producing a chaotic mix of dust and boulders. The dust over-extracts and the boulders under-extract, in the same cup, at the same time. You end up with something both bitter and sour.
Burr grinders crush beans between two surfaces at a set distance, so the particles come out roughly uniform. That consistency is the entire point.
If you are choosing between better beans and a burr grinder, buy the grinder. It will do more for your coffee.
Roast level changes things too
Darker roasts are more soluble — they give up flavour more readily — so they often want a slightly coarser grind than a lighter roast on the same brewer. If you switch from Almond Blossom to the darker Starry Night and your espresso suddenly tastes harsh, back the grind off a notch before you blame anything else.
Fresh beans also behave differently to stale ones. Coffee degasses as it ages, which changes how water moves through the bed. Beans two weeks off roast will need a different setting to beans two months old — another argument for buying smaller amounts more often.
Common questions
Can I use pre-ground coffee? You can, but it is ground to one setting — usually a compromise — and it goes stale within days. Whole beans ground fresh is the single biggest upgrade available.
How long does ground coffee stay fresh? Meaningfully, a few days. Whole beans hold up for weeks. See our storage guide.
Do I need to change grind for milk drinks? Not the grind itself, but darker, chocolatey blends cut through milk better. That is why Starry Night is the more popular choice for flat whites.
Why does my grind setting keep drifting? Coffee oils build up in the burrs and change the effective spacing. Clean your grinder every few weeks.
Chambers beans are roasted in Sydney and dispatched fresh, so you are dialling in coffee that is actually worth dialling in. Shop the range.