What is grind size? Why fine or coarse changes your coffee

How does grind size change the taste?

Grind size changes taste by changing how much gets extracted. Perfect Daily Grind explains that a coarser grind slows extraction because there is less surface area. Fruity acids come out early, then sweetness, and bitterness last.

So a grind that is too coarse tends to taste sour and thin. A grind that is too fine tends to taste bitter. Honest Coffee Guide gives the same rule for pour-over: if it tastes bitter, go coarser; if it tastes sour, go finer.

Those two failures are called under-extraction and over-extraction.

What grind size should I use for each brew method?

Use a range for your method, then adjust by taste. BrewMark's coffee grind size chart lists the ranges for every common method, from espresso to cold brew.

Treat any chart as a starting point. Honest Coffee Guide notes that grind size "cannot be accurately defined with a simple numerical value," because every grinder produces a spread of particle sizes. Published micron ranges also differ from one source to the next.

Why doesn't my grinder's number match the recipe?

Because grinder numbers are not a shared unit. Honest Coffee Guide puts it plainly: the "2" setting on one grinder is not the same as the "2" on another. It adds that two grinders from the same factory can vary.

Words do not help much either. One person's "medium-fine" is another person's "medium." That is why a recipe written for a Comandante C40 in clicks rarely translates cleanly to a Baratza Encore.

BrewMark solves this with the grind index, a shared 0 to 100 scale. Each grinder's dial is mapped onto it using anchor points for known methods:

The grind converter uses this scale to turn a setting on one grinder into a setting on yours. Each grinder page on BrewMark also has its own settings chart for every method.

Does grind consistency matter as much as grind size?

It matters a lot, and some argue it matters as much. Honest Coffee Guide warns that too many fine particles over-extract, while too many large "boulders" under-extract. For pour-over, its advice is a burr grinder designed for pour-over or drip.

Coffee ad Astra makes a related point about flow. It says the uniformity of a grinder's particle distribution "will directly affect flow uniformity," because it governs the gaps water flows through. Uneven gaps mean uneven extraction.

The spread of sizes has its own term, grind size distribution, and the dust at the small end is called fines.

Can you just grind finer to extract more?

Only up to a point, and where that point sits is debated. Coffee ad Astra tested this with pour-over. It found astringency appeared when grinding finer, and suggested the cause "might be the combination of long brew time and finer grind size."

Upgrading the grinder did not remove the limit. After moving to a Weber EG-1, the author gained about 1% in average extraction over a Baratza Forté. The bigger change was that brews "suddenly tasted much cleaner."

The practical lesson: a better grinder tends to buy clarity more than the ability to grind much finer.

How does grind size affect which grinder to buy?

It decides whether a grinder covers your methods at all. Not every grinder's range reaches both espresso and French press, so check before you buy. Each grinder page on BrewMark shows which methods its dial covers, with a setting for each.

Start with the methods you brew. The grinder finder narrows the catalog by method, and Baratza Encore vs Fellow Ode Gen 2 shows two popular filter grinders' dials side by side.