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The Impact of Fine Coffee Grounds on Flavor and Texture - Recommended Grind Coarseness for Single-Origin Coffee

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, When coffee beans are ground into coffee powder, whether using a premium grinder worth tens of thousands or an entry-level grinder costing a few hundred, the appearance of fine grounds is currently unavoidable. So naturally, brewing follows the grinding process—after all, that's what everyone does. Yet, the resulting coffee often tastes astringent and bitter...

When coffee beans are ground into powder, whether using a high-quality grinder worth tens of thousands of yuan or an entry-level grinder costing a few hundred yuan, the production of fine particles is currently unavoidable. Therefore, it's natural to proceed with brewing after grinding, since that's what everyone does. Yet, the resulting coffee often tastes astringent and bitter...

The Cause of Fine Particles

After roasting, coffee beans undergo a certain degree of expansion. When moisture is dried, the beans acquire a certain brittleness. When subjected to the pressure between two grinding discs, coffee beans first crack apart before being ground into particles. The cracking process is precisely what causes the production of fine particles.

The Impact of Fine Particles on Coffee Flavor

Many people have a poor impression of fine particles, believing they are the source of filter clogging and the main culprit of over-extraction. Sieving out the fine particles seems to be the best solution to this problem.

After sieving out the fine particles and proceeding with brewing, the filter no longer clogs, and the water flow becomes even. The coffee's taste is cleaner, and the acidity is brighter. However, something always feels missing. Indeed, it's precisely the explosive aroma, sweetness, and more impressive layering that fine particles bring.

FrontStreet Coffee has always emphasized that extracting a cup of coffee only requires uniform extraction to produce a good cup of coffee, and uniform techniques ensure every inch of coffee grounds absorbs water evenly without bias. However, if we discuss coarse and fine particles separately, under the condition of even water pouring, the extraction rate of fine particles will inevitably be higher than that of coarse particles.

But when properly controlled, this is actually a good thing. For example, the fine particle rate of the Fuji Mini grinder is about 12%. Under the set grind setting, with even water pouring, the extraction rate of 12% fine particles is slightly higher (assume 22%), while the remaining 88% of coarse particles has a slightly lower extraction rate (assume 17.5%). This yields a coffee extraction rate of approximately 18.04%. This cup of coffee will exhibit rich layering and flavor.

Of course, if control is not precise and the extraction rate of fine particles exceeds 22%, that 12% of fine particles will become the source that ruins your coffee. For example, if the fine particle extraction rate is 23% and the coarse particle extraction rate is 17.8%, although the overall extraction rate is 18.4% (within the Golden Cup range), the bitter taste extracted from fine particles cannot be masked.

"Fine particles can make or break your coffee"

If using an EK43 grinder, at the same coarseness level, the amount of fine particles is relatively small, about 5%. This way, the impact of fine particles on the overall coffee is much weaker, but stability is significantly higher.

How FrontStreet Coffee Handles Fine Particles

Today, many friends still enjoy using the Fuji Mini grinder because they appreciate its uniform coarse particles and the rich flavor layering brought by fine particles.

There are also friends nicknamed "over-extraction masters" who choose to sieve out fine particles, after all, nobody likes a coffee with heavy bitterness.

FrontStreet Coffee tends to retain fine particles but won't choose grinders that produce too many fine particles, because coffee lacking fine particles truly loses much flavor, resulting in a hollow sensation. However, when there are too many fine particles, the uncertainty factor increases, and FrontStreet Coffee leans toward stable production.

If your grinder produces too many fine particles, you can do some extra work: sieve out the fine particles, then add back some of the sieved fine particles. This reduces the amount of fine particles while preserving their flavor.

Some friends also add fine particles back before the final water pour after sieving them out. This method also ensures you can brew coffee with good flavor while avoiding local over-extraction.