Fines are the very small particles produced alongside your target grind size. Every grinder makes them; the question is how many.
Why they matter
Extraction depends on surface area. A fine particle extracts almost instantly and then keeps going into bitterness, while a boulder is still getting started. A grind with lots of fines gives you over-extraction and under-extraction in the same cup.
Where they help
Espresso. Fines contribute to flow resistance and to body, and a shot ground with no fines at all would run fast and thin. This is part of why conical burrs, which produce more fines, are traditional in espresso.
Where they hurt
French press. A metal mesh cannot hold them back, so they end up as sediment and keep extracting in the cup — which is why the second half of a cafetière tastes harsher.
Pour-over. They migrate down and clog the filter bed, stalling the brew and causing uneven drainage.
Reducing them
A better grinder, principally — burr quality and alignment determine the fines fraction more than anything else. Sifting is possible and tedious. Grinding coarser reduces them somewhat.
Freezing beans before grinding genuinely reduces fines, since cold coffee fractures more cleanly.
Last reviewed 8 August 2026