Does size matter? It certainly does! And so does what you do with it...
No matter your brew method, coffee-making involves extracting flavor (and caffeine) from coffee grounds. The finer you grind your coffee beans, the more you increase the exposed surface area of the grounds, resulting in faster extraction. That’s why coffee for espresso machines is ground fine, since the water from an espresso maker passes very quickly at high pressure through the grounds. Cold brew, on the other hand, is made with coarse-ground coffee, since this cold-extraction method allows the coffee to sit with the water for a much longer period of time (several hours, compared to espresso’s 30 seconds).
If you have a coffee grinder at home, you can experiment with different grinds to find what works best for you. To start, match your brewing type to the typical grind on this chart.
|Grind||Particle size in millimeters||Consistency similar to||Best for|
|Extra-coarse||1.5||Rock salt||Cold brew|
|Coarse||1||Coarse sea salt||French press, percolators|
|Medium||0.75||Beach sand||Pour-over, Chemex, drip coffee maker|
|Medium fine||0.5||Table salt||Moka pot (stovetop espresso), Aeropress, siphon brewer, pour-over cone|
|Fine||0.3||Fine granulated sugar||Espresso|
If your coffee tastes watery and acidic, you may be grinding your beans too coarsely. Try a finer grind, and see if that fixes the issue. If your coffee tastes overly bitter, you may be grinding too finely. A coarser grind may improve your brew. (Brew time and temperature will affect flavor as well.)