Coffee Grind Size Chart: How Grind Size Affects Coffee Flavor

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).

Pre-ground coffee is readily available, so why grind your beans at home? The primary reason is that whole beans have a longer shelf life than ground coffee. Roasted whole beans contain carbon dioxide, which prevents oxidation and staling, and they can keep for about two weeks at room temperature. Once ground, more of the beans’ surface area is exposed to oxygen, causing the grounds to lose flavor. Ground coffee keeps only a few days, so it’s best to buy it in very small amounts.

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.

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.)

The blade grinder is the most common and affordable type of coffee grinder. It works by chopping beans with a blade—like a tiny food processor. The downside of a blade grinder is that it creates coffee particles of different sizes; in the process of grinding beans to a medium or coarse texture, some particles inevitably become fine and powdery. When the coffee particles are all different sizes, they have different extraction rates, resulting in an uneven-tasting cup. Additionally, the friction of the blade creates heat, which can damage the flavor of the beans.

Instead of chopping the beans with blades, a burr grinder (aka burr mill) crushes the beans between two rough discs called burrs. This method produces a more uniform consistency, since the space between the burrs determines the particle size. Burr grinders come in a few different iterations: the old-fashioned manual grinder (which looks kind of like a hand-cranked pepper mill), the electric flat burr grinder (more adjustable; popular for commercial use), and the electric conical burr grinder (quieter; popular for home use).

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