How fine should I grind for espresso?

Dialing in espresso is one of the most precise tasks in coffee brewing because the process relies on high pressure to force water through a tightly packed 'puck' of coffee. If your grind is too coarse, the water will pass through the coffee too quickly, resulting in an under-extracted, sour, and watery shot. If the grind is too fine, the water may struggle to pass through at all, leading to a bitter, over-extracted, or choked machine.

Achieving the perfect espresso grind is a process of trial and error. Start with a setting that feels like fine sand or table salt. When you pull a shot, you are looking for a specific flow rate—typically, a double shot should take between 25 and 30 seconds to yield about 36 to 40 grams of liquid from 18 grams of dry coffee. If the shot runs too fast, adjust your grinder to a finer setting; if it runs too slow, adjust it to be slightly coarser.

Consistency is just as important as size. A high-quality burr grinder is essential here because it ensures that all particles are roughly the same size. If your grinder produces a mix of very fine 'fines' and larger boulders, the water will channel through the path of least resistance, leading to uneven extraction and inconsistent flavor. This is why investing in a dedicated espresso grinder is often the most impactful upgrade for a home barista.

In practice, remember that your grind setting is not static. As coffee beans age, they lose moisture and change in density, meaning you will likely need to adjust your grinder slightly finer every few days to maintain the same extraction time. Always make small, incremental adjustments and keep track of your results to master the art of the perfect shot.