Very fine — like powdered sugar or fine sand. The coffee grounds should feel slightly sticky between your fingers. Rule of thumb: 18 g should extract into 36 g of espresso in 25–30 seconds.

What grind size do I need for espresso?

Very fine — like powdered sugar or fine sand. The coffee grounds should feel slightly sticky between your fingers. Rule of thumb: 18 g should extract into 36 g of espresso in 25–30 seconds.

Why this is the case

Espresso is a high-pressure extraction method. The machine forces hot water at 9 bars of pressure through a compacted cake of coffee grounds — known as the puck. To prevent the water from just shooting straight through, the grind size must be fine enough to offer resistance. At the same time, it can’t be so fine that the water can’t get through at all.

The ideal grind size for espresso is finer than for almost any other brewing method. It sits somewhere between powdered sugar and fine sand. If you rub the coffee grounds between your thumb and index finger, they should feel slightly sticky and clump together. If it trickles through your fingers like loose sand, it’s too coarse for espresso.

The exact setting depends entirely on the grinder — every grinder has its own scale. Instead of looking for a universal number, you should guide yourself by the result in the cup: 18 g of ground coffee in the portafilter basket, yielding 36 g of espresso, with a shot time of 25–30 seconds. This results in a 1:2 ratio and a well-balanced extraction.

If the espresso flows too quickly (under 20 seconds), the grind is too coarse — the result will taste watery and sour. If it flows too slowly (over 35 seconds), the grind is too fine — the espresso will be bitter and over-extracted. In both scenarios, adjust the grind size in small increments. Dedicated espresso grinders feature stepless adjustments because just a millimeter of movement can make all the difference.

Important note: The optimal grind size is not static. Fresher beans generally require a slightly coarser grind than older ones because they contain more CO₂, which slows down the water flow. Humidity and room temperature also play a role. Professional baristas recalibrate their grind sizes several times throughout the day.

In practice at Green Wall Coffee

In our café at Sophienstraße 27, I dial in the grind size with the first shot of the morning and continue to check it throughout the day. If the weather changes significantly or we open a new batch of beans, the setting might need adjustment. For guests making espresso at home, my advice is: invest in a grinder with fine adjustability. Cheap grinders with stepped settings often miss the exact sweet spot for espresso — and that makes the difference between an okay shot and a great one.

Related questions

• Why should you grind coffee fresh?
• What grind size do I need for filter coffee?
• Which is better: flat burr or conical burr grinder?

For more depth on the subject, check out our article on how to make perfect espresso. Or visit us at Sophienstraße 27 — Mon–Fri 8am–5pm, Sat 10am–5pm.