Introduction:Grind size is one of the core factors influencing the flavor of pour over coffee, but the lack of a unified standard for grind settings on commercial grinders often leaves beginners at a loss. This article uses the Chinese Standard No. 20 sieve with a 0.85mm aperture to teach you how to accurately measure coffee ground passing rates, and provides practical grind reference ranges for common brewing methods such as pour over, French press, and cold brew, under different roast levels—so you can easily adjust to your ideal extraction parameters.
Grind size not only determines the strength and flavor release of coffee, but is also key to extraction uniformity. However, the grind setting markings on different grinders vary greatly—even if the numbers are the same, the actual particle sizes can differ significantly. To solve this issue,Chinese Standard No. 20 sieve with 0.85mm aperture(also known as a coffee ground sieve) is the most reliable quantitative tool, helping you objectively assess the fineness of your coffee grounds.
This sieve originates from the coffee cupping field, where the industry commonly adopts a 70–75% passing rate as a standard reference value. The operation is simple: take 10 grams of coffee beans, grind them, then pour the powder into the sieve and gently shake until no more particles fall through. Finally, weigh the coffee grounds that passed through the sieve. If the passing amount falls within the range of 7 to 7.5 grams, it means the grind size meets the 70–75% passing rate standard of the No. 20 sieve. The finer the particles, the higher the percentage passing through the sieve; the coarser, the lower.
Different brewing methods have vastly different grind size requirements. Taking the most common pour over method as an example, its principle is to let hot water pass through a bed of coffee grounds, extracting flavor compounds which are then filtered through paper. Since the brewing time is relatively short, a finer grind size is generally recommended, with the overall range falling between 68–80% passing rate for the No. 20 sieve. Specifically,medium-light to medium roasted beans suit a 75–80% passing rate, bringing out richer fruit acids and aromas; whilemedium-dark roasted beans are recommended to use a 70–75% passing rate, to avoid over-extraction that can lead to bitterness.
The French press, on the other hand, uses a completely different immersion-style extraction, with a soaking time of about 4 minutes and a relatively dense filter, requiring a coarser grind size to prevent over-extraction. It is suggested thatmedium-light to medium roasted beans use a 70–75% passing rate,while medium-dark roasted beans should be adjusted to a 65–70% passing rate, ensuring sufficient extraction while effectively filtering out coffee grounds through the mesh.
For low-temperature extractions such as cold brew or ice drip coffee, due to the low extraction temperature and slow process, a slightly finer grind size is recommended to enhance the efficiency of flavor compound release. A passing rate of 80–85% using the No. 20 sieve is advised; if you prefer a richer taste, choose 85%, while for a crisper flavor, aim for 80%.
As for espresso machines and moka pots, because they require high-pressure extraction, the grind size is much finer than the 0.85mm aperture and cannot be measured using the No. 20 sieve. For espresso, it is recommended to adjust based on the benchmark of extracting 40 grams of coffee liquid in 28 seconds with 20 grams of coffee grounds; for the moka pot, you can observe the coffee grounds in the filter basket to ensure no leakage occurs—the actual fineness should be fine-tuned according to the specific characteristics of the device.
The above content is compiled by CoffeeHunters, a coffee news website.
