Understanding Coffee Grind Sizes: A Visual Guide to Grind Differences for Moka Pots and Pour-Over Coffee

What grind size should I use for pour-over coffee?

"Excuse me, what's the grind size for pour-over coffee?", "Why does the 10-mark grind on your machine differ from the 10-mark on my machine?", "Is sugar-sized grind referring to fine sugar, coarse sugar, or brown sugar?"... Are you still struggling to find the right grind size for your coffee brewing equipment? FrontStreet Coffee's article will help you determine the perfect coffee grind fineness! (Save! Save! Save it now!!)

How Important is Coffee Grind Size?

With the same amount of coffee beans, the finer the grind, the more cuts are needed, increasing the surface area. This allows water to contact more of the coffee grounds. Conversely, coarser grinds result in lower coffee concentration and extraction rate, less body, and stronger acidity.

Different coffee brewing equipment requires different grind sizes due to their varying extraction methods. Additionally, coffee grinder markings are not standardized across different machines. Therefore, we need a reliable testing tool—the China Standard No. 20 0.85mm aperture sieve/coffee bean grind cup calibration sieve, which FrontStreet Coffee commonly refers to as the coffee grounds sieve.

How to Use a Coffee Sieve to Determine Grind Size?

Careful readers might ask: Why use a cupping calibration sieve? Although there are various brewing methods on the market with different parameters, cupping is the recognized testing standard in the coffee industry. Initially, cupping was used to evaluate green bean quality, but gradually, people also began using cupping to determine coffee flavors before deciding on suitable brewing parameters. The grind size for cupping is 70-75% pass-through rate on a No. 20 sieve.

The usage method is quite simple: When FrontStreet Coffee determines grind size, we use 10g of coffee beans for an initial grind, then pour it into the middle layer of the sieve, cover with the lid, and shake horizontally until no coffee particles fall into the lower collection bowl. Then weigh the coffee particles that passed through the sieve—the resulting weight is the pass-through rate. If 7-7.5g of 10g coffee passes through the sieve, then this grind size has a 70-75% pass-through rate on a No. 20 sieve. The finer the coffee particles, the higher the pass-through rate; the coarser the coffee particles, the lower the pass-through rate.

Common Brewing Equipment Grind Size Standards & Reference Images

Drip Extraction/Pour-over Coffee Grind Size (No. 20 sieve pass-through rate: 68-80%)

Suitable for: V60, Kono, KASUYA, Origami, conical filters, flat-bottom filters, Clever Dripper, American drip coffee makers

Drip brewing or pour-over coffee works on the principle where water extracts substances from coffee grounds and then filters through paper to produce clean coffee liquid. Generally, pour-over coffee has a shorter brewing time, so a finer grind size is needed.

Different roast levels of coffee beans require different grind sizes. FrontStreet Coffee suggests a grind size of 75-80% pass-through rate on No. 20 sieve for light to medium roast beans; and 70-75% pass-through rate for medium-dark roast beans.

Immersion Extraction/French Press Grind Size (No. 20 sieve pass-through rate: 68-75%)

French press uses immersion for coffee extraction, with longer immersion times (4 minutes), and its filter has larger mesh, so a coarser grind size is needed. This reduces over-extraction and better filters coffee particles.

Different roast levels of coffee beans require different grind sizes. FrontStreet Coffee suggests a grind size of 70-75% pass-through rate on No. 20 sieve for light to medium roast beans; and 65-70% pass-through rate for medium-dark roast beans.

Cold Extraction/Cold Brew, Ice Drip Coffee Grind Size (No. 20 sieve pass-through rate: 80-85%)

Cold extraction differs from hot extraction. In ice water mixtures or refrigerated environments, coffee extraction efficiency is very low, so the release rate of flavor compounds from coffee grounds also slows down, making the production time quite lengthy. The advantage of cold extraction is that it can fully extract sweet and sour compounds while reducing the extraction of bitter compounds.

Due to slow extraction speed, coffee grind size can be finer, but not too fine. FrontStreet Coffee recommends a grind size of 80-85% pass-through rate on No. 20 sieve for making cold brew/ice drip coffee. If you prefer stronger flavor, choose 85% pass-through rate; for a cleaner taste, choose 80% pass-through rate.

Pressurized Extraction/Espresso Machine Grind Size (Cannot be determined with No. 20 sieve)

The grind size used in espresso machines is very fine, finer than 0.85mm aperture, so it cannot be determined using a No. 20 sieve. As for how fine it is, we can refer to the image below.

To determine the grind size for espresso, you need to continuously extract and taste to adjust the grind. FrontStreet Coffee's espresso extraction recipe is 20g of coffee grounds to extract 40g of espresso liquid in 28 seconds (with ±1 second tolerance). You can refer to this extraction recipe and make fine adjustments based on the flavor performance of the espresso.

Steam Pressure Extraction/Moka Pot Coffee Grind Size (Cannot be determined with No. 20 sieve)

The Moka pot is similar—it uses a very fine grind, but slightly coarser than espresso machine grind. However, it's still finer than 0.85mm aperture, so it cannot be determined using a No. 20 sieve.

As for the grind size, you can refer to the gap size in the Moka pot's coffee basket, ensuring coffee particles don't pass through the gap. You can refer to the image below.

- Great! You've learned another useful piece of coffee knowledge -

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