The Perfect Grind: How Fine Should Your Pour-Over Coffee Be? Your Complete Reference Guide to Coffee Grind Sizes

A delicious cup of coffee is hard to come by, since the journey from seed to cup is a very long wait. Even at the final extraction step, you must make sure the coffee you are using meets brewing standards. Extraction itself is easy, but have you ever considered that it is the coffee grounds that release the flavor compounds? The water, beans, equipment, and other elements all significantly affect the flavor of a cup.

Today we are discussing coffee grind size. This is not simple, because even grinders from the same brand are not identical. These subtle differences in grind can be enough to affect the coffee. Coffee grounds cannot simply be ground into powder the way you would make soy milk. That is why grinders have so many settings: you need to fine-tune to find the appropriate grind size, or even the best beans are meaningless.

The Importance of Grinding

Grinding relates directly to coffee extraction. The finer the grind, the higher the extraction rate; the coarser the grind, the lower the extraction rate. This involves three factors: contact time, extraction rate, and flow rate. These relationships are complementary; one inevitably affects another.

• The extraction rate of coffee grounds increases with surface area as they are ground finer.
• An increase in surface area means a finer grind, while a decrease in surface area means a coarser grind.
• The finer the coffee grind, the higher the extraction rate, resulting in shorter contact time.
• The finer the coffee grind, the slower the water flow and the longer the contact time; the coarser the coffee grind, the faster the water flow and the shorter the contact time.

This is easy to understand: espresso machines use extremely fine grounds, so espresso extraction takes only about 30 seconds; pour-over coffee uses medium-fine grounds, so contact time is around 2 minutes. When you want to use a specific brewing method, you need to set the grind size accordingly, finer or coarser. If you use extremely fine grounds to make pour-over coffee, the water flow will inevitably slow down, resulting in longer contact time and a higher extraction rate. Conversely, if you use medium-fine grounds to make espresso, the contact area is small, the water flow is fast, the extraction time is short, and the extraction rate is low.

Even if you grind at the right size for pour-over coffee, how do you verify that your grind is correct? Even a slight deviation can result in different flavors. Coffee grind size therefore needs to be adjustable, so you can achieve the best possible results.

It is worth noting that many people mistakenly believe grounds from the same grind setting are the same size. In reality, different grinders have certain assembly errors and can be calibrated regularly. You can also use standard sieves to measure the fineness of the grounds and select the appropriate grind size.

FrontStreet Coffee's grind size standard sieve pass rates are as follows:

Cold drip > Pour-over > Syphon (siphon) 80% > Mocha > American drip 75-80% > Cupping 70-75% > French press 65-70%

Choosing Grind Size

Because different grind sizes correspond to different brewing methods, adjust the coffee grind size based on the equipment you are using. Below are the grinds from finest to coarsest and their corresponding brewing methods.

1. Turkish Coffee

This belongs to the ultra-fine grind category, with a texture similar to flour. Basically, it is the smallest setting on an espresso grinder; the smaller the number, the finer the grind.

2. Espresso (as shown above)

Espresso machines use 9 atmospheres of pressure to extract coffee compounds, also belonging to the extremely fine category. However, a Turkish-level grind will clog the portafilter, preventing water flow and producing excessive extraction time. You therefore need to adjust to a coarser setting (higher number) for testing. Typically, single and double portafilters use 8-9g for single shots and 18-20g for double shots. Extracting 25-30g for single shots and 50-60g for double shots within 25-30 seconds is considered standard.

3. AeroPress (as shown below)

This is a piston-like extraction device where coffee liquid is pressed out by hand. Extraction time is about 2 minutes, but it is an immersion method, so fine grounds can lead to over-extraction. Use a grind similar to pour-over coffee but adjusted 1 to 1.5 settings coarser, falling into the medium-fine to fine category.

4. Siphon (as shown below)

Siphons use an open flame to heat boiling water, which rises from the lower chamber to the upper chamber for immersion extraction. During this process, the coffee is also stirred. Fine grinding carries the risk of over-extraction, so medium grinding is necessary.

5. Pour-over Coffee (as shown below)

This is currently the most popular brewing method, but there are still many grind variations. It is often said that you should grind to a size similar to fine sugar, but many people do not realize that even visual comparison can deviate. Pour-over coffee uses a medium-fine grind, sized between fine sugar particles. The SCA recommends a sieve pass rate of 75-80%, which defines the standard grind size for pour-over coffee.

6. Moka Pot (as shown below)

The Moka pot is an ancient coffee device that extracts coffee in the upper chamber by heating water in the bottom until it boils. Previously this was the primary method for making espresso-style coffee. The pressure is about 1.5 bar, so a relatively fine grind is needed, close to espresso grind but slightly coarser.

7. Cold Brew, Cold Drip

Both belong to long-duration, low-temperature immersion extraction, using ice water to slowly extract coffee flavors. The extraction rate of ice water is very low, so long-duration immersion requires medium-coarse grinding. Medium-coarse grinding is easier to filter and will not make the gaps between grounds too tight, which would prevent water droplets from penetrating; it also makes the coffee grounds easier to filter out.

8. French Press (as shown above)

The French press is also an immersion method, but unlike others the coffee remains immersed throughout the process. Prolonged immersion can therefore lead to over-extraction, which makes coarse grinding necessary. The grind size should be coarse, similar to larger particles like brown sugar.

The above are personal recommendations for coffee grind sizes and are for reference only. When you run into problems during actual operation, adjust immediately rather than stubbornly adhering to a specific grind size. People have different tastes: some prefer lighter coffee, others prefer stronger coffee, and this is perfectly normal. What you think is just right might seem too strong or too weak to someone else. Do not let uncontrollable factors interfere.

Currently, the most commonly used pour-over grind sizes can be calibrated with sieves, so friends who need calibration can purchase one for this purpose. Next, it is time for a brewing share. Let us brew Ethiopia Guji Buku using the standard pass rate defined by the SCA and see what surprises await.

Example: FrontStreet Coffee's Ethiopia Buku Natural

• Region: Guji, Hambela
• Variety: Heirloom
• Altitude: 1800-2000 meters
• Processing: Natural

Pour-over Parameters

• Dripper: V60
• Water Temperature: 91°C
• Grind Size: Fine sugar (standard #20 sieve pass rate 80%)
• Water-to-Coffee Ratio: 1:15
• Technique: Three-stage extraction

Brewing: Use 30g of water for a 30-second bloom. In the second stage, slowly pour in circles to 120g, and after the water level drops to halfway, pour again to 225g and stop brewing. Wait for the coffee liquid to finish dripping, then remove the dripper. Total extraction time is 2:00-2:10.

Flavor Notes

Tropical fruits, mango, strawberry, passion fruit. Full and rounded acidity with a solid mouthfeel.

FrontStreet Coffee Recommendation

Once your grind is dialed in, the beans matter just as much. For a pour-over that shows off a medium-fine grind, FrontStreet Coffee's Ethiopia Huakui is a natural processed coffee full of strawberry, passion fruit, jackfruit, citrus, and blueberry aromas, with a smooth, juicy body and very low bitterness. FrontStreet Coffee's Yirgacheffe Gedingding is a G1 washed lot with jasmine, citrus, and green tea notes that stays clean and bright on a medium-fine grind.

If you prefer a tea-like, floral cup, FrontStreet Coffee's Strawberry Candy combines Costa Rican honey processing with Panama Geisha for dried grape, orange, and ripe blueberry notes with a rose-like fragrance and an almond finish. For a fuller, more traditional profile, FrontStreet Coffee's Indonesia Golden Mandheling is a wet-hulled Sumatran coffee with low acidity, a thick body, and herbal and dark chocolate notes.

For brewing, FrontStreet Coffee suggests a V60 at 91°C, 15g of coffee at a 1:15 ratio, and a medium-fine grind at about 80% pass-through on a #20 sieve, which is the standard pour-over grind size described above.