“Getting the coffee grind size right makes pour-over half as hard.” For most pour-over coffee lovers, grind size is the hardest thing to control.
A reliable reference standard
Although every coffee shop has its own brewing standards, there is one standard recognized across the coffee industry: cupping! Cupping was originally designed to evaluate the quality of green coffee beans, so its extraction approach is certainly worth learning from. The grind size for cupping is a 70-75% pass rate through a #20 sieve.
[Tip: The #20 Chinese standard sieve has an aperture of 0.85 mm and is a tool for grading and testing particle sizes; any standard sieve that meets factory specifications is accurate. Calibrating your coffee grind is easy: pour the ground coffee into the sieve, cover it, shake horizontally until no more particles fall through, then weigh the particles that passed — and you will know how fine the grind is. For example, if you grind 20 g of coffee and 15.2 g passes through, the grind has a 76% pass rate on the #20 sieve. The higher the pass rate, the finer the grind.]
Since cupping grind size can be calibrated with standard sieves, the grind settings for the brewing equipment we use every day can also be clearly laid out with data.
What happens when coffee is ground too fine?
Visually, the particles are smaller, so the gaps between them are shorter, water has a harder time passing through, and drip time during brewing is longer. Finer grinding means smaller coffee particles with more surface area, giving water more places to extract coffee compounds, so concentration and extraction rate rise — the coffee tastes rich, noticeably bitter and astringent, with other flavors masked.
What happens when coffee is ground too coarse?
Visually, the particles are larger, so the gaps between them are wider, water passes through the coffee bed more easily, and filtration time during brewing is shorter. Coarser grinding means larger coffee particles with less surface area, giving water fewer places to extract, so concentration and extraction rate drop — the coffee tastes thin and hollow, light on the palate, with almost no flavor.
How to determine the grind size?
Front Street suggests calibrating like this: use 10 g of coffee beans (or a multiple of 10 for easier math — more coffee means more accurate data), pick a grind setting, grind the coffee, pour the grounds into the sieve, and shake horizontally until no significant particles keep falling (usually 3-5 minutes of shaking). Then weigh the grounds that fell through and divide by the total weight to get the pass rate. For example, if 5 g passes the sieve, the pass rate is 50%; to reach the 80% standard, adjust to a finer grind, re-grind and re-measure until you hit 80%.
Pour-over is mainly a drip method. Unlike immersion brewing, which sits long and easily pulls out unpleasant flavors, pour-over brews quickly — about 1 minute 30 seconds to 2 minutes 30 seconds. So it needs a finer grind than cupping to fully express the coffee's flavors. Also, beans of different roast levels need different grind sizes.
For medium-light roasted coffee — such as the white-floral Front Street Washed Goding, the strawberry-aroma Front Street Natural Buku Abel, and the juice-forward Front Street Kenya Cherry-Tomato — the beans are heated for a shorter time and have a harder texture, so smaller particles are needed to release more flavor; the grind is finer (75-80% pass rate);
For medium-dark roasted beans, the longer heating time makes the interior fluffy and absorbent with more caramelized compounds, so the grind should be coarser (70-75% pass rate).
Another method: watch the brew time
The fineness and uniformity of the grounds affect how fast water flows during brewing: the coarser the coffee, the faster the water drains; the finer, the slower. So when brewing a coffee without specific parameters, you can adjust the brew time by adjusting the grind.
Take Front Street Goding as an example: a pot of this light-roast coffee uses 15 g of grounds, water at 92°C, a 1:15 ratio, and takes about 2 to 2.5 minutes. If the pot finishes on time with a normal grind, you can brew directly at this grind. If the brew finishes relatively fast, the grind is too coarse and should be finer; if it takes too long, it should be coarser — adjust back and forth until the brew time falls within the normal range.
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You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
