How Does Grind Size Affect Coffee Extraction in Pour-Over?
Grind size controls how quickly flavor compounds dissolve during pour-over brewing. Brewing a naturally processed Ethiopian Sidamo Candle Light at three settings with the same dose, water temperature, and ratio showed that the finest grind, BG-5I, tasted bitter and muddled, while the middle grind, BG-5T, gave a full body with citrus, mango, nectarine, and a sweet finish.
The coarsest grind, BG-7D, ran at 43 percent passing on the No. 20 sieve. All brews used 15 grams of coffee at 1:15 with 90 degree water and staged pours. A coffee enthusiast can use these results to adjust grind, since extraction time and flavor shift together, and different roast levels call for adapted water temperatures.
Grind size is one of the key variables affecting extraction results in pour-over coffee, directly relating to the dissolution efficiency of flavor compounds and the balance of the final cup. This article takes a naturally processed Ethiopian Sidamo Candle Light as an example, using three different grind sizes—BG-5I, BG-5T, and BG-7D—to conduct brewing comparisons under identical conditions of coffee dose, water temperature, and coffee-to-water ratio, recording the flavor differences under each grind size through actual tasting. The article not only presents complete brewing parameters and flavor descriptions but also shares knowledge about the principles of staged extraction and water temperature adaptation for different roast levels, making it a useful reference for coffee enthusiasts looking to refine their pour-over technique.
Sidamo Candle Light
Region: Sidamo, Ethiopia
Altitude: 1,750–2,000 meters
Processing method: Natural
Variety: Local heirloom
Roast level: Light roast
Flavor: Citrus, mango, nectarine, tropical fruits
Grind size BG-5I ( ( 75% passing rate on Chinese standard No. 20 sieve)
Parameters: 15g coffee; water temperature 90℃; coffee-to-water ratio 1:15; brewing method: staged extraction. Bloom with 35g water for 30 seconds, pour to 132g for the first stage, continue pouring to 226g when the water level is about to expose the coffee bed, then remove the dripper when the water level is about to expose the coffee bed again (timing starts from the beginning of the bloom). Total extraction time: 2'07"
Flavor: Fermented aroma, citrus, mango, nectarine; overall quite bitter, intense, and muddled, with a prominent bitter aftertaste.
Grind size BG-5T( ( 58% passing rate on Chinese standard No. 20 sieve)
Parameters: 15g coffee; water temperature 90℃; coffee-to-water ratio 1:15; brewing method: staged extraction. Bloom with 32g water for 30 seconds, pour to 125g for the first stage, continue pouring to 227g when the water level is about to expose the coffee bed, then remove the dripper when the water level is about to expose the coffee bed again (timing starts from the beginning of the bloom). Total extraction time: 1'56".
Flavor: Citrus, mango, nectarine, cream; creamy aroma in the finish with a hint of nuts; overall quite full-bodied with a notably sweet aftertaste.
Grind size BG-7D( ( 43% passing rate on Chinese standard No. 20 sieve)
Parameters: 15g coffee; water temperature 90℃; coffee-to-water ratio 1:15; brewing method: staged extraction. Bloom with 34g water for 30 seconds, pour to 132g for the first stage, continue pouring to 225g when the water level is about to expose the coffee bed, then remove the dripper when the water level is about to expose the coffee bed again (timing starts from the beginning of the bloom). Total extraction time: 1'53".
Flavor: Tropical fruits, honey, cream; a faint fermented aroma in the finish; overall relatively thin-bodied, lacking the fullness typical of natural processing.
Through these three brews, the grind size BG-5I (75% passing rate on Chinese standard No. 20 sieve)—slightly finer than medium-fine—produced a cup where the bitterness noticeably masked the tropical fruit flavors inherent to this Sidamo Candle Light; the grind size BG-5T (58% passing rate on Chinese standard No. 20 sieve) allowed the coffee to express the bean's flavors as a whole, and this is the grind size the author typically uses, mainly because its particle distribution is relatively uniform, avoiding inconsistency in extraction and allowing the dissolution of coffee flavors to reach a relatively saturated state. Of course, this grind size is also the result of continuous calibration with a sieve and repeated brewing trials; slightly coarser than medium-fine, the grind size BG-7D (43% passing rate on Chinese standard No. 20 sieve) produced a cup that was noticeably under-extracted, with a somewhat thin overall body and a lacking finish.
Finally, let's share some pour-over tips~
① Regarding coffee extraction, in general, the early stage of extraction yields intense aroma and flavor with high concentration; the further along, the more the flavor and aroma diminish. In other words, the early stage of extraction dissolves the maximum amount of coffee compounds, thus playing a decisive role in the coffee's taste and aroma. What dissolves in the later stage of extraction are the woody components that form the structure of the coffee bean; this part contributes more to body and bitterness, which is also why we sometimes gently increase the flow rate in the later stage for even extraction.
② Regarding water temperature, for light-to-medium roast beans, 90–92℃ is more suitable. If the temperature is higher than this, some compounds in the coffee will change due to the higher water temperature, typically manifesting as pronounced bitterness with some burnt notes; for medium-dark beans, the temperature should be 88–85℃. Dark-roasted beans, due to the severe damage to cell walls during roasting, have a relatively loose texture and absorb water well. The coffee bed expands easily when exposed to water. If extracted above this temperature, the coffee will be quite intense and over-extracted, with astringency.
The above content is compiled by CoffeeHunters, a coffee news website.
