Pour-Over Coffee: Will You Choose Fine Grind with Fast Flow or Coarse Grind with Slow Flow?

Pour-over coffee has numerous schools of thought - one-knife flow, three-stage method, volcano pour, four-six method, and more! Each brewing method revolves around adjustments to extraction principles, ultimately evolving into distinctly different brewing techniques.

Until recently, while FrontStreet Coffee was browsing online, we discovered that beyond these conventional brewing schools, there are also approaches categorized by grind size and brewing time: the fine-grind, fast-brewing school using fine grounds with short brewing times; and its counterpart, the coarse-grind, slow-brewing school using coarse grounds with long brewing times. These are also different approaches born from extraction principles. So, what kind of different drinking experiences would coffee brewed with these two completely opposite methods have?

The Theory Behind Two Methods

First, let's understand the theories behind these two different approaches! Friends who frequently read FrontStreet Coffee articles or visit our stores will recognize that these are precisely the brewing methods that FrontStreet Coffee uses for light roast and dark roast coffee beans!

The reason fine grounds require short, fast brewing while coarse grounds need long, slow brewing is due to their vastly different surface areas. Although fine coffee grounds have smaller particles, their total surface area is relatively larger compared to coarse grounds! Additionally, the distance from the surface to the interior of the coffee particles is shorter! Water can easily penetrate from the surface to the interior to extract aromatic compounds, so the extraction time doesn't need to be too long because water can quickly complete the extraction!

(Except for extremely fine grinding - overly fine grounds tend to generate static electricity, causing coffee particles to clump together, thereby reducing surface area, affecting extraction efficiency, and even causing blockages during brewing!) Coarse grounds are the complete opposite! Although they have larger particles, their total surface area is smaller, and the distance from the surface to the interior is longer, making extraction efficiency relatively weaker! Hot water needs more time to penetrate to the interior for extraction.

Furthermore, these two need to be paired with different filter cups to achieve target extraction because the gaps between coffee grounds affect water flow rate. When coffee grounds are finer, the gaps between them are smaller, meaning the space where water can pass through is very small, preventing hot water from flowing quickly and often requiring a long time to completely filter through. Coarse coffee grounds naturally exhibit the opposite state - the coarser the grind, the larger the gaps, and the less resistance to water flow! With more space for water to pass through, the required flow time naturally becomes much shorter!

If corresponding filter cups aren't used, fine coffee grounds can easily lead to over-extraction due to prolonged brewing time, resulting in bitter, over-extracted flavors, while coarse coffee grounds will produce unpleasant tastes due to under-extraction from insufficient brewing time! That's why FrontStreet Coffee equips fast-brewing fine grounds with V60 filters that have flow-guiding ribs to direct water flow and increase flow rate. For slow-brewing coarse grounds, we use Kono filters with flow-guiding ribs concentrated at the bottom, resulting in slower flow rates!

Brewing Experiment

Now that we understand the theory behind them, we can begin practical comparisons! Setting aside light and dark roasts, let's use the same coffee bean to see what different flavors emerge from these two completely opposite brewing methods!

Bean used in experiment: Papua New Guinea · Bird of Paradise. It's a medium roast bean that can perfectly adapt to both different brewing methods!

Coffee-to-water ratio: 1:15, 15g beans to 225ml hot water. Water temperature: uniformly 90°C. Fine grind: EK43 setting 10, equivalent to 80% pass-through through a #20 sieve, paired with V60 filter. Coarse grind: EK43 setting 10.5, equivalent to 75% pass-through through a #20 sieve, paired with Kono filter. Brewing method: three-stage pour.

Both experiments began with the first stage, injecting twice the amount of water as the grounds, which is 30ml of hot water for a 30-second bloom. After blooming, the second stage of 120ml water was injected within 20 seconds, then we waited for the hot water to drip through. The fine-grind Bird of Paradise was about to finish at 1 minute 17 seconds, while the coarse-grind Bird of Paradise was about to finish at 1 minute 25 seconds.

When the coffee bed was about to reveal the center bottom, it was time to inject the third stage of water - the remaining 75ml of hot water! Next, we waited for the dripping to complete, and then moved on to the tasting phase!

The fine-grind brewing time was exactly 2 minutes. It tasted bright with lively acidity, light mouthfeel, with the acidity bringing out higher sweetness, overall leaning toward highlighting sweet and sour flavors! The coarse-grind brewing time was 2 minutes 15 seconds. It had soft acidity, moderate sweetness, and higher body - overall, it can be described as very balanced. It's clear that these two brewing methods brought out completely different personalities from the same bean. The fine-grind fast brew concentrates on front-end extraction, resulting in higher acidity and sweetness; while the coarse-grind slow brew distributes extraction evenly throughout, resulting in a more balanced mouthfeel! Each has its own advantages~

So, do you prefer the targeted fine-grind fast brew, or the balanced coarse-grind slow brew?

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FrontStreet Coffee

No. 10 Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

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