What is Tetsu Kasuya's 4:6 method and how does it work?

The 4:6 method is a V60 pour-over technique developed by Japanese barista Tetsu Kasuya, winner of the 2016 World Brewers Cup. It divides the total brew water into two groups: the first 40% (the "4") which determines acidity and sweetness balance, and the remaining 60% (the "6") which controls strength and concentration. Its power lies in its modularity — by adjusting only the number and size of pours within each group, a brewer can precisely tune the cup profile without changing grind size or brew ratio.

The 4:6 method operates on a principle of sequential, controlled extraction. In the standard recipe using 20 g of coffee and 300 ml of water at 93°C, the first 120 ml (40%) are divided into two 60 ml pours spaced 45 seconds apart. The remaining 180 ml (60%) follow in three to five equal portions, also 45 seconds apart. Total brew time targets 3:30 to 4:00 minutes.

The elegance of the system lies in the logic of each group. The first two pours — the "4" — saturate the bed and trigger extraction of organic acids and simple sugars, the most soluble compounds in coffee. By adjusting the ratio between these two initial pours, the brewer directly controls the sweet-acid balance: a smaller first pour (40 ml followed by 80 ml) increases sweetness by delaying early acid extraction; a larger first pour (80 ml followed by 40 ml) produces more brightness and acidity. The "6" pours then control final strength: fewer portions (2-3) produce a stronger, denser cup; more portions (4-5) yield a lighter, more delicate result.

Physically, the method exploits the non-linear relationship between bed saturation and hydraulic resistance. Each pour lands on a partially extracted bed, creating layered rather than simultaneous extraction — a fundamentally different mechanism from continuous-pour techniques. This reduces channeling risk because the bed is never fully submerged in one action, and the grounds have time to redistribute slightly between pours. Kasuya debuted the method at the 2016 World Brewers Cup in Dublin using a natural-processed Ethiopian coffee, winning with a cup that judges described as exceptionally clean and reproducible.

A remarkable fact: the 4:6 method is one of the very few pour-over techniques to receive its own official mobile application, developed by Kasuya himself, which calculates exact pour volumes for any custom recipe. This democratized a technique initially seen as competition-only, bringing structured pour-over methodology to home brewers worldwide.

4:6 Method — base recipe example (20 g / 300 ml)

Why a Competition Winner Changed Pour-Over Forever

Tetsu Kasuya won the 2016 World Brewers Cup with a V60 technique that seemed almost too simple to be revolutionary: divide the pour into five equal stages of 60g each, separated by waiting periods, and control the flavour profile by adjusting the split between the first two pours and the last three. His insight was that the first pours primarily extract acidity and brightness, while later pours extract sweetness and body. By making the first pour larger (say 60% of the water) you suppress acidity and build sweetness; making it smaller (40%) gives you more brightness. This framework gave brewers a systematic tool to tune flavour outcomes rather than simply adjusting grind size and temperature and hoping for the best.

What makes the 4:6 method so widely adopted in specialty cafés and home brewing is its repeatability. Unlike techniques that rely heavily on intuitive pour control or continuous stream management, the discrete staged pours of the 4:6 method produce consistent results across brewers with different hand speeds and kettles. The pauses between pours allow the bed to drain partially between each addition, which prevents the channelling that can occur in a flooded V60 bed. Japanese competition brewing culture, from which this method emerged, emphasises precision and reproducibility over improvisation — and the 4:6 method embodies that philosophy in a format accessible enough for café baristas to execute identically across dozens of daily brews.

Practical Recommendations

To apply the 4:6 method at home, use a 1:15 coffee-to-water ratio (e.g. 20g coffee, 300g water), water at 93 °C, and a medium-fine grind. Divide the water into five 60g pours, waiting 45 seconds between each. Adjust your first pour size between 40-60g to shift the flavour profile: smaller first pour for brighter, more acidic cups; larger first pour for sweeter, rounder ones. The total brew time should be around 3:30-4:00 minutes. If it runs over 4:30, grind coarser; under 3:00, grind finer. Brew the same coffee three times with different first-pour sizes side by side to discover your personal preference — this single experiment teaches more about extraction flavour levers than hours of reading.