Tetsu Kasuya 4:6 Method

When Tetsu Kasuya won the 2016 World Brewers Cup, he introduced a framework so clear and adjustable that it became the default modern V60 method for serious home brewers worldwide. The 4:6 method divides the brew water into a first 40% that controls taste (sweetness vs. acidity) and a last 60% that controls strength — and crucially, it makes both dialable by changing how you split each portion, not by changing the recipe's bones. 🔢

The water is split into two phases. The first 40% (120 g for a 300 g brew) is given in two pours whose balance sets flavor: equal pours (60 g + 60 g) for balance, a smaller-then-larger split (e.g. 50 g + 70 g, or Kasuya's own 40 g + 80 g) for more sweetness, the reverse for more acidity. The last 60% (180 g) is split into more pours for a stronger cup, fewer for a milder one — typically three equal 60 g pours. Pours are spaced at a steady ~45 s interval, each begun once the bed has nearly drained, which is what lets a coarse grind extract efficiently. Kasuya sets temperature by roast: ~93°C for light, ~88°C for medium, ~83°C for dark.

#Pour Schedule

This is the balanced, sweetness-leaning version (50/70 split, then three pours):

1. 0:00 — Pour 50 g (cumulative 50 g); rest until ~0:45 (bloom).
2. 0:45 — Pour 70 g (cumulative 120 g); let it drain.
3. 1:30 — Pour 60 g (cumulative 180 g); let it drain.
4. 2:15 — Pour 60 g (cumulative 240 g); let it drain.
5. 3:00 — Pour 60 g (cumulative 300 g); let it drain.
6. ~3:30 — Remove the dripper as the last water clears.

#Why It Works

The genius is decoupling the two things drinkers care about. The early water, when the grounds are freshest and most soluble, disproportionately shapes the acid/sweet balance — so adjusting that first 40% tunes flavor. The later water, added once the bed is established, mostly adds strength — so adjusting the number of those pours tunes intensity. Letting each pour drain completely (a "pour-and-wait" rhythm) keeps the relatively coarse grind from under-extracting and yields a clean cup with minimal channeling.

The 4:6 flatters bright, light-roasted single origins where you want clarity and control. Kasuya popularized it on the Hario V60 and the Origami Dripper; the temperature and exact timings are his stated baseline and can be nudged for your beans.

#Continue Reading

• The World Brewers Cup — where the method debuted
• Hario V60 — the dripper it's built on
• The Hario Switch Hybrid Method — Kasuya's later switch approach
• The Brew Ratio — the 1:15 baseline explained
• Recipe Variables and Cup Outcomes — tuning the 40/60 splits