4:6 method calculator.
Kasuya's method gives you two independent dials: the first 40% of the water sets sweetness against acidity, the last 60% sets strength. Set both, scale to your dose, and every pour comes out weighed and timed.
How to use the two dials
The whole point of the method is that these two controls do not interfere with each other. Change one, brew, taste, then change the other — never both.
The first 40% — sweetness against acidity
The first two pours always add up to 40% of your total water. What you change is how that total is split between them. A smaller first pour gives more sweetness. A larger first pour gives more acidity and clarity. On a washed Ethiopian that is already screaming bright, go smaller. On a flat-tasting washed Brazil, go larger.
The last 60% — strength
The remaining 60% is fixed in total and split into one, two or three pours. More pours means more agitation and more contact with fresh water, so more extraction and a fuller body. One single pour gives the lightest, most tea-like cup. Kasuya's own competition setting is three.
Grind coarser than you think
Five or six separate pours add up to a long total brew time, and a normal V60 grind will over-extract badly by the end. This recipe wants a noticeably coarser grind than your usual pour-over setting — that is what buys back the time. If the bed is stalling between pours or you are finishing well past 3:30, coarsen further before changing anything else.
Your grinder's specific number for this is on its grind chart — start a step or two coarser than the V60 row.
Pour technique
- Each pour should take roughly ten seconds. Dumping the water in floods the bed and destroys the control the method is built on.
- Let the bed draw down between pours. If it has not cleared when the next pour is due, the grind is too fine for this recipe.
- Pour in circles, keep the grounds off the paper walls, and give a gentle swirl at the end of the last pour to settle the bed flat.
- Water at 92–93 °C. Kasuya's original brews hot.
Coffee Aeye runs this as a guided brew-along: a full-screen timer with the progress ring, each pour's target weight counted down, and audio cues so your hands stay on the kettle. Connect a Bookoo Themis or Felicita Arc and it shows live weight and flow against each target as you pour. Get it on Google Play — €4.29, one-time.
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