Pull & Pour's account of Tetsu Kasuya's 4:6 method divides brewing water into an initial forty percent and a remaining sixty percent. Its example uses twenty grams of coffee and five sixty-gram pours, totaling three hundred grams of water. The name describes that water division, not a coffee-to-water ratio of four to six.
The source presents changes to the early pours as a way of exploring sweetness and acidity, and changes to the later pour count as a way of exploring strength. These are useful working ideas rather than universal laws that isolate each sensory attribute perfectly. Grind, agitation, filtration and the coffee itself still interact. The supplied temperature and timing suggestions also belong to that recipe context.
When trying the framework, keep the total coffee and water clear and change only one part of the pouring pattern at a time. Record the actual result rather than assuming the intended sweetness or acidity adjustment must occur. A familiar brewer and measured inputs make that comparison more informative. The method is a structured experiment, not a promise that one schedule will produce the same preferred cup for every roast or device.
The conversation
A good question can make a better brew.