I brew pour-over coffee most mornings, and for the past year or so I've been using the 4:6 method — the brewing technique that Tetsu Kasuya used to win the 2016 World Brewers Cup.
If you haven't tried it: you split your total water into 40% and 60%. The first 40% goes in as two pours and controls the taste (a bigger first pour skews bright/acidic, a smaller one skews sweet). The remaining 60% controls the strength — more pours means a stronger cup. Every pour lands on a 45-second interval. It's simple, repeatable, and it genuinely changed how my coffee tastes.
The problem: coffee math at 7am
The standard recipe (20g beans, 300g water, five 60g pours) is easy to memorize. But the moment you deviate — 17g of beans left in the bag, or brewing for two people — you're standing there with a kettle in one hand doing arithmetic: 17 × 15 = 255g total, 40% of that is 102g split into two pours, and I want it sweeter so the first pour should be smaller than the second…
Meanwhile your timer is a separate app, and your phone screen just went to sleep.
There are plenty of articles explaining the 4:6 method. What I couldn't find was a tool that does the calculation and walks you through the pours in one place. So I built one.
What I built
Coffee Extraction Ratio & 4:6 Method Timer — free, runs entirely in the browser:
Three steps:
- Enter your bean amount (defaults to 20g). Pick a ratio — 1:15 to 1:18 presets or a custom value
- Choose taste and strength. Taste (bright / balanced / sweet) adjusts how the first 40% is split between two pours; strength (light / standard / strong) sets whether the last 60% is 1, 2, or 3 pours
- Hit Start Timer
The tool generates the full pouring schedule — per-pour amount, cumulative weight, and timing — and then beeps (and vibrates on mobile) every 45 seconds to cue the next pour. Your scale's cumulative reading just has to match the number on screen. No thinking required mid-brew.
The default "strong" setting reproduces Kasuya's classic 60g × 5 pours recipe, so that's a good starting point if you're new to the method.
The nerdy bits
Since this is DEV, a few implementation notes:
- It's part of a small utilities site built with Astro — fully static, with each tool as a client-side React island. No backend, no accounts, nothing you type ever leaves the browser
- Wake Lock API keeps the screen on during the brew. A timer you can't see because your phone went to sleep is useless, and this turned out to be the feature I appreciate most at 7am
- Pour cues use a simple audio beep plus the Vibration API on mobile, so you get the cue even with the sound off
- There's also a reverse mode: enter the water you have and it calculates the beans you need
Try it
If you're into pour-over — or you've been meaning to try the 4:6 method — give it a spin. It works best saved to your phone's home screen, set up while the kettle heats.
Feedback and feature ideas are very welcome in the comments.
It's part of a small collection of free browser tools I'm building: Utilities Web
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