4:6 Method

Developed by Tetsu Kasuya. 40% of the water adjusts the balance between acidity and sweetness, while the remaining 60% adjusts the strength.

Beans & Temperature

Roast level is a property of the bean, so it lives in the Bean archive — not on the brew screen. When you link a bean before brewing, the recommended water temperature is taken from its roast. Brewing manually (no bean linked) assumes a medium roast (88–90 °C).

• 1 (Very Light): 94-96°C
• 2 (Light): 91-93°C
• 3 (Medium): 88-90°C
• 4 (Dark): 84-87°C
• 5 (Very Dark): 80-84°C

Grind Size

The Grind selector records how coarsely you ground the beans, on a pour-over-centered scale:

• Coarse — French press
• Medium-coarse — Chemex
• Medium — V60 / pour-over (default)
• Medium-fine — Aeropress
• Fine — Moka / espresso

Grind is a reference and logging field — it travels with your favorites and brew log but does not change the calculated pour times. It's the lever you turn to hit those times: if a brew drains too slow, go coarser; too fast, go finer. Set a starting point under Settings → Default grind.

App Usage

1. Setup: Select your preferred ratio and choose the number of cups.
2. Profile: Use the Acidity/Sweetness slider to adjust the first two pours (40% of water). Use the Light/Strong slider to set the number of pours in the final phase (60% of water).
3. Water & Coffee: Adjust total water amount with the slider, or click directly on the Coffee/Water gram fields to type your exact amount.
4. Start: Tap 'Start Brewing'. A 3-second countdown gives you time to get ready. The configurator collapses to give full focus to the steps.
5. Follow the steps: Each step displays "Fill to X g". Pour until you reach the target, and wait for the next step. Audio cues will guide you.

Before You Brew

• Always rinse the filter. Especially important with unbleached paper, which can impart a papery taste. Pour hot water through the filter (and dripper) until the water runs clear — discard the rinse water.
• Warm up your equipment. Cold glass or thin ceramic steals 5–10 °C from your brew water during the first pours. Pour the rinse water into your cup as well, swirl and discard, then start brewing while everything is hot.
• Grind size and filter type go hand in hand. The 4:6 method aims for roughly 3.5 minutes total brew time. A fast filter (Kalita Wave, standard paper) works well with a medium-coarse grind. A slower filter (metal, thick paper, Chemex) needs a coarser grind — otherwise the brew takes too long and the coffee over-extracts and turns bitter.
  
  Quick rule of thumb: Cup finishes dripping in under 3 min → grind finer. Over 4 min → grind coarser. Don't adjust the timer — adjust the grind.

How the timing is calculated

The 4:6 method runs on a fixed ~45-second cadence — you start a new pour every 45 s regardless of amount. That cadence is the floor of every step, so a single cup follows Tetsu's rhythm exactly (≈45 s per pour, ~3 min total). The Filter nudges the floor slightly: Fast 42 s, Normal 45 s, Slow 50 s.

The last pour is different: there's no next pour to wait for, only the final drawdown, so it uses a shorter floor (~30 s). That's why a classic 5-pour single cup lands on Tetsu's 3:30 rather than a full 3:45.

A step only runs longer than its floor when a big pour needs more time to drain. Drip time is the water in that single pour divided by how fast the filter drains, and a filter drains at a roughly constant rate — so a 5–6 cup batch puts far more water in each pour and naturally stretches to 7–10 minutes. In short: step = max(floor, pour + drip). The filter therefore matters most on large batches; on a single cup the cadence dominates.

The Light/Strong slider sets how many pours make up the final 60%, which also sets the total time — more pours = stronger and longer. The classic 3:30 recipe is the 5-pour version (slider at Strong): 2 pours for the first 40%, 3 for the last 60%.

Tune how far Fast and Slow sit apart under Settings → Filter speed spread: Subtle (1.6×), Moderate (2.0×), or Strong (2.5×).

Grind size is deliberately left out of the maths. It's the lever you turn to hit these times — if a brew drains too slow or too fast, adjust the grind rather than expecting the timer to compensate.

Works Offline

MyBrew is built as a Progressive Web App. Once loaded, it works without an internet connection — useful when your phone has no signal mid-brew. You can also add it to your home screen from your browser's share menu for a full-screen, app-like experience.