Brew time is the cheapest diagnostic in coffee. It costs nothing to measure, it responds immediately to grind changes, and it narrows the cause of a bad cup faster than taste alone. What it cannot do is tell you the coffee is good — a shot can hit 27 seconds and still taste wrong.
Target times by method
These are starting points for a given grind, not deadlines. A grinder that produces more fines runs slower at any setting, so the absolute number matters less than consistency: the same method, dose and ratio should give the same time within a few seconds every day.
| Method | Dose | Target time | Grind | Water |
|---|---|---|---|---|
| Espresso | 18 g | 25–30 s | Fine | — |
| Moka pot | 15 g | 3–5 min | Fine-medium | 150 g |
| AeroPress | 15 g | 1:30–2:00 | Medium-fine | 200 g |
| V60 | 15 g | 2:30–3:30 | Medium-fine | 225–250 g |
| Chemex | 30 g | 4:00–5:00 | Medium | 480–500 g |
| French press | 30 g | 4:00 + 0:30 press | Coarse | 480 g |
| Cold brew | 100 g | 12–18 h | Coarse | 800 g |
The four-quadrant diagnostic
Time alone is ambiguous — fast can mean too coarse or it can mean channelling, and those need opposite fixes. Pair time with taste and the ambiguity collapses.
Read the row that matches your result, then check the taste. This table resolves most dialling problems in one shot instead of five.
| Time | Taste | Cause | Fix |
|---|---|---|---|
| Faster than target | Sour, thin | Grind too coarse | Grind finer |
| Faster than target | Bitter, harsh | Channelling | Fix pour and distribution |
| Slower than target | Bitter, dry | Grind too fine, or too many fines | Grind coarser |
| Slower than target | Sour, hollow | Bypass, water not reaching the bed | Stir, check filter seal |
| On target | Balanced | — | Change nothing |
How dose changes time
Immersion brewers scale almost linearly — doubling the coffee roughly doubles the steep time needed for equal extraction. Pour over is worse than linear, because a deeper bed resists flow and the water spends longer above the surface before it drains.
Going from 15 g to 30 g on a V60 typically adds 60 to 90 seconds, and usually needs a slightly coarser grind on top of that. If you scale a recipe up and do not touch the grind, you get a stalled brew that tastes simultaneously sour and bitter, which is confusing until you recognise it as channelling through an over-deep bed.
Why time is a proxy, not a measurement
Two cups can finish in exactly three minutes and extract completely differently. Extraction depends on flow resistance, temperature, water chemistry, particle distribution, and the coffee itself. Time measures only flow resistance.
Use time to decide which direction to move the grinder. Use taste to decide whether you got there. If you only use time you will eventually produce a perfectly timed, mediocre cup and stop noticing.
The one number to track daily
If you log anything, log total brew time at fixed dose and ratio. It drifts as beans age — typically 1 to 2 seconds faster per day on espresso as the beans degas — and that drift is the signal to grind finer, often before you can taste the change. A written log turns a vague feeling that the coffee got worse into a concrete adjustment.