You finally got one great cup out of your phin. Strong, smooth, not a trace of sourness. The next morning you did "the same thing" — and it ran through in ninety seconds. Sound familiar? Learning curve is the word people use most when they talk about Vietnamese coffee at home, and most of it comes from guessing. A small kitchen scale with a timer turns the guessing into two numbers you can repeat.
Why measure a phin at all?
A phin is a gravity brewer. How fast the water passes through depends on how much coffee is in the chamber, how fine it is ground, and how the press sits. Tablespoons are a rough guide: a level spoon of fine coffee and a heaped spoon of coarse coffee can differ a lot in weight. When you weigh the dose and time the drip, you can change one thing at a time and actually see what happened.
The two numbers that matter
- Dose: start around 20 g of medium-coarse coffee for a standard phin (roughly 2–3 tablespoons).
- Drip time: aim for about 4–6 minutes from filling the chamber to the last drop, after a short bloom.
Those are starting points, not rules. Your coffee, your grinder and your phin will move them a little. The point is to write them down.
Step by step: weigh and time one cup
- Put your cup and phin on the scale, then press tare. The display goes back to zero, so you only weigh the coffee.
- Add coffee until the display reads about 20 g. Shake the chamber gently to level the bed, then set the press on top without packing it hard.
- Tare again and bloom. Pour just enough hot water to wet the grounds (about 20 g of water), then wait 30–45 seconds.
- Start the timer yourself as you fill the chamber. Fill slowly, put the lid on, and let it drip.
- Stop the timer at the last drop and note the time next to the dose.
Use the timer manually
Many coffee scales start the timer automatically when they sense water. That works for fast pour-over, but a phin drips slowly and the first bloom can confuse auto-start. For a phin, start and stop the timer by hand: one press when you fill the chamber, one press at the last drop. You get a clean number every time.
Read the result, then change one thing
- Under 3 minutes, thin or sour: grind a step finer, or add 2–3 g more coffee.
- 4–6 minutes, strong and smooth: keep it. Write it down.
- Over 8 minutes, bitter or stalled: grind a step coarser, or use a little less coffee.
Change only one dial per cup. After three or four mornings you will know your phin by heart. For the full list of fixes, read Why Is My Phin Dripping Too Fast? 7 Easy Fixes.
Small habits that keep your readings honest
- Set the scale on a flat, dry counter, and tare with everything already on it.
- Keep water off the underside of the scale; wipe spills right away.
- Charge it before the battery runs low, so the display does not dim mid-brew.
- If a reading seems off, check it with something of known weight, like a coin roll or a full unopened package with a printed net weight.
Quick cheat sheet
Tare → 20 g coffee → level, set the press → tare → 20 g water bloom, 30–45 s → start timer, fill slowly → stop at last drop → aim for 4–6 minutes.
Want the whole routine on paper, plus 12 recipes? Get the free Phin Guide, or see our how to brew with a phin page. The scale we use is the Drip-Timer Coffee Scale: it weighs and times on one backlit display.
We sell the gear, not the coffee. Brewing tools only — coffee not included.