Vietnamese Phin Coffee Ratio

A phin brews at roughly 1:10 — 1:12 for a lighter pour, 1:8 for a stronger one — using a small metal filter that sits directly on top of the cup and drips by gravity alone, no paper, no plunger, no pump. The ratio here describes the black coffee only; the sweetened condensed milk traditionally layered into the glass beforehand for cà phê sữa đá is a separate measurement that doesn't factor into this page's numbers at all.

How the filter actually works

A phin has a perforated metal disc that sits inside a small cup-shaped chamber, with a second disc or a press-fit lid on top to keep the grounds compressed and in place. Hot water is poured over the grounds and finds its own way down through the compressed bed and the bottom disc's holes, dripping slowly into the glass below over several minutes with no pouring technique or agitation involved once the water's been added — closer in spirit to a very slow, gravity-only pour-over than to anything requiring active attention during the drip itself.

Working the numbers at a single-serving dose

At 1:10, a 15g dose calls for about 150ml of water. At 1:8, 120ml, for the stronger, more traditional cup phin coffee is known for. At 1:12, 180ml, for something a little more diluted. Phins are almost always sized for one serving; making more means using a second phin or brewing in sequence, not scaling one phin's dose up the way you'd scale a French press.

Why the grind and the ratio are both non-negotiable together

A medium-coarse grind is what lets the phin drip at a reasonable pace without water finding its way through instantly or stalling entirely — because there's no mechanism for controlling flow beyond the grind itself and how tightly the press-fit disc is seated, getting the grind slightly wrong changes contact time far more directly here than in a method with an adjustable pour or plunge. If a phin drains in under two minutes, the grind is too coarse for that ratio to extract properly; well past five or six minutes, it's too fine.

The milk question, separately

Traditional cà phê sữa đá layers two to three tablespoons of sweetened condensed milk in the bottom of the glass, with the black coffee from the phin dripping directly on top before stirring and pouring over ice. That milk quantity is a matter of personal sweetness preference, adjusted independently of the coffee-to-water ratio above — a stronger 1:8 brew holds up better against a generous pour of milk, while a lighter 1:12 brew can get lost under too much of it.

Moving between strengths

Reach for 1:8 for the traditional intensity that stands up to condensed milk and ice. Reach for 1:12 if drinking it black, unsweetened, and want something gentler. If the drip stalls or floods rather than the strength being off, that's the grind, not the ratio.

Pre-wetting the grounds changes the whole drip

Many phin recipes call for a small splash of hot water poured over the grounds first, left to sit for perhaps 30 seconds before the rest of the water is added — similar in spirit to a pour-over bloom, letting trapped gas escape before the main pour so the drip runs more evenly rather than sputtering unevenly through the disc. Skipping this step is a common reason two people using the same ratio and grind get noticeably different results from the same phin.

For assembly, press technique, and how phin coffee compares to Turkish coffee's very different, filter-free approach, see the full Vietnamese phin guide.