How to use a phin filter: a step-by-step guide

To use a phin filter, set it on a cup, add about 2 tablespoons of coarse-medium ground coffee, place the insert on top, pour in a little hot water to let the grounds bloom, then fill it and wait about 4 to 5 minutes while the coffee drips through. The tricky part is getting the drip speed right, and that comes down to grind size and how firmly the insert sits.

This guide focuses on the phin itself: its parts, the different types and how to troubleshoot. If you just want a quick recipe, see how to make Vietnamese coffee at home.

What are the parts of a phin?

Most phins have four pieces:

• Base plate: a flat, perforated disc with a rim that sits on the cup. It catches drips and holds the chamber.
• Brew chamber: the cup-shaped body with small holes in the bottom where the coffee goes.
• Filter press (insert): a perforated disc that sits on top of the grounds. It keeps them from floating and controls how fast water passes through.
• Lid: keeps heat in while brewing, then doubles as a drip tray when you lift the phin off.

On some phins, the base plate and chamber are one piece.

Gravity insert vs screw-down insert

There are two common insert styles:

• Gravity (press-fit) insert: just rests on the grounds. You press it gently by hand, and it stays in place by friction and weight. Common on newer phins.
• Screw-down insert: has a center screw you turn to tighten it against the grounds. It offers more control but is easier to over-tighten, which can stop the drip.

With a screw-down insert, tighten it gently and then back it off about a half turn after the bloom if the coffee isn't dripping.

Aluminum vs stainless steel

• Aluminum: the classic, cheap and lightweight. It can dent and may discolor over time.
• Stainless steel: more durable and easier to keep looking clean, usually a bit pricier.

Either works fine. Size matters more: 4 oz, 6 oz and 8 oz versions exist, and a 6 oz or 8 oz phin is easiest for most mugs and glasses.

What grind should you use?

Aim for coarse-medium, a little coarser than typical drip-machine grind but finer than French press. Many Vietnamese coffee brands are already ground for phin brewing. If you grind your own, start coarser and adjust finer if the drip runs too fast.

The brew ratio

A standard starting point:

• About 2 tablespoons (15 to 20 g) of ground coffee
• About 1/2 cup (120 ml) of hot water, just off the boil

That makes a small, strong cup, around 3 to 4 oz (90 to 120 ml) after the grounds absorb some water.

Step by step

1. Preheat. Pour hot water through the empty phin into your cup. Discard it.

2. Add coffee. Put the chamber on the cup and add the grounds. Tap or shake gently to level them.

3. Seat the insert. Place the insert on the grounds and press lightly. Don't pack it hard.

4. Bloom. Add about 2 tablespoons (30 ml) of hot water. Wait 30 to 45 seconds for the grounds to swell.

5. Fill. Fill the chamber to the top and cover with the lid.

6. Watch the drip. Aim for a steady drip of about one or two drops per second, finishing in 4 to 5 minutes.

7. Finish. Lift the phin and rest it on the upturned lid. Add condensed milk, sugar or ice as you like.

Troubleshooting

• Nothing drips: the insert is too tight or the grind is too fine. Loosen the insert, or lift it slightly with a spoon.
• Runs through in a minute: too coarse, or the insert is too loose. Grind finer, add a bit more coffee or press the insert more firmly.
• Sludge in the cup: grind too fine for your phin's holes. Go coarser.
• Weak coffee: not enough coffee or a drip that's too fast. Increase the dose.
• Bitter, harsh coffee: drip too slow. Loosen the insert or grind coarser.
• Insert floats up: you added water too quickly. Pour gently, and press the insert back down after the bloom.

Cleaning and care

Knock out the used grounds (they make good compost) and rinse every part with hot water. Let it air dry. If the holes clog, soak the parts in hot water and use a soft brush. Avoid harsh scrubbers on aluminum.

Does a phin work for decaf or other coffees?

Yes. A phin works with any coffee ground to the right size. Lighter arabica roasts taste brighter and less intense, while dark robusta gives the classic Vietnamese flavor. For a full explanation of the beans, see robusta vs arabica, and for iced drinks, try cà phê sữa đá.

Change only one thing at a time, grind, dose or insert pressure, so you know what fixed the drip.