One of the most common questions we receive from folks is “why won’t my phin filter drip?” If you’re new to the phin filter, you may experience initial troubleshooting issues when it comes to brewing a great cup of Vietnamese coffee. Worry not– we’ve got you! With a few tips and tricks, you’ll be on your way to phin brewing a bold cup of coffee without issue every time.
Grind size is key
First thing’s first: is your coffee ground for brewing with the phin filter? Grind size matters! When it comes to brewing coffee in a phin filter, it’s best to go fine– think rough grains of sand. If the ground coffee is too coarse, the water will drip right through the filter and yield an underextracted cup; too fine of a grind and the coffee may take too long to brew and overextract, create a "burnt" or unpleasant cup of coffee.
To grind coffee for the phin filter, we recommend grinding to a fineness somewhere between a pourover and an espresso. Aim for the first drop to fall before 2 minutes, and the final drop to fall around 5-6 minutes. If it's faster than this, try grinding the coffee more fine. If it's much longer than this, try grinding the coffee more coarse. Need a visual? Check out our grind guide and videos here.
A clean filter is a good filter
Prior to brewing, make sure that your phin filter is completely clean and dry (wiping it with a soft towel works great!). If there is any residual water in the holes of the filter, this can actually prevent the coffee from brewing properly. Blockage can occur with water drops or other debris if it’s not clean and dry, which can result in over-extraction and a very long brew time.
The same principle applies to the gravity press of your phin filter. Be sure that there is no blockage in the holes of both the filter chamber and the gravity press prior to adding coffee and hot water.
Too much pressure can block the flow
Let's say you've dialed in the phin with the right grind size and you started with a completely dry phin filter, but it's still not dripping? If you're using freshly ground coffee, it's possible that so much pressure has built up inside the brew chamber that it has created a suction. This is a great sign of great coffee! With freshly ground coffee, there are opposite forces happening inside the phin: the degassing of fresh coffee going up and the gravity press going down. With so much energy, it can create a suction, which then blocks water flow.
This can fixed in1 second: remove the cap, take the end of a spoon or chopstick, stick it into the water, gently lift the gravity press to release the pressure, then drop the gravity press back down. Place the cap back on and you should be back to flowing!
Not all coffee is the same
Depending on how fresh your coffee is, brew times can also vary in a phin filter. If you’re brewing freshly roasted coffee, there may be a bit of a lag when you first add hot water into the filter. We recommend covering the grounds with about an inch of water and waiting 45 seconds to allow the coffee to bloom. During this time, fresh coffee releases its gases and percolation through the filter can either begin very quickly or with a bit of a delay. After letting the coffee bloom, you should be able to add the rest of your hot water and watch the phin filter brew without issue.
Should you be brewing slightly older coffee in a phin filter, you’ll experience the opposite issue in that your coffee will most likely brew very quickly since there won’t be any blooming taking place. There’s nothing wrong with this in any way– if your coffee still refuses to drip through the phin filter, there may be an aforementioned issue with either the grind size or the holes in the filter.
Level out the coffee
One last tip we have for dialing in your phin filter brewing experience would be to level out the grounds of coffee once placed into the filter. Ground coffee can be uneven distributed even if uniformly grinded! When placing the spoons of coffee into the filter chamber, be sure to level it out by gently shaking out the filter. This ensures that there aren’t slopes in the filter which would push the hot water to one side of the filter. Additionally, shaking the filter to level the grounds also shakes out any extraneous, tiny bits of coffee that may otherwise block the holes of the filter or fall into your cup as extra sediment.
Mastering the brew
With all of these troubleshooting techniques in mind, you should be on your way to brewing a smooth, bold cup of Vietnamese coffee each and every time. Ultimately, the best way to determine whether or not it's brewing "right" is to taste the coffee! Do you like it? Do you want it more strong or more light? Remember that personalization is key! Find the right phin brew ratio for you! While it may seem intimidating at first, once you’ve dialed in your phin filter, enjoying Vietnamese coffee could not be easier or tastier!
Purchase our Phin Filter Trio here.
Read more about grind size for the phin filter and other brew methods here.