guides · brewing
how to brew a drip coffee bag well
by toshi · updated 14.08.26
A drip bag makes a good cup with no special knowledge. This page shows the standard procedure and the corrections for the usual problems. The numbers come from published brew research and from our own tests. If the format is new to you, start with what is a coffee drip bag.
the procedure
- Tear the packet open.
- Unfold the 2 paper ears.
- Put the ears on the rim of your mug.
- Boil the water, then let it stay off the heat for 30 seconds.
- Pour a small quantity of water on the grounds, until they are wet.
- Wait 30 seconds. This step is the bloom.
- Pour the remaining water slowly, in 2 or 3 steps, to a total of approximately 200 ml.
- Keep the water level below the top edge of the paper.
- When the flow stops, lift the filter out of the mug.
- Discard the filter. The filter material goes in the compost.
The total time is approximately 2 minutes.
why the bloom
Roasted coffee contains carbon dioxide from the roast. The gas comes out of the coffee for days, and more quickly after the grind.SCA review When water touches the grounds, the gas comes out fast and pushes the water away. The 30-second bloom lets the gas out first. Then the water can touch all the grounds equally, and the extraction is even.
the ratio, and the standard
The toshi ratio is 12 g of coffee to 200 ml of water, or 60 g for each liter. This is in the Golden Cup range of the Specialty Coffee Association, the industry standard for filter coffee.
The 12 g to 200 ml ratio is set to put the cup in the golden cup zone.
golden cup zone · 18 to 22% extraction
The zone is the industry standard for filter coffee, 18 to 22% of the coffee mass in the water. No measurement tools are necessary at the correct ratio. SCA golden cup standard
problems and corrections
the cup is weak
Use less water, or pour more slowly. The standard ratio is 200 ml of water to 10 g or 12 g of coffee. More than 250 ml makes a thin cup.
the cup is bitter
The water is too hot. Water directly off the boil burns light roasts. Let the water stay off the heat for 30 to 60 seconds before the first pour. Do not think too much about exact degrees. Scientists at the UC Davis Coffee Center compared drip coffee at 87°C, 90°C, and 93°C, and at the same strength, the tasters found almost no difference.UC Davis 2020
the flow is too slow
Pour in smaller steps. Keep the water level low in the filter. A full filter pushes the grounds together and stops the flow.
you want a stronger cup
Use 2 bags in 1 mug. Do not use more water through 1 bag.
why we give exact numbers
Small changes to the dose and the grind cause large changes in the cup. A 2020 study in the journal Matter showed this with a mathematical model and experiments.Matter 2020 Our method was the same on a small scale. We tested 5 grind settings against 4 fill weights, across 63 prototype packets, and we kept the settings that won. The development log shows the tests.
no kettle
The format operates in places that have no equipment: an office, a hotel room, a train, a campsite. All hot water is applicable. A hotel kettle, a microwave, or hot water from a cafe will do the work.
toshi
The numbers on this page are the numbers for toshi packets: a 12 g dose, 200 ml of water, a 30-second bloom, tested across 63 prototypes. toshi starts in 2026. The waitlist is free.
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