Coffee Brew Ratio Calculator
Set the coffee and the water follows, or set the water and the coffee follows. Eighteen methods, each with the ratio I would actually use and the range it stays sensible in.
Almost every complaint about homemade coffee comes back to one of two numbers, and people usually adjust the wrong one.
The ratio decides how strong the cup is. The grind decides how much of the coffee actually dissolves. They feel the same in the cup and they are not, which is why "it tastes weak so I brewed it longer" so often makes things worse.
Work out your numbers
20 g of coffee to 320 g of water.
Bloom with twice the coffee weight for 30 to 45 seconds first.
A millilitre of water weighs a gram, so grams and millilitres are the same number here. Weigh the water rather than pouring to a line on a jug: a jug is out by more than the difference between a good cup and a thin one.
| Method | Ratio | Workable range | Grind | Time |
|---|---|---|---|---|
| Espresso | 1:2 | 1:1.5 to 1:2.5 | Fine | 25 to 30 seconds |
| Ristretto | 1:1.2 | 1:1 to 1:1.5 | Fine | 20 to 25 seconds |
| Lungo | 1:3.5 | 1:3 to 1:4 | Fine | 35 to 45 seconds |
| Moka pot | 1:8 | 1:7 to 1:10 | Medium-fine | 4 to 5 minutes |
| Hario V60 | 1:16 | 1:15 to 1:17 | Medium-fine | 2:30 to 3:00 |
| Chemex | 1:16 | 1:15 to 1:17 | Medium-coarse | 4:00 to 5:00 |
| Kalita Wave | 1:15.5 | 1:15 to 1:16 | Medium | 3:00 to 3:30 |
| French press | 1:14 | 1:12 to 1:16 | Coarse | 4 minutes |
| AeroPress | 1:14 | 1:12 to 1:16 | Medium-fine | 1:30 to 2:00 |
| Clever dripper | 1:15 | 1:14 to 1:16 | Medium | 3:00 to 4:00 |
| Siphon | 1:15 | 1:14 to 1:16 | Medium | 1:30 steep |
| Drip machine | 1:16.5 | 1:15 to 1:18 | Medium | Machine controlled |
| Percolator | 1:15 | 1:14 to 1:16 | Coarse | 7 to 10 minutes |
| Vietnamese phin | 1:4 | 1:3.5 to 1:5 | Medium-coarse | 4 to 5 minutes |
| Cezve or ibrik | 1:11 | 1:10 to 1:12 | Extra fine | 3 to 4 minutes |
| South Indian filter | 1:5 | 1:4 to 1:6 | Medium-fine | 15 to 20 minutes |
| Cold brew concentrate | 1:6 | 1:5 to 1:8 | Coarse | 16 to 20 hours |
| Cold brew, ready to drink | 1:15 | 1:14 to 1:17 | Coarse | 16 to 20 hours |
What a ratio actually means
A ratio of 1:16 means one gram of coffee for every sixteen grams of water. Sixty grams of coffee, 960 grams of water. That is it.
Weight, not volume, and that distinction matters more than it sounds. A level scoop of coffee can vary by forty percent depending on the grind size and how the beans settled, because ground coffee is mostly air. Two scoops of a coarse grind and two scoops of a fine grind are not the same amount of coffee. A scale removes the guesswork for about fifteen pounds.
Water is simpler. A millilitre weighs a gram, so you can read grams and millilitres interchangeably. Weigh it anyway rather than filling to a line on the jug, because jug markings are routinely out by ten percent and that is the difference between a good cup and a thin one.
Strength and extraction are two different dials
This is the thing most brewing advice skips, and it explains almost every problem people have.
Strength is how much dissolved coffee ends up in the cup. You change it with the ratio. More coffee for the same water gives a stronger drink. Nothing else about the brew changes.
Extraction is how much of each ground particle dissolved. You change it with the grind, the water temperature and the contact time. Under-extract and you taste sour and sharp, because the acids come out first. Over-extract and you taste bitter and drying, because the harsh compounds come out last.
A cup can be strong and sour at the same time. It can be weak and bitter. Once you can tell which problem you have, the fix is obvious: thin means change the ratio, sour or bitter means change the grind.
The golden ratio, and why it is only a start
The Specialty Coffee Association's guideline is roughly 55 grams of coffee per litre of water, which works out at about 1:18. You will see it quoted as the golden ratio.
It is a reasonable default for filter coffee and a poor default for everything else. It is far too weak for an espresso machine, a phin or a cezve, all of which work between 1:2 and 1:11. Treat it as the middle of the filter range rather than a rule.
The numbers in the calculator are what I would pull or pour, not an average of what is published. Where a method has a genuine range, the slider shows it.
Questions
Do I really need a scale?
For espresso and pour over, yes. Ground coffee is mostly air, so a scoop varies by up to forty percent with the grind size, and that is a bigger swing than any other variable you control. A scale reading to 0.1 g costs about fifteen pounds and is the cheapest improvement available.
Is the ratio before or after brewing?
For filter methods it is the water you pour in. For espresso it is different: the ratio is the dry dose against the liquid that ends up in the cup, so 18 g in and 36 g out is 1:2. The coffee bed keeps some water, which is why the two are measured differently.
My coffee tastes weak even at 1:15. What now?
Almost always the grind rather than the ratio. Weak and sour together means under-extraction: grind finer. Weak and bitter means you are brewing a small amount of coffee for too long. Change one thing at a time.
Does the ratio change for dark roast?
The ratio stays, the grind usually moves. Dark roasts are more soluble and more brittle, so they extract faster and produce more fines. Going one step coarser is a reasonable starting adjustment.
What about milk drinks?
Milk does not count as brewing water. Work out the coffee against the water used to brew it, then add milk on top. A latte is a normal 1:2 espresso in a lot of milk, not a 1:12 brew.
Sources
- Specialty Coffee Association brewing standards The source of the 55 g per litre figure.