What a ratio means
A ratio of 1:16 means 1 part coffee to 16 parts water by weight. Water is easy to measure because 1 gram is very close to 1 millilitre. So 20 g of coffee and 320 g of water is 1:16.
Common ratios for filter coffee
| Ratio | Coffee per 250 g water | Result |
|---|---|---|
| 1:15 | 16.7 g | Strong and full-bodied |
| 1:16 | 15.6 g | Balanced starting point |
| 1:17 | 14.7 g | Lighter and cleaner |
| 1:18 | 13.9 g | Delicate, tea-like |
The Specialty Coffee Association's classic guideline is about 55 g of coffee per litre, which is close to 1:18. Many home brewers prefer something a little stronger, between 1:15 and 1:17.
Ratios for other methods
- Espresso: around 1:2 (18 g of coffee makes about 36 g of liquid). See our espresso guide.
- French press: 1:15 (see the French press guide).
- Cold brew concentrate: about 1:8, then diluted. See how to make cold brew.
Strength is not the same as extraction
Strength is how much coffee is dissolved in the cup. Extraction is how much of the coffee's own material has been pulled out. The ratio mostly controls strength. Grind size, water temperature and brew time control extraction.
That is why a weak cup should not automatically be fixed with a finer grind. If the cup tastes sweet but watery, add more coffee. If it tastes sour or harsh, adjust the grind size instead.
How to dial it in
- Start at 1:16 and brew as you normally would.
- If it tastes flat but not sour, move to 1:15.
- If it tastes heavy or muddy, move to 1:17.
- Write down the numbers, so you can repeat a cup you loved.
Scaling a recipe up or down
Ratios make it easy to change the size of a brew. Divide the water by the ratio number to get the coffee.
| Water | Coffee at 1:16 | Good for |
|---|---|---|
| 250 g | 15.6 g | One mug |
| 500 g | 31 g | Two mugs |
| 750 g | 47 g | Three mugs |
| 1000 g | 62.5 g | A full carafe |
For large batches, you may need a slightly coarser grind, because the water stays in contact with the coffee for longer.
Common questions
How many tablespoons of coffee per cup?
A level tablespoon of ground coffee weighs roughly 5 g, but it varies with grind and roast. For a 250 g mug at 1:16, that is about three tablespoons. A scale is more reliable.
Does the ratio change with the roast?
Not necessarily. Darker roasts are less dense, so a scoop weighs less than a scoop of light roast. If you measure by weight, you can use the same ratio for both and adjust to taste.
Does a stronger cup have more caffeine?
Yes. If you use more coffee for the same amount of water, the cup contains more caffeine as well as a stronger flavor.
