Coffee-to-Water Ratio, Explained

What a coffee ratio means

A ratio compares the mass of dry coffee with the mass of brewing water.

A 1:16 ratio means:

• 1 g coffee to 16 g water;
• 15 g coffee to 240 g water;
• 30 g coffee to 480 g water.

Because one millilitre of water weighs almost one gram, weighing water is easier and more accurate than reading lines on a jug.

A simple starting table

Brewing water	Coffee at 1:16.7
200 g	12 g
250 g	15 g
300 g	18 g
500 g	30 g
750 g	45 g
1,000 g	60 g

To calculate the coffee dose:

water ÷ ratio = coffee

For example:

300 g water ÷ 16.7 = 18 g coffee

Ratio changes strength

Using more coffee with the same amount of water usually creates a stronger drink. Using less coffee usually creates a weaker one.

Common starting ranges for brewed coffee are:

• 1:15: stronger and more concentrated;
• 1:16 to 1:17: balanced starting range;
• 1:18: lighter and less concentrated.

Strength is not the same as extraction. A coffee can be strong and sour if the water has not extracted enough from the grounds. It can also be weak and bitter if a small amount of coffee has been over-extracted.

Use ratio mainly to set strength. Use grind size, time, temperature and agitation to manage extraction.

Espresso uses a different ratio

For espresso, we normally compare the dry coffee dose with the mass of liquid espresso in the cup. This is often called a beverage ratio.

A common starting recipe is:

• 18 g coffee in;
• 36 g espresso out;
• a ratio of 1:2.

Unlike a filter recipe, the second number refers to the finished beverage, not all the water used by the machine.

Typical espresso ranges include:

• Ristretto: approximately 1:1 to 1:1.5;
• Espresso: approximately 1:2;
• Lungo: approximately 1:2.5 to 1:3.

The labels are useful, but taste should still make the final decision.

What about French press and AeroPress?

The same 1:16 to 1:17 starting range works well for many French press recipes.

AeroPress recipes vary more widely. Some brew at a normal filter ratio, while others make a concentrated coffee and dilute it afterwards. Follow the recipe first, then adjust it deliberately.

How to adjust a ratio

If the coffee tastes balanced but is simply too strong or too weak:

• Too strong: use slightly more water or slightly less coffee.
• Too weak: use slightly less water or slightly more coffee.

Change the ratio in small steps. Moving from 1:16 to 1:16.5 is easier to understand than jumping directly to 1:19.

If the coffee is sour, bitter, dry or hollow, do not assume ratio is the only problem. Grind size is often the more useful next adjustment.