The amount of ground coffee to use per cup of coffee or per liter often causes uncertainty. However, there are clear rules that are easy to remember and universally applicable. In this article, you'll find everything about the correct "dosage" and the appropriate brew ratio, the best measuring method, and the universal recipe.
Dosage is no accident
The amount of coffee used is the prerequisite for a balanced brew. Whether we're brewing a classic filter coffee, a French Press, or an espresso. The appropriate brew ratio, that is, the amount of ground coffee in relation to water, enables good extraction. Extraction means that water dissolves coffee particles from the ground coffee, which then create the coffee flavor in the cup.
The less ground coffee we use, the less the water can dissolve. For extraction efficiency, the grind size of the coffee also plays an important role, but we'll discuss that elsewhere.
Little ground coffee, lots of water – over-extraction
When we add a lot of water to a small amount of coffee and extract for a long time, such as in a French Press, the water dissolves a large portion of the soluble coffee particles from the coffee. The problem is that not all of these coffee particles taste good. The longer and more extensive an extraction is, the more bitter a coffee becomes. So-called over-extraction leaves a dry, astringent feeling in the mouth, which in technical terms is called "astringent."
Because of the large amount of water, the coffee is also heavily diluted. Bitter, diluted, dry? Everyone knows that. Not tasty at all!
Lots of ground coffee, little water – under-extraction
If we add a small amount of water to a large amount of coffee, we get the opposite result. The small amount of water is not sufficient to dissolve the desired amount of coffee particles. We speak of under-extraction. Under-extraction tastes sour and aggressive. An under-extracted espresso can also have a salty note.
Because of the small amount of water used, the final drink also contains little water. Although we've extracted too little from the ground coffee, it's still a lot compared to the water amount. So the coffee is rather strong due to the concentration of dissolved coffee particles. The concentrated strength means concentrated acidity in the taste due to under-extraction.
Both scenarios – too little coffee in relation and too much coffee in relation to water – have a common consequence: they are not balanced. Acidity and bitterness are not in balance. Why? Something crucial is missing: sweetness! The sweetness inherent to coffee is crucial for it to taste balanced and delicious.
So let's search for that sweetness, or as they say, the sweet spot.
Brew ratio as the key to the sweet spot
Brewing coffee is neither rocket science nor voodoo. However, there are a few rules to follow when preparing coffee. One very important one is the brew ratio, which varies depending on the beverage category.
Brew ratio is the ratio between the amount of ground coffee used and water.
18 grams of coffee in relation to 300 ml of water gives a brew ratio of 1:16.66
In other words, we can also speak of 6 grams of coffee to 100 ml or 60 grams to one liter of water. To represent the brew ratio, the water amount is divided by the amount of coffee used.
60 grams of coffee per liter is not a random example of a brew ratio, but the standard recipe for all filter coffee methods. Whether you're brewing a classic Melitta filter or a modern Hario V60 filter, an automatic filter coffee machine, or even a French Press – you'll do well with 60 grams/1 liter or 1:16.66.
How much ground coffee for filter coffee?
The dosage for filter coffee is no accident, but ultimately a combination of the preferred taste of the majority of people and mathematics. Those who drink filter coffee have a "perception expectation," created from habit and taste.
When a coffee beverage has a certain strength, we perceive it as filter coffee. This strength can be quantified, measured, and calculated.
Filter coffee tastes like filter coffee when it contains a strength of 1.10% – 1.5% dissolved coffee particles. The rest is water, by the way, so about 98%.
To brew this strength in a balanced way, a brew ratio of at least 1:20 and at most 1:14 is needed. Converted, that corresponds to a coffee amount ratio of between at least 50 grams and at most about 72 grams per liter. In the video above, I even mention a brew ratio of 1:12 as the strongest concentration. However, this requires a bypass to reduce the strength.
So how much ground coffee per 100 ml? Between 5 and 7.2 grams.
An average coffee cup holds 150 to 200 ml of liquid. The dosage should be calculated accordingly.
How much ground coffee for espresso?
The espresso is a small, strong beverage. Under pressure and with heat, a large amount of coffee particles are dissolved from a small amount of ground coffee.
Espresso also triggers a taste perception expectation in the coffee drinker. A classic espresso has a concentration of at least 7% dissolved coffee particles. So roughly 93% is water. Strong espressos reach double-digit concentrations of 10 or even 11% coffee particles.
To achieve a strength of at least 7%, a brew ratio of at most 1:3.5 is possible, for example 9 grams of ground coffee and 31.5 grams of liquid.
With espresso, the brew ratio is more difficult to measure than with filter coffee. With filter coffee, the water amount can be manually weighed and added. With a classic espresso machine, this is not possible because water is flushed directly from the brew head over the espresso.
Therefore, with espresso, the volume of the brewed espresso is measured. The term for the ratio of the brewed espresso to the amount of coffee used is beverage ratio.
Recommended ratio for a classic espresso:
1:2 which corresponds to, for example, 9 grams of ground coffee and an espresso weight of 18 grams
to
1:2.5, which corresponds to, for example, 9 grams of ground coffee and an espresso weight of 22.5 grams
Coffee machine inventions like the capsule machine or the fully automatic coffee maker have literally watered down what we knew as a classic, strong espresso. With these devices, brewing follows different proportions, and the strength of the beverage changes accordingly. Nevertheless, both claim to brew "espresso."
This has major implications for the taste expectation of what an espresso is. In the coffee bar, more and more people are giving the barista feedback that the espresso is too strong. This is due to changed habits and taste expectations.
Strength and extraction – the foundation of a good brew
In a detailed video, I explained the relationship between strength and extraction. Here's a brief summary. The proportionality of strength and extraction is the prerequisite for coffee to taste good.
Strength is the concentration of dissolved coffee particles. Every beverage has a very typical strength that is characteristic.
We achieve this concentration by extracting coffee. Not everything we can extract from the coffee bean is tasty and desirable. It's a narrow corridor that we want to extract. The target extraction corridor is 18–22%. Lower extraction leads to the sour taste of under-extraction, and higher extraction leads to the bitterness of over-extraction. The golden mean is balanced, sweet, and delicious. When we hit it exactly, we call that the sweet spot, where everything is in balance.
The extraction of all coffee beverages targets the same size while the strength differs. That makes sense, actually, because we want to use only the tasty parts of the coffee bean for all coffee beverages.
To achieve different strengths and thus different coffee beverages, adjusted dosages are used.
Why a coffee spoon doesn't make sense
Unfortunately, it's impossible to fill a spoon the same way every time. A few grams of difference happen quickly and multiply with the number of spoons. If 9 grams instead of 7 grams of coffee per 100 ml is used for filter coffee, this inevitably leads to under-extraction and thus unpleasant acidity in the taste.
Also, coffee weighs different amounts depending on the roast level and origin, and has a different volume. A heaping teaspoon of a light roasted coffee is significantly heavier than a heaping teaspoon of a dark coffee roast. Dark coffee has more volume but less density.
If you only orient yourself by the heaping of a spoon, inaccurate dosing is programmed in.
How large is a classic coffee cup?
A typical coffee cup holds about 150 to 200 milliliters. In gastronomy, such cups are often used for cappuccino as well. When visitors are expected and a certain number of cups of coffee should be brewed, I recommend using 200 ml as a basis for calculation.
So we brew with the classic brew ratio of 6 grams of coffee to 100 ml of water. 4 cups of coffee should come out, so we brew 800 ml with 48 grams of coffee. Per gram of coffee used, 2 grams of water remain in the coffee cake. So we get a total of 800 grams minus 2 x 48 g coffee, so about 700 ml of coffee and thus about 175 per cup. Perfect!
The principle that 2 grams of water per gram of coffee used are absorbed in the coffee cake only applies to filter coffee methods without pressure. With espresso and also Aeropress, different residues remain.
How many grams of coffee for the French Press
When guests come for coffee, the French Press is also a good option for brewing larger volumes of coffee. The French Press is also called a Kaffeemacher and belongs to alternative brewing methods. Water and coffee remain in contact throughout the brewing process. In technical terms, this is called "full immersion."
I like to brew the Kaffeemacher with 7 grams per 100 ml. Although the coffee is in contact with the coffee for a long period of 3–5 minutes. However, after the first stir, there is hardly any more swirling, so extraction proceeds more slowly than with classic filter drip methods.
By dosing in the higher range, I still get sufficient strength of the coffee beverage. At the same time, the extraction is somewhat lower, which leads to a slightly more perceptible acidity.
With the Kaffeemacher, the plunger with its metal mesh breaks the extraction and separates the ground coffee and the coffee beverage from each other. Coffee oils and some sediments remain in the coffee beverage – unlike with a paper filter. The coffee oils and sediments cause a less transparent coffee taste. Due to the lower extraction and the associated acidity, the taste is balanced. Stronger extraction would increase the bitterness of the Kaffeemacher.
Conclusion on dosage
The amount of ground coffee to use for all beverage types is more or less predetermined by the extraction capacity of the coffee. That's practical because it means there are guidelines you can orient yourself by.
Those who want to experiment with coffee and try different brewing methods have a huge field to play in anyway. The dosage can be precisely determined using our guide at first, and you can focus on other factors such as grind size or water temperature.
