The amount of ground coffee to use per cup of coffee or per liter often causes uncertainty. However, there are clear rules that are simple to remember and universally applicable. In this article, you'll learn everything about the correct "dosage" and the appropriate brew ratio, the best measurement method, and the universal recipe.
Dosage is not a matter of chance
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. The grind size of the coffee also plays an important role in extraction capacity, but we'll address that elsewhere.
Little 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, for example 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 are delicious. The longer and more extensive the extraction, the more bitter the coffee becomes. The so-called over-extraction leaves a dry, puckering feeling in the mouth, which in technical terms is called "astringent."
Due to the large amount of water, the coffee is simultaneously heavily diluted. Bitter, diluted, dry? Everyone knows that. Not tasty at all!
Lots of 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 insufficient to dissolve the desired amount of coffee particles. We speak of under-extraction. Under-extraction is sour and aggressive. An under-extracted espresso can also have a salty note.
Due to 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. The coffee is therefore rather strong due to the concentration of dissolved coffee particles. The concentrated strength means concentrated acidity in the flavor due to under-extraction.
Both scenarios—too little coffee in relation to water 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 coffee's inherent sweetness is crucial for it to taste balanced and delicious.
So let's go in search of the sweetness, or as it's so nicely called, the sweet spot.
Brew ratio as the key to the sweet spot
Brewing coffee is neither rocket science nor voodoo. But there are a few rules to follow when preparing coffee. One very important one is the brew ratio, which varies depending on the type of drink.
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 yields 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 express 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 brew a classic Melitta filter or a modern Hario V60 filter, an automatic drip coffee maker, 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 not a matter of chance, but ultimately a combination of the preferred taste of the majority of people and mathematics. When someone drinks filter coffee, they have a "perception expectation" born from habit and taste.
When a coffee drink 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, about 98%.
In order to brew this strength in a balanced way, we need a brew ratio of at least 1:20 and at most 1:14. Converted, this corresponds to a coffee amount 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. But then a bypass is needed to reduce the strength.
So how much ground coffee for 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?
Espresso is a small, strong drink. Under pressure and with heat, a large amount of coffee particles is 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. About 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 dispensed. With a classic espresso machine, this is not possible because it flows 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 the drink 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 machine have, in the truest sense, watered down what we knew as a classic, strong espresso. These machines brew with different proportionality and the strength of the drink changes accordingly. Yet both claim to brew "espresso."
This has major implications for the taste expectation of what an espresso is. In coffee bars, more and more people are giving baristas feedback that the espresso is too strong for them. This is due to changed habits and taste expectations.
Strength and extraction – the foundation of good brewing
In a detailed video, I've explained the relationship between strength and extraction. Here's the short summary. The proportionality of strength and extraction is the prerequisite for coffee to taste good.
Strength is the concentration of dissolved coffee particles. Each drink 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 tastily delicious or desirable. There'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 drinks targets the same value while the strength differs. Logically, because we only want to use the delicious parts of the coffee bean for all coffee drinks.
To achieve different strengths and thus different coffee drinks, adjusted dosages are used.
Why a coffee scoop doesn't make sense
Unfortunately, it's impossible to fill a spoon the same way every time. A few grams of difference happens quickly and multiplies with the number of scoops. If 9 grams of coffee per 100 ml are used instead of 7 grams for a 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 light roast coffee is significantly heavier than a heaping teaspoon of dark roast coffee. Dark coffee has more volume but less density.
If you orient yourself only by the heaping of a spoon, imprecise 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 calculating based on 200 ml.
So if we brew with the classic brew ratio of 6 grams of coffee to 100 ml of water. 4 cups of coffee should result, so we brew 800 ml with 48 grams of coffee. For each gram of coffee used, 2 grams of water remain in the coffee grounds. So in total we get 800 grams minus 2 x 48 g of coffee, which is about 700 ml of coffee and thus about 175 ml per cup. Perfect!
The principle that 2 grams of water per gram of coffee used remain in the coffee grounds applies only to filter coffee methods without pressure. With espresso and also the Aeropress, other 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 plunger pot and belongs to alternative brewing methods. Water and coffee remain in contact throughout the entire brewing process. In technical terms, this is called "full immersion."
I like to brew the plunger pot with 7 grams per 100 ml. Although the coffee is in contact with the water for a long period of 3 – 5 minutes. After the first stirring, there is hardly any more turbulence, so extraction proceeds more slowly than with classic filter drip methods.
Due to the dosage in the higher range, I still obtain sufficient strength of the coffee drink. At the same time, the extraction is somewhat lower, which leads to slightly more noticeable acidity.
With the plunger pot, the plunger with its metal mesh interrupts the extraction and separates the ground coffee and the coffee drink. Coffee oils and some sediments remain in the coffee drink – unlike with a paper filter. The coffee oils and sediments cause a less transparent coffee flavor. Due to the lower extraction and the associated acidity, the flavor is balanced. Stronger extraction would increase the bitterness of the plunger pot.
Conclusion on dosage
The amount of ground coffee to use for all drink types is more or less predetermined by the coffee's extraction capacity. That's practical because it gives you guardrails to orient yourself by.
Anyone who wants to experiment with coffee and try different brewing methods has a huge field to play in anyway. With our guide, you can first precisely determine the dosage amount and then concentrate on other factors like grind size or water temperature.
