The same bean can taste bitter, sour, or truly delicious, and often the difference lies in just one grinder setting. The grind size determines how quickly the water extracts flavors from the coffee. That is why every brewing method requires its own range.
In short: The shorter the contact time between water and coffee, the finer you should grind. Espresso requires very finely ground coffee, hand filter and AeroPress prefer medium, and French Press requires coarse. The table below is a starting point. As a first approach: If the coffee tastes sour and thin, grind finer. If it tastes bitter and dry, grind coarser. Roast level, water temperature, and the coffee-to-water ratio also influence the taste.
Why the grind size changes so much
During brewing, the water extracts aromatic compounds from the ground coffee. How quickly this happens depends heavily on the size of the particles.
Ground finer: More surface area, the water extracts more substances faster. For brewing methods where water passes through the coffee, such as espresso or hand filter, it also flows more slowly.
Ground coarser: Less surface area, the water extracts more slowly. For espresso or hand filter, it flows through more quickly.
Very simplified: Sour flavors are extracted relatively early, while bitter components increase with longer or stronger extraction. These are not strictly separated phases, but tendencies. If the coffee is too coarse for the brewing method, it often tastes rather sour and thin. If it is too fine, more bitter and dry notes frequently appear.
Grind Size Table: Which grind size for which brewing method?
| Brewing Method | Grind Size | Contact Time (approx.) | Our Starting Point |
|---|---|---|---|
| Espresso (Portafilter) | very fine | 25–30 sec. | 18 g → 36–40 g in 26–30 sec. |
| Stovetop Moka Pot (Bialetti) | fine to medium-fine | a few minutes | – |
| AeroPress | medium-fine to medium | 1–2 min. | Manufacturer's standard recipe |
| Hand Filter (V60) | medium | approx. 3 min. | approx. 650 microns, for LONGER extraction approx. 700 microns |
| French Press | coarse | approx. 4 min. | 30 g per 500 g water, 4 min. |
These figures are for orientation, not fixed values. Every grinder grinds slightly differently, and the number on the adjustment dial rarely means the same thing on two different grinders. Our micron specifications refer to the settings I use to brew our filter coffees in the Hario V60.
You can find the detailed recipes in our guides for Espresso, Hand Filter, AeroPress, and French Press.
How to set the grind size correctly
1. Start with a recipe. Determine the amount of coffee, the amount of water, and the temperature, and keep them constant while adjusting.
2. Measure brew time. For hand filter and espresso, the flow time helps you adjust: If the coffee runs significantly faster than in the recipe, grind finer. If it takes significantly longer, grind coarser. For French Press and AeroPress, you determine the steeping and waiting time yourself. Keep these constant at first and adjust the grind size according to taste.
3. Taste it. Time is an orientation, but taste is the deciding factor. Sour, thin, or watery suggests it is too coarse. Bitter, dry, or heavy suggests it is too fine.
4. Only change one thing. Adjust the grinder in small steps and brew again. If you change the grind size, amount, and temperature all at once, you won't know which change helped.
5. Keep records. Once you have found a good setting, write it down. With a new coffee or a new bag, the appropriate grind size may shift slightly.
Why the grinder is so important
For a consistent cup of coffee, the particles should be as similar in size as possible. This is achieved much better with a burr grinder (conical or flat) than with a blade grinder, which tends to chop the beans. Blade grinders create very fine and coarse pieces simultaneously. The fines are quickly over-extracted, the coarse ones barely extracted, and the cup often tastes bitter and sour at the same time.
Almost every grinder also produces some fine dust, so-called "fines." That is normal. The more consistently the grinder grinds, the easier it is to control the taste in a targeted way.
Grind fresh or buy pre-ground?
Freshly ground is the better choice because pre-ground coffee quickly loses its aroma and you cannot adjust the grind size to your brewing method.
If you don't have a grinder yet, we will grind the coffee for you in the shop. Depending on the coffee, you can choose between whole bean, hand filter, French Press, portafilter, or stovetop moka pot. If you buy pre-ground coffee, it is best to buy it in smaller quantities and store it in an airtight, dark place.
Typical errors and what you can change
The coffee tastes sour or thin
Often the grind size is too coarse for the brewing method. Grind finer in small steps.
The coffee tastes bitter or dry
Often the grind size is too fine. Grind a little coarser. Also, check if the brew time is significantly longer than in the recipe.
The coffee tastes bitter and sour at the same time
This can indicate an uneven grind, for example due to a blade grinder or a heavily worn-out grinder. With a hand filter, an inconsistent pouring technique can also contribute to this.
Hand filter or portafilter barely flows through
The grind size is likely much too fine. Adjust the grinder to be noticeably coarser.
Frequently asked questions about grind size
Which grind size is correct for filter coffee?
Usually medium. For our filter coffees in the Hario V60, I work with about 650 microns. What that looks like on your grinder depends on the model.
Which grind size is correct for espresso?
Very fine. You can find the right setting based on the time it takes for the target amount to reach the cup and by the taste.
Which grind size is correct for French Press?
Coarse. Coffee ground too fine allows more sediment through the mesh and makes pressing difficult.
Can I use one grind size for all brewing methods?
That rarely works well. For espresso, a typical filter grind is much too coarse. For our French Press recipe, we recommend a coarser setting than for the hand filter.
What does micron mean regarding grind size?
A micron is one-thousandth of a millimeter. The specification describes the approximate particle size. Most grinders do not show microns, which is why brew time and taste help more with adjusting than a number.
Do I have to change the grind size for every new bag?
Not always, but often slightly. Roast level, origin, and the age of the beans can influence how quickly the coffee extracts.
Conclusion
The grind size is one of the most important variables in coffee brewing. Start with the range from the table, keep your recipe consistent, and then adjust in small steps according to your taste. As a first approach: go finer if it tastes sour, coarser if it becomes bitter. However, the grind size is only one starting point. Roast, water temperature, and the coffee-to-water ratio also influence the taste. With a consistently grinding mill, adjusting is much easier.
About the author: Jovana is a roaster, coffeeologist, and founder of Nine Fine Roastery in Munich. She roasts the coffee for Nine Fine herself. She is also a professional soccer player.
Sources: Nine Fine Roastery – Brewing recipes for espresso, hand filter, and French Press · AeroPress – How to Use
