How Fine Should You Grind Coffee Beans?

If I asked you what the secret to brewing the perfect cup of coffee is, it would be perfectly normal to think that a good result depends heavily on the right choice of good coffee beans, a good coffee maker and a perfectly mineralized water, why not. While these factors are important for the outcome of the perfect brew, extracting a good coffee ground will determine the quality of your brew. In this guide, I will attempt to show you how to grind coffee beans. As well as what grinding settings to use for an optimal extraction of the flavour in your coffee beans.

Importance of Grind Size

As I mentioned before, the grind size you choose for your coffee beans plays a major role in the final result of your coffee.

Optimal Grind Size

I wouldn’t dare to say that there is an optimal grind size. But there is certainly a range of grind sizes for an optimal extraction of the flavour in your coffee beans.

Let me clarify this. There are several methods to brew your coffee available out there. Each method demands a particular grind size from your coffee beans, that is. This happens because each coffee maker works best at a certain combination of factors like time of contact between water and coffee, pressure and temperature. This makes the extraction of coffee very method-specific.

Different grind sizes for coffee beans

An extraction at high temperature and pressure might work better with fine coffee grounds. Whereas a cold brew works best with thicker grounds. But we’ll cover the specifics throughout the blog.

Results of Under/Over Extracted Coffee

Let’s see what could happen if you disregard the importance of the grind size of your coffee beans, for the sake of curiosity.

You can grind your coffee beans either too much or not enough. Both scenarios will yield a poor result.

  • Thick grinds: This underextracted coffee beans will yield a bit acidic, sour and salty result
  • Fine grinds: This overextracted coffee beans will yield a very bitter and yet hollow result. The characeristic flavour of coffee could be lost.

Why does this happen? Think about how you fry onion for a moment. Would you chop an onion in half and throw it to the pan? Or blend it until it’s a purée and then add it to the pan? No. You’d probably dice it with a knife and then fry it, same goes with coffee beans.

The organoleptic properties and availability of the different elements of the coffee beans (essential oils, tannins, minerals, proteins, alkaloids, volatile compounds, etc.) will be more or less present in the brew depending on the size of the grind. You overdo it or don’t do it well enough, and you’ll end up with a low-quality brew. In the next points, I aim to show you what grind sizes will yield the best result in each case, depending on the brewin method. However, ew should first touch on the brewing methods available to help you get a consistent grind.

Popular Grinding Methods

As I mentioned previously, I think it is sensible to talk about the most popular grinding methods and available tools out there. This way you can get a bit more familiar with them and have a better understanding of their advantages and disadvantages.

Disclaimer: Blade coffee grinders are not usually the best option to grind coffee.

Burr Grinders

Whether you use manual or powered burr grinders, you should be able to achieve very consistent coffee grounds. This grinding method is ideal since the beans will be crushed even at a low rotation speed or the burr. This way, the system won’t heat the grounds too much. This is important since we don’t want to start the extraction of the volatile molecules in our coffee grounds.

This is by far the best choice to obtain coffee grounds. However, they tend to be more expensive. A good-quality burr grinder should be more expensive than a good-quality blade grinder. Have in mind that the more comprehensive grind size settings the grinder has, the more versatility it will give you.

You can see how a burr grinder looks like and works in the video below:

Blade Grinders

You already know this is by far the worst option to obtain consistent grounds. You’ll be adding grounds of all sizes to the mix, yielding all sorts of flavours at once and lowering the quality of the brew.

On top of that, the blades in the grinder need to rotate really fast to fine-grind the beans. This is a huge downside of this method since the system will heat up, starting the extraction of volatile molecules and oils from the grounds. The result is a tasteless and bitter coffee and a ruined oily grinder. The required maintenance is also a nightmare.

However, not everything is lost if you own a blade grinder. Many people in France used to utilize this type of grinder to brew a good light bodied coffee in their French Presses and they were the happiest. Just joking, buy a burr grinder whenever you have the chance.

You can see how a blade grinder looks ike and works in the video below:

What Grind Size to Use for Each brewing Method?

We’ve got to the last bit of this blog. Finally, I’ll explain which of these grind sizes will yield a better result for each type of Brewing Methods.

Espresso

The Espresso is brewed in a brief period of time at a relatively high temperature and pressure. Taking this into account, the size of the grounds have to be extra-fine to offer a greater contact-surface to the hot water.

A holder with fine coffee grounds

Due to the amount of pressure involved in the process, the consistency and size of the grinds are especially important. Otherwise, the water can escape through the empty spaces in between the thicker particles, yielding a poor result.

Pour over

Pour over coffee makers come in different shapes. Each manufacturer will typically recommend the grind size with which the coffee maker works best.

However, the recommended size is usually between the medium to medium-fine. This is because the water stays in contact with the coffee for a longer period of time but not at a high temperature.

French Press

This method allows us to leave the coffee grounds infusing in hot water for a long period of time. This characteristic of the brewing method makes it easier for the hot water to absorb the compounds from coarse coffee grounds.

Coarse coffee grounds

This has obviously its downside. Some of the compounds the coffee beans have will be lost along the way. Some oils and proteins of the coffee won’t be present in the brew because of the limited contact-surface between the grounds and the water.

Cold Brew

As the name suggests, the brew is performed at a cold temperature. Therefore, the water will need to be in contact with the water for a really long period of time, as in 12-72h…

It’s easy to guess that we can use extra coarse coffee grounds as the water won’t need to perform an efficient extraction in a short period of time. But there is always a price and, in this case, it takes a huge amount of time to have our coffee brewed. I personally don’t have a lot of patience to wait this long for a coffee.

Drip

This is the typical cheap watery coffee you usually get in the coffee shops. The hot water goes through the coffee grounds and passes through a tiny hole to fill your cup.

The principle is similar to the pour over coffee method. The size of the grind should be medium to medium-coarsed. This is because the temperature of the water is higher than what we would need with the pour over method.

Moka Pot

The typical italian Moka is one of the most common brewing methods in Europe. The Moka builds some pressure (1.5 bar) inside its system, but the coffee is in contact with the grounds for a limited amount of time.

For this reason, the size of the grind should be medium. But you can play a bit with a medium-coarse or a medium-fine grind depending on the settings of your percolator. At the end of the day, you should always respect what the manufacturer recommends.

AeroPress

This brewing method follows a similar principle to the French Press. The only difference being that you usually brew just one cup, instead of an entire pot for the whole family.

As you guessed it, the ideal grind size for this method would be medium or fine, depending on steep time.

Siphon

This method demands a medium-fine grind size. The system builds pressure when the water is in contact with the grounds and then it is cooled to create vacuum and force the brew into the cup.

Turkish Coffee

This method calls for an extra-fine grind size, as fine as flour. Not even that, I’d say as fine as powdered sugar. This will give the Turkish coffee its characteristic black pitch and intense body.

Final Thoughts

I’d like to wrap this up by insisting on the importance of the right grind size for each brewing method. You either overextract or underextract the grounds, and you’ll add non-desired flavours to the coffee.

Finally, find a good burr grinder that includes a comprehensive grind setting. Be mindful of the grind size that better suits your prefered brewing method.

All in all, I hope this quick guide has shed some light on this issue. Have a lovely day and enjoy your cup of coffee!

Iñigo Belenguer

Hey there! My name is Iñigo and I am the biochemist who runs this website. I have enjoyed coffee since I was born and never stopped wanting to learn more. I’d love to share my passion with you.

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