Coffee Brew

How Is Coffee Brewed? – Understand How Your Cup Is Prepared


We all like to perfect our morning cup. And to do so we try all sorts of things, grinding settings, buying different beans, and looking for tutorials on the internet. The thing about this is that if you watch, or read a tutorial you’ll most likely end up following a step by step recipe without actually understanding what is going on. And there are so many factors that affect your cup’s flavor, such as the bean, the roast, or even the water and the altitude, that chances are you won’t get it exactly as it is intended to be.

Tutorials are a great starting point when you want to learn a specific method, but from there you will likely want to make tweaks to perfect your brew. And to do it you actually have to understand how coffee is brewed, which is very simple, to be able to make the tweaks in the right direction.

So by the end of this post hopefully I will have help you know what happens from the moment your coffee touches the water, and what you can do to change it.

What Is Extraction?

Coffee has a lot of different compounds that are soluble in water, so extraction is nothing more than the water dissolving those compounds and keeping them, which turns out to be your coffee drink. Simple right?

There are a few things that complicate stuff a bit…

First the beans have a very dense structure that doesn’t allow water to actually get in quickly, so to get this done, you have to increase the beans surface area, and you do this by grinding. By doing it, you are giving water access to more parts of the bean, which means more and faster extraction. So having said this, the finer the grind the more surface area and that means more extraction. Makes sense right? But there’s still one more thing to consider.

Not all soluble compounds get dissolved at the same time. Yes they are all soluble but not all of them dissolve as quickly as others. And not all of them are very pleasant in your morning cup. Actually what you are looking for is the right amount of each compound in the cup, which balances each of their flavors. That great taste you experience at a professional coffee shop is nothing more than that.

What Is There To Dissolve In Coffee?

To keep things simple, I’m going to classify these solubles by how fast they dissolve and the types of flavor they give to the coffee.

Caffeine and Acids get dissolved first. So there is no problem with caffeine, I’s probably what most people look for in their cup. When it comes to acidity, it is said that some of the best coffees in the world have great acidity. But before you leave and brew a super quick cup, let me tell you… this Acidity does not taste good (in fact it is too sour) until it is balances with the next type of flavor.

Volatile Oils and Sugars come next. Volatile oils and compounds are the ones that give the coffee it’s complex taste and aroma. They are produced during the roast. Together with the sugars they balance out the acids that were dissolved first giving them more recognizable tastes. But more on that later.

Finally, come the Organic Acids these are responsible for the bitter taste in coffee, while most like a little bitterness to round up the flavors in the cup, nobody likes to taste a cup where bitterness is mostly present.

So We can start making some conclusions already, we can assume that the perfect point of extraction is that where most acids, oils and sugars have finished dissolving and the bitter stuff is just starting to… That is where we should separate the beans from the water.

If, your coffee is too acid, or even sour where you feel it right away on the sides of your tongue, then your coffee is UNDERBREWED, this means only the first stuff was extracted and not much of the next. When you get coffee like this you will also notice that there is almost none of that delicious aftertaste that good coffee has.

If, your coffee is too bitter, it is OVERBREWED, it means that you went too far with extraction. Also, very unpleasant. You might want to check out my post on Under and over brewed coffee if you want to know more.


Variables To Take Care Of When Brewing

There are 4 main things that you can control when brewing coffee, in pretty much any method you use. Just remember in many cases these variables are not independent, sometimes one of them can affect the other, but more on that later.

Grind Setting

The grind is most times the first thing to decide. As I said before, when grinding you are increasing the bean surface area that is going to be in contact with the water. So the finer you grind extraction is going to happen faster, and the coarser you grind it is going to be slower.

So for example if you brew a cup of coffee that comes out too bitter, which means you extracted much of the last stuff, a possible way to go would be to use a coarser grind next time.

Brewing Time

Second you will want to decide the brewing time, this is the time that the beans are in contact with the water. It’s actually very simple, with more time you extract more.

When you are brewing with an immersion coffee maker this is pretty straight forward, because you decide the time and separate the beans from the water as soon as this time is over. But it becomes a bit more tricky when you use a pour over. Because here the time depends on the other variables, more on that ahead.

Coffee to Water Ratio

The next thing you want to look at is the coffee to water ratio, this is how many grams of water you are going to use per gram of coffee. For example if you use a ratio of 15 to 1, it would mean that you are going to use 1gr of coffee for each 15gr of water. This really depends on the method you use and how strong you like your coffee. If, your coffee is too weak you might want to use more coffee next time.

Sometimes, changing the ratio might also affect how much extraction there is. If you use more coffee you will have more extracted into the water but likely less extracted from each coffee bean. So, if this gives you an under extracted coffee you might also wan to try a slightly finer grind.



Temperature also affects how fast the coffee is dissolved in the water, when you use boiling water the coffee is going to extract much faster than if you use cold water. In fact cold brewing usually takes 24 to 48 hours. So this is also something you might want to consider tweaking your cup.

Just a tip here, I usually don’t recommend using boiling water, it’s better to let water off the boil for a minute or two, if the water boils during brewing it also takes away some of the nice aroma out of it.

Difference Between Pour Over And Immersion

Even though these variables work the same way there are a few differences when you are using an immersion brewer such as the Clever or the French Press, versus a pour over brewer like the Hario V60 or the Chemex.

The first big difference is the way the water makes contact with the bean, in immersion brewers the beans are sitting in the water while their flavor is being dissolved, this means that the water starts getting more and more saturated with solubles, when this happens the water starts loosing its ability to extract more from the coffee and extraction speed will slow down or in cases even stop.

Meanwhile, in pour over methods, your are always pouring fresh clean water, so extraction speed is always high, this means extraction is super efficient although you might need more coffee because it can tend to be more diluted with water.

Another difference is that with pour over methods your are a bit less in control of the time, while in immersion you just stop when the timer hits the limit, in pour over methods time is a lot influenced by the other variables. For example if you try using more coffee with the same amount of water, the water will have more coffee to go through and take more time, so while you will get a stronger cup you can also go to over brewing. Also, if you use a finer grind the water will take more time to pass. And of course if you change the coffee to water ratio time will go up as well. So have this in mind.

Getting Your Perfect Cup

So now you know this stuff, it must be much simpler to perfect your cup whatever result you have. You probably followed step by step what your were supposed to do, and didn’t think much of what you got. This is completely normal, as I said before, you are probably not using the same beans, or even the same water. But you can now make some tweaks along the way to get it better. AND ITS WORTH IT!!!

It’s a good time to start experimenting and perfecting your already favorite coffee. I really hope this post is useful, soon I will be uploading a new post with examples on how to tweak the coffee using these ideas, but meanwhile try around and if you need any help please post your questions on the comment section below, I’ll be happy to help.

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