A Simple Guide to Extracting Coffee

A Simple and Useful Guide To Extracting Coffee For Some Awesome Delicious Results

If you’re tired of the old coffee maker and want to experience a more hands-on way of brewing coffee at home, you’ve come to the right place.

Gone are the days of buying large quantities of ground up coffee, setting them up with the coffee maker and then waiting for the collector to fill up.

We now have the tools and knowledge to make a cup of coffee far better and tastier. Today we’ll look at three major aspects of extracting (this is the more common term now as opposed to ‘brewing’) coffee regardless of what tools you use. I’ll also include some extra bits of information which I use in the extraction process, as well as some common themes I’ve found from roaster cafes in Japan.

The three major aspects are like the ISO, shutter speed and aperture in cameras. They are all correlated and so when we talk about a particular aspect, the other two will be constants to avoid confusion.

1. Grind Size

If you don’t have a mill at home, you can easily have it ground for you at the roaster shop you get it from. Of course, it would be better if you could buy the beans whole and then grind it at home.

A general rule of thumb when it comes to grinding coffee.

The coarser the grind, the less concentrated the coffee. The finer the grind, the more concentrated the coffee.

Think of a solid sugar cube and powdered sugar. When you put them in water for a few seconds and then observe the changes, the sugar cube will have reduced in size while the powdered sugar will have fully dissolved into the water.

That’s the basic principle. The more surface area you increase for the coffee to be exposed to the hot water, the more extraction you get, therefore more concentrated coffee.

If that’s the case, you may be wondering why we don’t use finer grounds to extract coffee since that would result in more concentrated coffee.

This is where we need to talk about over extraction and under extraction.

Over extraction is the dissolving of pretty much every bit of solute the coffee has. But of course, not all of the solute tastes good and when you over extract, the unwanted solute also dissolves into the water resulting in bad tasting coffee.

Under extraction, on the other hand, is when hardly any of the solutes of coffee dissolves into water. So although you don’t dissolve any of the unwanted solutes, you also fail to dissolve the tasty solutes which can make a nice cup of coffee. Under-extracted coffee also tends to be watery since there isn’t much dissolved coffee solute.

So that’s why we don’t necessarily use finer grinds all the time. But when we do, the extraction time is much shorter.

Now we’ll move on to the next major aspect.

2. Extraction Time

There’s a reason why the french press coffee, which is set up using coarse ground coffee, has a good amount of body and isn’t under extracted.

This is where the extraction time comes into play.

It’s generally said that the extraction time of the french press coffee is 5 minutes, give or take a few ten seconds.

This is most appropriate for extracting the coarse grinds.

But of course, this won’ t work for pour over coffee with a finer grind. To get the same concentration as the french press the pour over extraction should be much quicker and is usually ready within two to three minutes. With a finer grind, the extraction time must be reduced to prevent any over extraction of the coffee.

The next rule of thumb.

The shorter the extraction time, the lighter the coffee. The longer the extraction time, the stronger the coffee.

When we take grind sizes into account.

The finer the grind, the shorter the extraction time. The coarser the grind, the longer the extraction time.

Something interesting to point out are the coffee drippers. Depending on their shape and the amount of holes they have, extraction times can differ. And that’s why it’s also important to understand the unique features of the coffee drippers you have at home.

For example, I have the Kalita 3 hole dripper and the Hario V60 dripper at home. The Hario has one large hole and is cone shaped. The Kalita has three small holes and is trapezoid, which means that the Hario extracts much faster than the Kalita. So if I were to think about the grind size and the extraction time, I would use a finer grind for the Hario compared to the Kalita.

Now, you can increase the extraction time using a very thin stream of water a then using a pour and stop method. So it doesn’t necessarily mean that you need to use finer grinds for the Hario. You just have to adjust and try several methods until you find one that fits your style of pouring and your preference of the dripper type.

Moving on.

3. Water Temperature

Temperature is something I never thought about before. But after seeing quite a few baristas and coffee owners making room for thermometers in their dripper pots, I immediately began to see temperature as a major aspect to proper coffee extraction.

Many books about coffee also point out the importance of temperature.

Another important thumb of rule.

The higher the temperature, the more the extraction. The lower the temperature, the lesser the extraction. 

Over extraction is never a good thing because you’ll taste the unwanted bitterness and after tastes. The same goes for under extraction since you won’t have extracted enough of the potentially amazing flavors of the coffee at hand.

That’s why balance is the most important thing and that means optimal temperature for proper extraction.

It’d be great if you had a thermometer to measure the water temperature. On thing you want to avoid is using boiling water, or near boiling water to extract coffee. A lot of baristas I’ve talked to have said that if you don’t have a thermometer, transfer boiling water into an empty dripper pot and that should bring down temperature to an optimum level for extracting coffee.

Extraction Methods and The Three Aspects

Let’s look at the relation of the three aspects with the extraction methods used. I can’t give exact numbers here since everyone does it a little differently. But the concept is pretty much the same.

Espresso                             super fine grind, super short extraction time, super high temperature

Syphon/Aero Press       finer grind, short extraction time, high temperature

Pour over/Chemex       medium-fine to medium-corse grinds, short to medium extraction time, medium – high temperature

French Press                     course grind, longer extraction time, high temperature

I guess there’s a fourth aspect for pour-over coffee which is the pouring style. It’s kind of like being able to control time since that’s what you can do depending on how you pour. But this sort of complicates everything, and that’s why I won’t talk about this on this post.

To conclude, keep these three aspects in mind when you want to extract coffee and you’ll more or less have a very satisfying cup of coffee.

Other useful information

  1. Warm your coffee collector, mugs and dripper(if ceramic) with the hot water you’re going to extract coffee with. This prevents the extracted coffee from losing temperature quickly and keeps your mug warm much longer.
  2. I like to go for 88℃ /190℉ for light roasts. 86℃/187℉ for medium roasts and then 82℃~84℃/180℉~183℉ for medium-dark to dark roasts. Of course, this is just the way I like it, but lighter roasts usually need a higher temperature to better extract the acidities contained within them. Some people do recommend temperatures of 92℃/198℉ for extraction but I just think that’s too much. Go for what you like and think is best for your coffee.
  3. An electric mill is far better than a hand mill to get a consistent grind. One thing that you really want to avoid is an inconsistent grind of coffee since it’ll almost be impossible to properly extract the coffee.