Tutorial: How to Brew Chemex Coffee

35 grams | 500mL | 84C | 4:00 minutes

I wanted to write a blog post about my trip to the coffeebar Sant'Eustachio in Rome and their ridiculous crema, which they create in a mysterious secrecy. However, this would confine me inside, in front of my one group Expobar to test the beans I bought there myself. And as the sunny spring weather is gorgeously present outside, I did not feel like it.

Instead, you can find a Chemex tutorial, made in my increasingly green back garden.

There are many, many Chemex tutorials to be found online, however there are several reasons to add one to the wide open space that is called 'the Internet'. First, no tutorial is the same, as no recipe is the same. It is up to the (home) barista to pick, try and choose and then decide what works for them. Second, if any manual brew method deserves a tutorial, it's the Chemex.

Why? The Chemex was designed by Peter Schlumbohm, a German inventor, in 1941. Ever since then the brew method has always been in production, amazing generation after generation. Ralph Caplan, a design author, described the Chemex as: "one of the few modern designs for which one can feel affection as well as admiration", and it is one of only few products that has become truly iconic in popular culture, resurfacing as the coffee method used by James Bond in 'From Russia, with love', and in Monica's cupboard in 'Friends'. The Chemex even acquired a place in the permanent collection of the MoMA in New York.

Although it is possible to use any paper filter or a more permanent metal filter, the Chemex really should be made with the original thicker paper filter, made by the same company 'the Chemex Corporation' in Pittsfield, USA. This thicker paper allows for a longer saturation period, which, when used correctly, can give a richer and cleaner result in your cup.

What will you need?

- coffee beans roasted for filter (light to medium roast)

- precision scale

- clean and odourless water (filtered is preferred)

- kettle and pouring kettle

- grinder

- Chemex and Chemex paper filters

- timer

- pitcher, or cup to put filter after brewing

- cups

step 1

Weigh out your coffee. A standard ratio for ground coffee and water for filter coffee is 6 grams to 100ml of water. However Chemex paper filter is thicker than the regular paper filters. The good thing is that you get a cleaner and more fresh cup of coffee. But, this also means that the water will stay in your filter a little longer before running through, allowing a longer extraction time, or a longer water-ground coffee contact time. The longer the contact time, the higher the extraction. If you over extract, your coffee will become bitter. To correct this, you will need to weigh out a little more and grind a little coarser.

For Chemex filters I use 35-40 grams of ground coffee per 500ml of brewed coffee, depending on the coffee beans I use.

This time a beautiful, full bodied, fruity and syrupy Kochere, Ethiopia roasted by Nomad Coffee Productions, located in Barcelona.

step 2

Boil your water, always use about twice the amount of water you want for your brewed coffee. Either bring it to boil, and let it cool off 1-2 minutes before use, or use a kettle which you can pre set for a certain temperature. Never use boiling water, this can result in a bitter cup of coffee. Use water at any temperature between 80-96 degrees Celsius. The colder, the longer you can make your extraction time and the softer the end result will be in taste. I used a temperature of 84 degrees Celsius.

step 3

While your water heats, grind your coffee. As I said in step 1, use a grind that is a little coarser than paper filter. You can use about the same grind you would use for a French Press, which lies between the coarseness of caster sugar and sea salt.

step 4

Place the Chemex filter in the Chemex. Put the 3 layered part in the spout, and the one layered part of the filter in the back.

step 5

Rinse the paper filter with your heated water. I always get asked why people do not know that they should rinse their paper filter. To be honest, the answer is always because they do not read... It says you should on the box of basically every single brand that I know of.

The rinsing removes the papery flavour from the filter, essential to achieve this is really saturating the paper with water. If you question the importance of rinsing the paper, taste the water used to rinse. It opened my mind to the importance of all those things we are told to do, of which we are often to lazy to actually do them.

An added bonus, the rinsing of the filter, also pre heats the glass, which gives a stable temperature during brewing.

Pour out the water used to rinse, without removing the filter.

step 6 

Add your ground coffee. Make sure you create a flat bed in the filter, in order to ensure a more even extraction.

step 7

Start your timer and start to bloom your ground coffee. If you are not sure how to do this, you can read a previous blog post on this.

step 8

Once your bloom has ended slowly keep adding water in circular movements. Never bring the water up to high to the rim, this will cause your paper filter to collapse. But also, never let all the water run through before adding more. There are several things you have to keep in mind, while pouring in the rest of your coffee.

First, you want to keep the level of water in your ground coffee about the same during the entire brewing process, or extraction period. This results in a more even extraction as there is never more or less saturation per ground coffee particle, as the amount of water is always the same. So every few seconds you add about the same amount of water, that has run through the filter.

Depending on your grind and dosage of ground coffee this is about 15ml per 7-15 seconds.

Keeping the level, or volume of water to ground coffee, the same during the entire extraction period, means that you never let all the water run through the ground coffee. In other words, when you end your brew (when you have the amount of brewed coffee you want), you will still have the same volume of water to grounds in your filter, that you had at the beginning of your brew.

Second, keep an eye on your timer for the overall extraction time. The Chemex has a little glass nub, when your brewed coffee reaches this nub you have reached 500ml. If you want to end up with a little more or a little less you can also place your Chemex on a scale while adding the water (1 gram = 1ml).

You want to reach the total amount of brewed coffee that you want to end up with in about 4 minutes, excluding your blooming time.

If your extraction period is shorter, in the future, either use a higher dosage of coffee (this will generally also give a more acidic and lighter tasting coffee) or grind a little more fine. If your extraction period is longer, the solution lies in the direct opposite.

If you want to save your brew during, and not start the entire process again with a different grind or dosage, you can play with the amount of water you add. If your brew is running through too slow, add a little more water than you initially would. As the volume of coffee to ground coffee increases, the water will start to run through faster, because gravity pulls the water through faster. If your brew is running through too fast, lower the volume of water to ground coffee a little.

Finally, while pouring, keep your motions circular to ensure an even extraction. But make sure to pour over the more dark spots and avoid the lighter parts to avoid the creation channelling.

step 9

When you reach your preferred target of brewed coffee, for 500ml up to the glass nub in your Chemex, take out the paper filter with grounds and water. Either throw away immediately, or let it drip out a little longer in a glass or pitcher on the side.

step 10

Enjoy your coffee