Who says that a chemist can’t get involved in designing coffee brewing methods? The Chemex is a classic and elegant brewing device that was designed by the German chemist, Peter J. Schlumbohm. It may seem like a device that was born out of the third wave brewing movement, but it has been in production since 1941.
Schlumbohm is the owner of more than 300 patents due to his numerous inventions, but the Chemex and the water kettle are one the most famous. They are even part of permanent collections in some museums, like the Museum of Modern Art in New York, the Smithsonian, the Corning Museum of Glass, and the Philadelphia Museum.
SPANISH VERSION: Chemex: Historia y Guía de Extracción
In order to create this coffeemaker, Schlumbohm was inspired by two laboratory apparatus: his laboratory glass funnel and his Erlenmeyer flask. He added an air channel to the funnel in order to leave space for the air displaced by the liquid dripping into the vessel to escape easily. He also added a “belly button” to the Erlenmeyer, and combined it with the modified glass funnel. Finally, the wooden handle was added, creating a one-piece, heatproof, borosilicate glass coffee brewer called the Chemex.
Let’s get down to how to use this masterpiece and discuss the beautiful brew that you can make with this device at home.
The original 1941 Chemex. Credit: keithwaynebrown
What to Expect From a Chemex
The Chemex relies on a pour over method, which means that the water passes through a bed of coffee and a filter, normally made out of paper. In contrast to say a French Press, the Chemex will give you a remarkably clean cup of coffee. Chemex paper filters are 20-30% heavier than other filters so they retain more of the suspended oils during the brewing process, keeping solids from passing through the filter.
Chemex is for sharing. Credit: @abbyberm
SEE ALSO: Hario V60: The History & Brewing Guide
How to Brew Chemex Like a Pro
1. Grind Size:
In order to yield a high-quality brew from a Chemex, the grind size should be slightly finer than that used for the French Press, but should not look like sand. The Chemex is prone to stalling completely if your grind is too fine. And a grind that is too coarse will under extract and pour through too fast.
2. Coffee Dose/Brew Ratio:
As I mentioned in the French Press brewing guide, choose your brewing ratio according to taste. This time keep in mind that Chemex produces a light-bodied brew, so you may want to start with a 1:10 ratio (1 gram coffee per 10 ml of water). Increase the coffee dose or use less water to achieve your preferred taste.
Chemex produces a light-bodied brew. Credit: @jaylamode
3. Water Temperature:
Try brewing with water between 90-96 degrees celsius, to begin with. I encourage you to experiment with temperature if you have an accurate way to do so because it can change the cup dramatically for some coffee lovers.
4. Brew Time:
The extraction time on a Chemex is between three to five minutes depending on your pouring technique and grind size. You will have to experiment with the variables to consistently achieve your preferred brew time.
Chemexin and Surfin. Credit: @maroon_coffee
Start by heating your water to the desired temperature and grind the desired amount of fresh coffee appropriately. Place the filter correctly inside your Chemex – there is a complete Filter Folding 101 section on how to fold the filter. Always rinse the filter to reduce any tastes that may affect the brew; this will also warm up the device. Then, add the coffee to the brewer.
For the next step, I highly recommend using a gooseneck kettle. Start pouring the water (90-96º) in circles from the center outwards. For the first pour, remember to add double the amount of water to coffee you are using and let it pre-infuse for 30 seconds. If your coffee is fresh enough, you will see an amazing bloom, which is the reaction of the coffee when water is added and the carbon dioxide is released.
Always pre-infuse. Credit: @sl0wlylife
Keep pouring slowly in circles avoiding the walls of the brewer. Do not add all the water at the same time. I recommend what is known as a pulse pour by adding 30 grams of water each time and waiting for a few seconds. This will create a better extraction, but don’t let the grinds go dry, or you will lose the ideal temperature. Reach the desired amount of brew, dispose of the spent grounds, and serve. Most important of all, enjoy it and take time to appreciate the changes when drinking the coffee as the temperature drops.
Personally, this is the brewing method I enjoy the most due to its clean finish and aroma that is maximized by the Chemex shape. Try it with a Geisha and you will know what magic tastes like. Alternatively, experiment with other Chemex filter types such as Coffee Sock‘s organically grown, untreated cotton version.
I love Chemex due its clean aroma and taste. Credit: @abbyberm2
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Article written by F. Solano and edited by A. Guerra.
Perfect Daily Grind.