The Iconic Chemex Coffeemaker is a glass pour over brewing system and carafe in one. A wetted filter rests in the funnel-shaped neck of the vessel, holding the coffee grounds. Hot water is then slowly poured over the grounds, and the extraction takes place as it makes its way through the grounds into the carafe over the course of a few minutes. The result is a clean, bright and sweet brew. Invented in 1941 by chemist Peter Schlumborn and still manufactured in the U.S., the beautiful, sleek and modern design was cause for designers at the Illinois Institute of Technology to deem it “One of the best-designed products of modern times” in 1958, and it can even be found in the collection of the Museum of Modern Art in New York City.
Chemex and filter (we use and recommend CoffeeSock reusable cotton filters), scale, kettle, and timer.
A standard ratio for Chemex brewing is 1/16 (coffee/water) and we would recommend doses between 36gm coffee/ 576gm water to 50gm coffee/ 800gm water. While we suggest these ratios as a good starting place, playing around a little with ratios can make for interesting changes in your results, and should simply be based on your preferences. While you may find yourself unaccustomed to weighing water or using a timer while brewing coffee, you will find that these prove very helpful when trying to achieve consistent results.
We recommend a medium fine grind for use in the Chemex, somewhere between sand and table salt. Different grind sizes will yield different results during extraction based on the surface area that is coming into contact with water (finer grind = more surface area coming into contact with water). Experiment and find what suits your tastes best.
Place filter in the Chemex and wet thoroughly with water. This allows the filter to form a seal, and (if using paper) also helps to remove a papery taste you might find otherwise. Carefully drain water and then add grounds, creating a mound in the base of the funnel.
Boil water and pour into a gooseneck kettle, weighing to match the coffee to water ratio you have chosen to brew. Let rest for a few seconds, allowing the temperature to drop to approximately 205.
Pour a small amount of water over the grounds, making sure that the surface is covered, but just so. This process is known as “the bloom” and allows the coffee to saturate and release gases.
After roughly 45 seconds and avoiding the center and edges, begin to slowly pour water in a circular motion over the grounds, breaking the crust created in the bloom. The slurry (wet grounds) should be kept saturated while the extraction takes place. Try to keep it somewhat low and concentrated, allowing the maximum amount of consistent contact between the grounds and water. Keep slowly adding water in the same circular motion until your kettle is empty. Depending on your grind and the amount of coffee you have used, brewing times will vary. A 36gm Chemex brew should take somewhere around 4 minutes, with your kettle empty around 3. If you find your brewing time ending too quickly, your grind is likely to coarse, and if it is taking too long, it is likely too fine.
After brewing, discard grounds (great for compost or on plants), and thoroughly rinse CoffeeSock filter.
Boil filter again every once in a while to clean out coffee oil residuals.
If using paper filters, simply toss filter with grounds in garbage or compost, and give vessel a rinse once empty.
All photos by Kristan Lieb