The Chemex Coffeemaker is an iconic design; a beautiful narrow-waisted glass jug with polished wooden collar and simple leather tie. The sleek coffee apparatus is so timeless you could be forgiven for assuming the Chemex is a recent creation but it was invented in 1941 by German inventor Peter Schlumbohm.
Schlumbohm’s Most Famous Invention
Conscripted into the army during World War II, Schlumbohm returned from fighting in France unwilling to take on the reigns of his father’s successful paint and chemical business, as was expected of him. Instead he signed away his rights to inherit in return for the family’s financial support to keep him in education for as long as he wished to study. Alongside chemistry, he studied psychology, keen to understand what had lead to “the mess of a war”, his experiences on the battlefield inciting him to call for the abolition of the military and a technocratic leadership for Germany.
After graduating in chemistry Schlumbohm became an inventor, specialising in vacuum and refrigeration, the former being a key component in the latter. After visiting the United States in the early 1930s to market some of his inventions he eventually moved there, filing thousands of patents during his lifetime for a variety of chemical, mechanical and engineering breakthroughs.
For Schlumbohm, the Chemex – which he originally patented in 1939 as a laboratory ‘filtering device’ – held far less promise than the refrigeration device he exhibited at the 1939 New York World’s Fair and which he believed would make his fortune. Looking for financial investment to take the refrigerator prototype into production, he raised capital by selling a minority interest in the filtering device, setting up The Chemex Corporation to produce and market it as a coffeemaker later that same year. It was the Chemex that became Schlumbohm’s most successful and enduring invention.
Within a couple of years, Schlumbohm had simplified the design , eliminating the spout and handle in favour of a simple pouring groove. The classic Chemex design was born.
Launching in the wartime years was a challenge, requiring approval from the War Production Board for allocation of materials and production, which was eventually undertaken by the Corning Glass Works. The lack of metals in the product meant no competition over supplies with armament producers and other core industries.
The Chemex tapped perfectly into the design sensibilities of the era, which valued functional objects with a simplicity of shape and construction; indeed it complimented perfectly the influential Bauhaus aesthetic, bringing together creative design with practicality of form and skill of manufacture. It was quickly lauded by the Museum of Modern Art, cementing its place as a design classic.
In subsequent years, Schlumbohm focused on building the public profile of the Chemex by way of trade shows, prominent advertising and strategically gifting products to those in a position of influence – artists, politicians, authors and film-makers.
Today the Chemex is much loved across the world and has experienced a renaissance in recent decades, as coffee lovers around the world rekindle their love-affair with pour-over filter coffee.
How To Make Pour-Over Coffee in a Chemex Coffeemaker
To use the Chemex you will need:
- Chemex Coffeemaker (mine is the 10 cup size, which equates to approximately 1.4 litres)
- Chemex filters *
- A set of scales, accurate to within a gram or two
- Whole beans coffee ^ + a coffee grinder with adjustable grind setting
- Filtered water ~
- A measuring jug or pouring kettle
- A timer / stopwatch
* Chemex filters are much thicker than standard filters for regular coffee machines. The thicker paper traps sediment more effectively, and removes a higher volume of coffee oils, resulting in a unique taste when compared with coffee brewed using other methods. It also has an impact on how quickly the water drips through.
^ If using pre-ground coffee, look for coffee that has been ground fairly coarsely, usually labelled for use in cafetières and filter coffee machines. Espresso grind is much too fine.
~ Filtering water before using it to make your coffee (or tea, for that matter) removes unwanted substances that are present in most tap water supplies. This has a significant positive impact on the clarity and taste of your finished coffee. You can either use a filter jug to clean your water before boiling or use a kettle with a Brita filter incorporated into the design to filter and boil in one step.
How Much Coffee To Use
The ideal ratio for Chemex coffeemakers is between 55 grams and 65 grams of coffee per litre of water.
Simply scale those ratios up or down depending on how much coffee you want to make. For 500 ml of water, use 27.5 to 32.5 grams of coffee, and so on.
The exact amount of coffee will vary according to the variety and roasting levels of the coffee you choose, the grind you’ve applied and your personal preferences in how you like your coffee. Heavy roasting not only intensifies the flavour of a coffee bean, it also makes it lighter in weight, so 50 grams in weight equals many more heavily roasted coffee beans than lightly roasted ones. Don’t be afraid to adjust each time you switch to a new coffee – the ratios are just a starting point.
How To Assess The Grind
Do a test run. Weigh and grind your coffee, noting down the grind setting used.
Make your coffee following the instructions below, timing the process from the moment you pour hot water onto the coffee to the moment it pretty much stops dripping through.
It should take around 3.5 minutes for the water to drip through.
If it takes significantly longer, the grind may be too fine – water takes longer to work its way through finer grounds as they naturally pack more tightly within the filter, and so extracts a lot more from the grinds as it passes through. You may find the resulting coffee too strong and bitter. Adjust your grinder to achieve a coarser grind and try again.
If your water makes its way through much faster than 3.5 minutes, the grind may be too coarse – the resulting coffee may taste weak and insipid. Adjust your grinder to achieve a finer grind and try again.
Keep in mind that the outcome will also be affected by the individual coffee – dark roasts result in stronger, more bitter brews than light roasts and the variety, origin, growing conditions and many other factors affect the taste.
The 3.5 minutes is a guide to make adjustments again, not a fixed rule.
How To Make Pour-Over Coffee
Weigh and grind the coffee beans.
Place a Chemex filter paper into the funnel of the Chemex, with the triple folded side centred against the pouring groove.
Filter your water in a filter jug, or use a filtering kettle to boil sufficient water for the amount of coffee you want to make, plus a little extra.
Pour a little hot water into the filter to wet the paper. Pour this water out of the Chemex jug and discard.
Place your ground coffee into the dampened filter paper.
Measure 500 ml of boiled water and start pouring slowly and steadily into the Chemex, starting the timer as you start to pour. Rather than pouring only into the centre of the coffee, use circular movements to distribute the water across the surface area of the coffee. Pause during pouring if you need to, to keep the level of water a couple of centimetres below the lip of the Chemex.
Stop the timer once the coffee pretty much stops dripping through.
Gather the top edges of the coffee filter together, pick it up and quickly set it aside in a mug or on a plate. The paper and coffee grounds can be composted, if you have a compost bin.
Your coffee is now ready to pour and enjoy!
Kavey Eats attended a Chemex coffee making class run by the DunneFrankowski Creative Coffee Consultancy at The Gentlemen Baristas coffee shop as part of Brita’s #BetterWithBrita campaign. Kavey Eats received a Chemex coffee-making kit, Brita filter jug and Morphy Richards Brita Water Filter Kettle from Brita.