When you’re new to Chemex, you might wonder what ratio of water to coffee to pour in. There is the glass vessel on one side of the counter, there is the bag of roasted coffee in your hand, and suddenly you feel like an imposter in your own kitchen. The equipment are iconographic, but it doesn’t come with instructions that will make you feel confident.
It requires precision: the heavy, bonded paper filter is designed to extract nothing but purest expression of the bean. Measure too little, and you’ll have tea or even sludge; measure correctly, and you’ll achieve clarity. So as any aspiring Chemex brewer knows, a good ratio chart is a must-have for those days of measuring instead of guessing.
How to Make Perfect Chemex Coffee
In the graphic below, you can see the breakdown. As you move along the x-axis… Away from one-part coffee and toward fifteen-parts water, you go from bold to delicate. Specialty pros tend to land somewhere around sixteen, which is both sweet and acidic but doesn’t let either side overpower.
Here’s where the infographic realy comes in: It presents specific gram amounts for each cup size, eliminating the mental calculations that typically cause stress when you’re scrambling to get ready for work first thing in the morning. While your kettle steams, don’t bother trying to figure out what to do; simply reference the table, select your preferred strength, and rely on the numbers. There’s no guesswork involved.
A ritual like this shouldn’t of be stressful, right? People also tend to forget about water temperature, which plays a big role in your ratio but not nearly as much than your cup of joe’s flavor. The chart show that the best temperature is 195 to 205 degrees Fahrenheit. Anything colder and the sweet compounds won’t be extracted properly, resulting in a sour tasting brew. On the other hand, scalding hot water will burn the delicate oils and draw out bitter notes.
If you don’t have a thermometer, one easy solution is to boil your water and then wait half a minute before pouring. This brief cool down period will bring you into the best range for even extraction over all of ground. Stick with this one (and others), save more bad cups than anything else you could do!
The thing that connects all these variables are grind size. The guide stresses to use a sea salt texture, which is medium-coarse. Go finer than this, more like espresso powder, and the water will have trouble penetrating the dense Chemex filter. You’ll get a clog brewing, over-extraction, and a bitter brew.
Go coarser than this (think French press grounds), and the water will rush through in less than two minutes; the coffee won’t be fully extracted, resulting in a watery, under-extracted brew. To find this sweet spot, you need a burr grinder. It chops the beans into evenly-sized particles, unlike the messy mix of boulders and dust produced by blade grinders.
It’s all about consistency. Consistency mean that each particle dissolves in about the same time, making a clean cup instead of a muddy one. Don’t overlook the bloom phase either. The coffee will expand when hot water hits it, with all of that carbon dioxide rushing out pretty quickly. You don’t want to skip this.
The gas is pushing the water off the coffee particles. Unless you wait it out, they won’t realy get saturated. Allow the bloom to subside for half a minute or so (thirty to forty-five seconds) and let the water move into those grounds before making the main pour. Otherwise, you’re going against physics.
It is a short delay in an otherwise simple process, but it helps make the difference between control and chaos. In the end, the art of brewing a killer Chemex isn’t magic; it’s methodology. A good cup starts with good beans, which means beans that are relatively fresh (within the past couple of weeks). Next, filtered water, since coffee is ninety-eight percent water, bad water tastes like bad water even if your ratio is impeccable. Bad water tastes like bad water even if your ratio is perfect.
Record your brew time, weight, and grind setting in a simple log. Once you stumble upon something that knocks your socks off, you know exactly what you did to produce it again. This consistency makes this daily task a tiny treat. You begin asking yourself “how do I make it good?” And then, through patience and respect for the process and trust in the ratios, you arrive at the answer, right before your eyes.
Your brew is as clear as the process behind it.