How to Fold Chemex Filter?

  • If you aren’t a coffee-making enthusiast, you probably have a morning coffee daily without much thought. Yet, suppose you’re part of this culture. Then, there’s nothing as satisfying as using your favorite kettle and barista techniques to prepare an amazing coffee with a perfectly shaped filter paper cone. 
  • When a chemist, Peter Schlumbohm, developed his Chemex coffee-making system, he wanted to create a perfect cup of coffee and make this experience available to everyone. 
  • If the Chemex filter—and other brand accessories—sound familiar to you, keep reading. The article below researches the story, brew methods, and general use of this brand’s products.

What is the Chemex filter?

A coffee-making passion is a life-long adventure, with all its

  • brewing processes, 
  • types of grind, 
  • ideal pour method and pouring spouts, 
  • kinds of coffee makers, and so on! 

In this article, we’re breaking down the use of brew Chemex products and filter folding methods. 

Stay with us to learn how to fold a Chemex coffee filter like a barista!

So let’s start with the basics: What do filters do in general? 

They slow down (i.e., regulate) the flow of coffee to help you obtain a well-developed flavor.

According to its producer, filters by Chemex can remove even the finest sediment particles and undesirable coffee oils and fats; fractional extraction at 190-200 Fahrenheit leaves every coffee fat and bitter element in the coffee grounds, not in your cup.

Important: Chemex’s popular coffee filters are more densely woven than traditional ones. They are also up to 20-30% heavier than competitive brands. 

The story of Chemex brewer began in 1941, when Dr. Peter Schlumbohm, Ph.D., invented the first Chemex coffee maker. Since then, it’s been one of the top American design icons that continuously satisfies enthusiasts of the coffee brewing site.

Various filter options

There are three main filter alternatives that Chemex provides (all of them are eventually folding into a cone shape):

1. square,

2. circle, and

3. half-moon;

The square and circular filters—though shaped differently—work precisely the same and differ mainly in their aesthetics. 

Another choice regards the color: Do you prefer white or natural (brownish)? The latter is more environmentally friendly, while the white one requires an oxidizing bath in the production phase.

Important: You can also use regular filters on a Chemex coffee maker, but don’t be surprised if your brew ends up with a dull and paper taste. Regular filter paper cone is made from lighter and lower-grade paper, allowing water to filter through quicker.

Brewing process

Using Chemex filters is simple. After all, it’s just a basic pour-over structure that every average amateur coffee lover can have at home! 

First, heat the water in the kettle aside. Then, place a filter into the top compartment of the Chemex coffee maker. You’ll read all about the filter folding methods below. 

Tip: It’s not rocket science and may seem an obvious method, but remember that placing the filter as directed prevents vent clogging and facilitates filtration.

Pre-wet the filter with hot water from a kettle, and discard excess water. Wet the filter well before putting the coffee in. Chemex filters are super thick and can absorb many flavors, keeping them out of your cup if you forget to pre-wet enough. 

When your filter is inside the Chemex glass kettle, you can put your finely ground coffee in it. 

Drizzle the water through the filter slowly, brewing the coffee grounds. 

Then, wait for the grounds to bloom, releasing the sweet flavor. 

Finally, pour more hot water.

For one cup of coffee, use a 1:15 coffee-to-water ratio when you brew with the Chemex. 

Yet, If you feel like making a bit more or less coffee, adjust it to your taste. 

Tip: Rinsing your filter is essential to achieve a top-notch quality cup of coffee. Once you’ve placed the filter in the Chemex, run some of your boiled water through it before you add the coffee. With practice, you’ll learn rinsing and pouring in 30 seconds to let the water come to the right temperature without wasting time.

Folding traditional filter

The proper use of double-bonded paper Chemex filters is critical to achieving a well-extracted cup of coffee.

Let’s start with the traditional Chemex filter that comes as an unfolded circle.

Tip: Whether you use a round or square filter shape, you’ll always need to fold in half and then fold in half again to make quadrants. Folding ensures a straight line running through your filter. 

Now you can unfold and use the crease lines on your filter to create a conical shape. 

Continue reading to learn how to fold a Chemex filter like a barista using our instructions below. 

It starts looking like a half-moon after you fold the circle in half once. (Attention! An actual “half-moon” filter is something else; you’ll read about it in the following paragraphs). 

Now, fold it in half again, so your filter resembles a triangle with a curved bottom base made up of layers.

Look at the layered side of this triangle and separate the third and fourth layer with your fingers. Open the space up!

Your cone filter will have one side made of a single layer of paper and the other side of three layers.

Place the filter in Chemex with the three-layer side along with the spout of the Chemex. This groove is an air vent—and the pouring spout—and it allows air to escape from the lower portion of the coffeemaker, letting the coffee filter at the proper rate. 

Folding square filter

Square Chemex filter comes pre-folded in four, having many original crease lines. Still, you can additionally work on your Chemex filter by folding it into quarters to adjust the visibility of these lines.

The corner with the most folds will become the bottom of the filter—the coffee will drip from there when you start brewing.

Now, think about the imaginary line running from this corner to the opposite one and make a fold running through this line. Then, lift one part, place its edge along the imaginary line, and fold it into place. 

Repeat this folding process to achieve a kite shape: one fold on one side and the equivalent fold on the opposite. In the end, unfold the filter completely. 

One of the four original crease lines is folded the opposite way round to the other three. We want all our four folds to be the same, so fold the filter in two to reverse the fold.

Now, you can easily place the filter on the top of the Chemex kettle. 

Otherwise, fold the Chemex filter in half and again, bringing the two corners together. 

Look at the layered side of your triangle. 

By placing your finger between the third and fourth layer, open into a funnel. 

Separate the third and fourth layers with your fingers and open them up.  

Put the three-layer side towards the front spout of the Chemex. 

Important: If you use a Chemex filter this way—it will be three times thicker on one side than on the other.  It means that less coffee will pass through the thick side. Unfortunately, uneven extraction is not as innocent to the ultimate effect as it seems, and this slight variation can make a difference. 

Folding half-moon filter 

If you have a three-cup half-moon filter to fold, follow the steps below.

First, fold the half-moon in half to make a quarter circle. Then, fold up the tab.

Fold the whole filter in half again.

When you have 1/8th circle wedge, you can open out the plan you have formed with your folds and place it in your Chemex.

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Frequently Asked Questions

Chemex's simple drip coffee maker makes a stronger, richer cup of coffee than it usually would be. The Chemex paper filter is 20 to 30 percent thicker than an average filter.
Chemex works great for all, from light to medium to dark coffee roasts. You can even use it for tea. However, you will do best using a medium-coarse grind with a consistency similar to sea salt. It will allow for the best extraction and flow rate while brewing the coffee.
If your coffee filters slowly, it means that it's grounded too fine and is clogging the filter. If it filters too quickly, it's grounded too coarse, and the water passes too quickly through the larger particles.
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