How To Fold Chemex Filter

How to Fold a Chemex Filter Like Pro: A Step-by-Step Guide

Did you ever wonder why you’re not harnessing the full potential of your Chemex? The issue may not be with the quality of your beans or water but with something often overlooked: how you’re folding the filter.

Chemex filters are different in their laboratory-grade material, shapes, and sizes, so it’s no surprise you’re confused.

Folding a Chemex filter is crucial for unlocking your cup’s full spectrum of flavors, something I learned only after using the Chemex for over a year.

That’s why I’ve put together a step-by-step guide on how to fold any Chemex filter like a pro.

Understanding Chemex Filters

Making coffee with a Chemex pour-over is a delicate procedure, and I cannot stress enough the importance of understanding your filters.

Chemex filters are not your typical paper filters. They are thicker than drip coffee filters, and designed to absorb unwanted sediments from ground coffee beans, oils, and bitterness to achieve a perfect cup of coffee noted for its smooth and clean taste.

Chemex material – white vs natural

Natural Vs White Chemex Filters

Chemex filters come in both white and brown varieties. They are functionally the same and are rinsed through hot water baths. The only difference is that there is an extra step with the white filter, which is the oxidizing cleansing baths.

Brown filters skip this step, thus retaining their natural color.

Different shapes of Chemex filters and their compatibility with different models

There are several types of filters you can buy for the Chemex:

  • Unfolded circled
  • Per-folded circles
  • Unfolded half moons
  • Pre-folded squares

The square-shaped coffee filter is compatible with most models of the Chemex brewer except for the pint-sized (3-cup ) and Funnex models, which require smaller filters like the Unfolded half-moon type.

You can choose between circles and squares for the rest of the Chemex brewers.

The deciding factor is only aesthetics and ease of use:

  • Circle filters sit more flush at the top,
  • Square ones are easier to remove because of their jutting edges.

Folding Chemex Filters – Step by step

Here is every way you can fold a Chemex filter.

After consistently folding my Chemex filters properly, you’ll notice that your coffee’s taste not only improves, but also becomes more consistent.

Folding circle Chemex filters

Folding Circle Chemex Filter
  1. Begin by folding the filter in half. Fold it again to bring the two corners together. Pay attention that all edges are aligned as precisely as possible.
  2. Use your fingers to create a small opening or funnel at the bottom of the folded filter. Place your finger between the third and fourth layers while doing so.
  3. Place the filter into the top portion of your Chemex coffeemaker. The three layers should be on the groove side. The groove serves as an air vent and pouring spout simultaneously. It allows proper airflow and filtration rate when brewing coffee with a Chemex. You’re also safeguarding against any clogging of vents that occurs during filtration.
  4. It’s not enough to place it correctly. You should also check that all sides of the filter are safely tucked against the glass to prevent any gaps or folds from forming.

Opening pre-folded square Chemex filters

You can also buy the circle-folded Chemex filter pre-folded. In this case, you open it as per the last part of the instructions above.

  1. Place your thumb and index finger inside the top opening of the cone, gently pulling apart the folds so that there are three leaves on one side.
  2. Carefully place it into the carafe, ensuring the three-leaf side is set against the spout when inserting it. 

Folding half-moon Chemex filters

Folding Half Moon Chemex Filters
  1. Fold the Chemex filter in half vertically so that the two rounded edges meet
  2. Fold the small tab on one end inward toward the center crease. This will create a small triangle at the bottom of your filter.
  3. Fold it in half again. 
  4. This next step requires precision: Use your finger to separate and open up only the third and fourth layers from each corner. This creates a funnel-like structure for optimal filtration.
  5. Finally, place your half-moon-shaped filter into your brewer with the three layers on the groove.

Unfolding pre-folded squares

As with the pre-folded circles, you can also buy pre-folded squares. Simply separate a 3-layered part, and place it along the spout of the carafe.

Folding square filters with the barista method

Here is a method you will see used in specialty cafés, the square “barista” method. There are a few more steps, but since no side of the filter is thicker than any other, the taste should be marginally better. Will you notice? Try it to see. I personally don’t.

But this method looks great, so it’s worth the hassle 🙂

  1. Take your folded filter (already folded in quarters) and locate the corner with more folds than the others. This will be the lowest point where water and coffee will drain through
  2. On this point, imagine or draw a line starting from the bottom and going across to its opposite end at the very top. You now have two triangles creating a diamond shape separated in the middle.
  3. Take one side point of the diamond and fold it towards the imaginary line.
  4. Flip over your filter so the fold faces downwards against your workspace.
  5. Do another fold on the opposite side.
  6. Unfold your filter completely flat while keeping all previous folds intact; note that one may seem backward, but don’t worry as we fix this next.
  7. Fold your filter in half horizontally, making sure everything lines up nicely
  8. Now you can place the Chemex coffee filter inside, and when it unfolds, it can stand up on its own.


Now you know you shouldn’t underestimate the importance of properly folded filters. It’s incredible how something as simple as paper can affect the overall result of your brew.

Armed with this knowledge, go ahead and try these techniques. Experiment with different folding methods until you find the perfect one for you. You might even want to consider other filter types such as metal and cloth.

And please remember to share your thoughts or questions by leaving a comment below.

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  1. Being an avid Chemex user, I’m thrilled to see such a detailed guide on filter folding. It’s often the little things that go unnoticed in our coffee ritual that make a significant difference. I’ve found that, in addition to the folding technique, the quality of the water and even the pace at which you pour can substantially alter the flavor profile of the brew. Working with different types of Chemex filters, I’ve discovered that the way you fold them can accentuate different notes in the coffee. It’s wonderful that Tom is spotlighting this often overlooked aspect of the brewing process.

  2. Tom: RE “Folding square filters with the barista method”, I’d love to see an illustration or video of that method. I can’t find one anywhere! I’m sure your directions are correct, but it’s a bit like learning to tie your shoes from verbal instructions!

    Thanks, Greg

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