How to Choose and Fold Chemex Filters by Size

If you've ever tried brewing coffee in a Chemex, you’ve likely noticed how the carafe and filter holder are fused into one sleek piece — but figuring out which filter fits your specific Chemex model isn’t always obvious. Whether you’re working with a small one-cupper or a large 13-cup version, the shape and fold of your filter matters for clean extraction and proper flow.

Quick answer: Chemex offers three common sizes — 1–3 cup (with half-circle filters), and 6–10 cup (with either square or round filters). Each size uses a unique filter shape: 1–3 cup brewers use half-circle filters, while 6–8–10 cup models use either square or round options, all folded the same basic way. Always match the filter shape to your Chemex’s brew capacity.

What Is a Chemex and Why Does Filter Shape Matter?

The Chemex is a classic pour-over coffee maker, combining a pouring funnel and glass decanter into a single vessel. Its design is elegant but functional — the thick paper filter helps remove sediment and oils, producing a clean, bright cup. But not all Chemex brewers use the same filter. Depending on the size, you’ll need a different shape: half-circle for smaller brewers, square or round for medium to large ones.

Common Chemex Sizes and Their Corresponding Filters

Here’s a breakdown of the typical Chemex models and the filters they require:

• 1–3 cup (half-circle filter): Often found in the smallest models, whether with a wood + leather handle or glass handle. These use a distinctive half-moon shaped filter.
• 6–8–10 cup (square or round filter): Available in both wood + leather and glass handle styles. These mid-sized to larger brewers use either a square or a round filter — both are common and widely available.

How to Fold Your Chemex Filter (Step-by-Step)

No matter the shape — half-circle, square, or round — Chemex filters are folded the same way before brewing. While the article does not provide explicit folding steps, here’s the general method used for all official Chemex filters:

1. Lay the filter flat with the triple-layered side facing you.
2. Fold the filter in half so the three-layered edge meets the single-layered edge, forming a cone.
3. Open the filter so that the side with three layers is on the pouring spout side of the Chemex. This helps direct water flow and supports proper extraction.

For visual learners, Chemex provides official diagrams — as seen in the linked images — showing both the square and round fold techniques. Always ensure the folded edge sits against the spout for optimal brewing.

Frequently Asked Questions

What size Chemex do I have?

Chemex brewers are categorized by cup capacity: 1–3 cup (small), 6 cup, 8 cup, and 10 cup (medium to large), up to a 13-cup model. The 1–3 cup versions often use half-circle filters, while 6–10 cup models typically use either square or round filters.

What kind of filter does a 6-cup Chemex use?

A 6-cup Chemex usually takes a square or round filter. Both shapes are designed to fit the 6-cup brewer and are folded in the standard Chemex method with the thicker side aligned toward the spout.

Are Chemex filters universal?

No, Chemex filters are not universal. They come in specific shapes — half-circle for 1–3 cup brewers, and square or round for 6–10 cup models. Always match the filter shape to your brewer’s size and handle style.

How do I fold a Chemex filter?

Folding a Chemex filter involves laying it flat, folding it in half to create a cone, then opening it so the three-layered side faces the spout. This directs brew water properly and ensures even extraction. Official Chemex diagrams show detailed steps for square and round folds.

Do all Chemex models use the same filter?

No. Smaller Chemex models (1–3 cups) use a unique half-circle filter. Larger models (6–10 cups and 13 cups) use either square or round filters. The filter shape must match the brewer size for proper brewing.

Recommended FrontStreet Beans for Chemex Brewing

For Chemex pour-over, we recommend FrontStreet Coffee’s Ethiopia Humbera – a bright, floral Ethiopian single origin with notes of jasmine, bergamot, and stone fruit. Its clean profile shines through Chemex’s thick filters. Also try the FrontStreet Yirgacheffe, offering citrusy brightness with hints of blueberry and honey. For a more balanced cup, the FrontStreet Classic Blend delivers chocolatey malt tones with a smooth mouthfeel. All three work beautifully with the Chemex’s clean extraction style. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.