Chemex FSU-100 pre-folded natural square filter papers

The Chemex FSU-100 are the unbleached natural version of the FS-100 square filters: pre-folded, cone-shaped, and designed to fit all Chemex brewers except the 1-3 cup models. Made from unbleached natural paper rather than oxygen-cleansed white paper, they're the more eco-conscious option and fully compostable after use.

Like all Chemex filters, the FSU-100 are made from bonded paper 20-30% thicker than standard pour-over filters. The bonded paper removes bitter oils, sediment, and fine grounds more effectively than a standard filter. That's what gives Chemex its clean, bright signature cup. Manufactured in the USA from responsibly harvested North American materials and certified to SFI, FSC, and PEFC standards.

• Quantity: 100 filters per box
• Material: Unbleached natural bonded paper
• Shape: Pre-folded square
• Made in: USA
• Certifications: SFI, FSC, PEFC
• Compostable and biodegradable

Brewer compatibility

Compatible with the following Chemex brewers:

• CM-6A, CM-6GH
• CM-8A, CM-8GH
• CM-10A, CM-10GH
• CM-2 (Handblown 5-cup)
• CM-3 (Handblown 8-cup)
• CM-4 (Handblown 13-cup)

Please note these filters do not fit the 1-3 cup CM-1C, CM-1GH, or the handblown 3-cup CM-1.

Ozone Coffee is the official UK importer and distributor of Chemex, offering the full range of brewers and official Chemex filter papers. If you're looking to use Chemex in your cafe or become a wholesale partner, get in touch to explore trade options and support.

What's the difference between the FSU-100 and the FS-100?

The shape, size and compatibility are identical. The FS-100 is oxygen-cleansed white paper, and the FSU-100 is unbleached natural paper. Choose on colour and processing preference rather than performance, since both filter the same way.

Which Chemex brewers do these fit?

All standard and handblown Chemex models from 5 cups upward, including the CM-6A, CM-6GH, CM-8A, CM-8GH, CM-10A, CM-10GH, CM-2, CM-3, and CM-4. They don't fit the 1-3 cup CM-1C, CM-1GH, or handblown CM-1.

Do I need to rinse the filter before brewing?

We'd recommend it. A rinse with hot water clears any trace of paper taste and preheats the Chemex vessel, so your coffee doesn't lose heat to cold glass as soon as it hits the carafe.

Are Chemex FSU-100 filters compostable?

Yes. They're unbleached, bonded paper with no chemical treatment, so the used filter and grounds can go straight into your compost bin together.

How do I fold and place the filter in my Chemex?

Open the filter into a cone, with three layers of paper sitting against the spout side and one layer against the glass on the opposite side. This keeps the pour spout clear and helps the coffee drain evenly.

What grind size works best with Chemex filters?

A medium-coarse grind, similar to coarse sand, suits the thicker Chemex paper and its longer brew time. Too fine and drawdown slows to a crawl, too coarse and extraction runs thin.

Can I use these filters in other pour-over brewers?

They're cut and folded specifically for the Chemex shape, so they won't sit correctly in a V60, Kalita Wave, or other cone or flat-bottom brewer. Stick to Chemex filters for Chemex brewers.