Chemex Bonded Natural (Unbleached) Filters
Chemex's iconic unbleached paper filter - plastic-free by material, but the one paper filter on this page an independent lab actually flagged for a PFAS indicator.
The verdict: Plastic-free
Virgin pine wood pulp paper, no plastic anywhere - Chemex's thicker, "bonded" construction is a taste/flow-rate design choice, not a materials one. The plastic-free call is not in question here; the PFAS finding below is a separate, unrelated axis worth knowing about.
Verification: Manufacturer confirmed · Last reviewed
What it's made of
| Part | Material | Food contact |
|---|---|---|
| filter paper unbleached (natural) virgin pine wood pulp, 20-30% thicker than most competitors' paper | Paper unbleached / uncoated | Yes primary 🔥 |
The Chemex Natural (FSU-100) is the unbleached version of the brand's signature square filter - virgin pine wood pulp, thicker than most competing filters, and marketed as skipping any bleaching step entirely.
The reason it's flagged here: Mamavation sent Chemex Natural filters to an EPA-certified lab for a total-organic-fluorine screen - a standard indicator test for PFAS ("forever chemicals") - and it came back at 32 ppm organic fluorine, above the lab's 10 ppm detection threshold. In the same round of testing, If You Care's coffee filters and Coffee Sock's reusable cloth filters came back non-detect. Organic fluorine is an indicator, not identification of a specific PFAS compound, and Chemex's bleached white line (a different SKU) hasn't been tested by this or any other source we found - so this result is specific to the Natural (unbleached) filter, not a blanket statement about all Chemex filters. Worth noting too: the "natural" branding here doesn't track with "more processed" or "less processed" in the way you'd assume - the filter flagged is the less-processed, unbleached one.
Pros
- 100% paper, no plastic - thicker construction traps more sediment and oils
- FSC/SFI/PEFC-certified pulp sourcing per Chemex
- Iconic, widely available, fits every current Chemex brewer size
Cons
- An independent EPA-certified lab test found 32 ppm organic fluorine (a PFAS indicator) in this specific unbleached line - comparable filters from other brands tested non-detect
- Thicker paper drains slower than thinner filters, and some brewers report "stalling" without a coarser grind
- Chemex markets these as "compostable" but doesn't cite a formal BPI compostability certification the way some competitors do
Categories: Paper Coffee Filters
Sources
Every material claim above is backed by these. This is the scattered info we centralized.
- manufacturer https://chemexcoffeemaker.com/products/chemex-bonded-filters-pre-folded-squares-natural official product page; unbleached virgin pine wood pulp, thickness claim, FSC/SFI/PEFC sourcing
- manufacturer https://chemexcoffeemaker.com/pages/materials-process brand's own materials/process page
- review https://mamavation.com/food/chemex-natural-coffee-filters-pfas-forever-chemical-results.html EPA-certified-lab test (total organic fluorine via oxygen flask combustion + ion-selective electrode) found 32 ppm organic fluorine in Chemex Natural filters; If You Care and Coffee Sock filters tested non-detect in the same round
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