Klean Kanteen · Insulated Drink Tumblers
Klean Kanteen Cup
Lower concern. Stainless steel cup with stated PFAS-free positioning.
Klean Kanteen emphasizes PFAS-free design for its stainless steel cups. No third-party lab verification found, but core material is inherently low-risk.
Brand says: “Klean Kanteen products are designed free from PFAS, BPA, and phthalates”
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel body with bamboo or plastic lid
Brand disclosure
Brand claims PFAS-free
Lab data
No public lab test
Why this grade
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
Category baseline
other is a category where PFAS exposure is more common.
Brand-stated PFAS-free
The brand states the product is PFAS-free (self-declared).
The full breakdown
What it's made of and why it matters
The Klean Kanteen Cup uses food-grade stainless steel (typically 18/8 austenitic steel) for the body, which is chemically inert and does not leach metals like aluminum or cadmium into beverages under normal use. The lid is either natural bamboo composite or food-contact plastic; bamboo introduces minimal chemical risk but may harbor bacteria if not dried fully, while plastic lids carry small risks of BPA/BPS or phthalates depending on formulation. Stainless steel is stable across temperature ranges typical for drinking and dishwashing, with no known degradation that releases harmful compounds.
The brand's record and disclosure
Klean Kanteen has publicly positioned itself as PFAS-free and markets products with sustainability messaging. The brand does not appear in major recent consumer safety recalls or enforcement actions specific to this cup model. Limited third-party independent testing data is publicly available; the brand's PFAS-free claim aligns with the material (stainless steel does not require Teflon-family coating coatings), but full supply-chain transparency on lid sourcing and manufacturing is not extensively documented in public records.
How it compares in its category
Stainless steel drinkware is one of the safest material choices for reusable cups, avoiding the non-stick coating risks of some ceramic or enamel alternatives and the microplastic/leaching concerns of lower-quality plastics. Klean Kanteen's stainless construction is comparable to other premium stainless brands (Hydro Flask, S'well) in material safety profile. The bamboo or basic plastic lid is a middle-ground choice; full silicone lids or stainless lids (offered by some competitors) may have slightly lower contamination risk if the plastic formulation is not disclosed.
If you buy it
Wash the lid thoroughly and dry it completely after each use to prevent bacterial film buildup, especially on bamboo composites. The stainless steel body is dishwasher-safe and resists corrosion; avoid prolonged contact with highly acidic or salty liquids if the seal is damaged, as microscopic corrosion can theoretically occur. Replace the lid if it becomes cracked or discolored, as compromised plastic may shed particles. Store the cup dry; bamboo lids should not remain damp for extended periods.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Bacterial growth on lid (bamboo variant)
Bamboo composite is porous and can retain moisture if not fully dried, creating conditions for microbial growth. This is a maintenance issue, not a manufacturing defect.
BPA or phthalates in plastic lid
No recalls or testing reports specific to Klean Kanteen lids for these compounds. If the plastic variant is food-grade approved, risk is low, but complete formulation transparency is not publicly available.
Stainless steel surface corrosion or leaching
Food-grade 18/8 stainless steel does not leach nickel, chromium, or other metals into beverages under normal use. Corrosion risk only arises if the coating is damaged and the cup contacts highly corrosive environments for extended periods.
Microplastic shedding from lid
Plastic lids subjected to repeated heating and dishwashing may degrade slowly and shed particles. Risk is reduced if the plastic is high-quality food-contact grade, but long-term durability testing is not published.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 78% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
Formulations and coatings change between production runs. Always check the current label before buying.
More insulated drink tumblers grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.