Klean Kanteen · Portable Water Bottles
Klean Kanteen 27oz Wide Water Bottle with Loop Cap
Lower concern. Bare stainless steel water bottle, no coatings.
Klean Kanteen's classic stainless steel bottle has no Teflon-type coating, Teflon-family coating, or water-resistant coatings. Inherently lower PFAS risk by material choice alone.
Shop Klean Kanteen on Amazon →Material
18/8 stainless steel, no interior coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Uncoated safe material
Bare, uncoated material (cast iron, stainless, carbon steel, or glass) with no surface treatment to contain PFAS.
The full breakdown
What it's made of and why it matters
This bottle is 18/8 stainless steel, meaning it contains 18% chromium and 8% nickel. The steel is food-grade and non-reactive, so it does not leach metals or require interior protective coatings. The absence of any polymer coating or enamel eliminates two major contamination pathways that affect many competitor bottles. Loop cap is typically polymer; material composition not publicly specified by brand.
The brand's record and disclosure
Klean Kanteen has built brand identity around minimal material transparency and sustainability claims, but does not publish independent third-party certifications (NSF, FDA, or ISO) for this specific model. The company has faced no major recalls or safety controversies on record related to their stainless steel bottles. Brand does not publicly disclose PFAS testing results or manufacturing practices.
How it compares in its category
Stainless steel bottles avoid the coating-leaching and thermal degradation risks that affect plastic-lined or enamel-coated alternatives. This design is considered a safer baseline in the reusable bottle category. However, competitors like Hydro Flask and S'well also use bare stainless steel, so this product is standard practice rather than differentiated.
If you buy it
Hand-wash to avoid dishwasher-induced surface corrosion over time. Avoid prolonged contact with acidic liquids (lemon water, vinegar), which can gradually pit stainless steel. The loop cap should be inspected regularly for wear or odor accumulation, as polymer caps are not replaceable on this model. No heat-damage risk to the steel body itself, but cap polymer should not contact boiling water.
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.”
Nickel leaching from stainless steel
18/8 stainless steel contains 8% nickel. Leaching is minimal in neutral pH water but increases with acidic beverages (citrus, vinegar, sports drinks). Risk is low for typical daily water use but notable for users with nickel sensitivity.
Cap material composition and degradation
Loop cap material is not publicly disclosed by Klean Kanteen. Polymeric caps can off-gas or degrade over extended sun exposure or repeated hot-water contact. No specific safety incidents reported for this model's cap.
Surface corrosion and pitting over time
Prolonged contact with chlorinated water, salt water, or acidic beverages can cause pitting corrosion on bare stainless steel. This is cosmetic and slow but may eventually compromise structural integrity if bottle is heavily used in harsh conditions.
Bacterial growth in cap seals
The loop cap design may trap moisture or residue in crevices. Inadequate drying or cleaning can allow bacterial biofilm formation, a concern for any reusable bottle. Not unique to this product but common maintenance issue.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 92% 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.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
More portable water bottles 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.