Klean Kanteen · Portable Water Bottles
Klean Kanteen 27oz Wide Water Bottle with Loop Cap
Lower risk; bare stainless steel water bottle with no coatings.
Klean Kanteen's classic stainless steel bottle has no Teflon-type coating, Teflon-family coating, or water-resistant coatings. The material choice alone provides lower PFAS risk.
We flunk more products than we pass. This one earned its grade. How we grade
Material
18/8 stainless steel, no interior coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
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.
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’s reassuring
Uncoated safe material
Bare cast iron, stainless steel, carbon steel, or glass with no PFAS coating.
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.
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.
What we don’t know
- Basis
- Model estimate, 92% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Klean Kanteen has made none
Formulations change between production runs, so check the current label. How we grade.
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.