Owala · Insulated Drink Tumblers
Owala SmoothSip Slider Stainless Steel
Low risk. Stainless steel and silicone lack typical PFAS carriers.
This tumbler uses stainless steel and silicone, materials not typically treated with PFAS. No brand PFAS disclosure or public lab testing has been reported.
The better-graded swap
Ozark Trail
Ozark Trail 18 oz Stainless Steel Insulated Tumbler with Handle and Flip-Straw Lid
80/100 safety
Same rubric that flunked this product. The swap earned Excellent.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Stainless steel body, silicone slider lid
Lab data
No public lab test
What Owala SmoothSip Slider Stainless Steel is made of, ingredients and materials
The Owala SmoothSip Slider uses 18/8 stainless steel for the body, which is food-grade and highly resistant to corrosion and leaching under normal use. The slider lid is silicone, a synthetic rubber that does not off-gas volatile compounds at room temperature and tolerates cold/hot liquids without degrading. Stainless steel does not require polymer coatings (like Teflon-type coating or ceramic) that carry separate toxicity profiles, and silicone lacks the plasticizers (phthalates, BPA) found in many plastic closures.
What’s concerning
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
Microbial growth and biofilm in slider mechanism
The moving silicone slider creates a crevice where liquid can pool if not dried thoroughly after washing. Residual moisture in the groove may support mold or bacterial colonization if the bottle sits unused for days; regular cleaning and air-drying mitigate this risk.
Stainless steel manufacturing residues (oil, metal fines)
Food-grade stainless steel bottles may retain trace machining oils or metal dust from manufacturing if not properly passivated. A new bottle should be rinsed with hot water before first use; this is standard practice for stainless steel vessels.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Stainless steel leaching (nickel, chromium)
18/8 stainless steel is stable in neutral and acidic beverages at room and moderate temperatures. Leaching of nickel or chromium into water or juice is not established at normal use conditions, though prolonged contact with acidic drinks (pH <3) over years is theoretically possible.
Silicone degradation and off-gassing
Food-grade silicone used in closures does not release volatile organic compounds (VOCs) or monomers at room temperature or in contact with cold/warm drinks. No documented off-gassing events for Owala silicone sliders have been reported.
Thermal degradation of silicone under extreme heat
Silicone sliders have lower concern for use with cold and warm beverages (up to ~160F for short periods). Boiling water or repeated dishwasher cycles above 140F may accelerate rubber hardening and loss of elasticity over years, but does not produce toxic byproducts at normal use temperatures.
The full breakdown
The brand's record and disclosure
Cuppy has not published detailed material sourcing, manufacturing, or third-party safety certifications that are publicly available. The brand does not maintain a prominent safety or sustainability statement addressing PFAS, lead testing, or supply chain audits. No major recalls or health complaints tied to Owala products have been documented in U.S. regulatory databases. Absence of disclosure is not evidence of a problem, but limits independent verification of manufacturing controls.
How it compares in its category
Reusable stainless steel bottles with silicone lids are among the lowest-risk drink containers for chemical migration, outperforming plastic bottles (BPA/BPS, phthalates) and coated aluminum (potential for interior coating breakdown). Most competitors in this segment (Hydro Flask, S'well, Klean Kanteen) use similar stainless/silicone construction without documented leaching issues. The Owala's slider mechanism adds a moving part that may wear; durability and material integrity depend on routine cleaning and avoiding abrasive scourers.
If you buy it
Hand wash with warm soapy water after each use to prevent silicone odor absorption and mold growth in the seal. Inspect the silicone slider for cracks or degradation annually; replace it if visible wear appears, as a compromised seal may allow liquid to pool. Avoid dishwasher cycles above 140F if the lid is silicone-only, as prolonged heat can accelerate rubber aging. Do not use bleach or harsh solvents; mild soap and a bottle brush are sufficient.
What we don’t know
- Basis
- Model estimate, 82% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Owala has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Insulated Drink Tumblers
Klean Kanteen
20oz TKWide with Café Cap, Tofu
- Stainless steel bottle, stainless steel cap
- The brand calls it PFAS-free, which we have not verified
- Powder-coat cap degradation over time
3 hazards checked on this product. See all of them.
Klean Kanteen
16oz Rise Tumbler
- Stainless steel body, powder-coat finish
- The brand calls it PFAS-free, which we have not verified
- Powder-coat finish degradation
3 hazards checked on this product. See all of them.
Klean Kanteen
Insulated TKWide Cap
- Stainless steel bottle, plastic cap and silicone gasket
- The brand calls it PFAS-free, which we have not verified
- Silicone gasket degradation and leaching
3 hazards checked on this product. See all of them.
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.