S'well · Insulated Travel Mugs
S'well 24oz Tumbler with Straw
Lower concern. Stainless steel core is not a material linked to PFAS.
The main material is stainless steel double-wall construction, not a material linked to PFAS. The brand has no PFAS statement on record. The plastic lid and straw chemistry is not stated.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel double-wall with plastic lid and straw
Lab data
No public lab test
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What S'well 24oz Tumbler with Straw is made of, ingredients and materials
The S'well tumbler uses food-grade stainless steel (typically 18/8) as its inner and outer walls, which is chemically inert and does not leach metals or require non-stick coatings. The plastic lid and straw are the points of concern, these are typically polypropylene (PP) or similar thermoplastics. Because the stainless steel core does not come into contact with hot liquids directly (the double-wall design insulates), migration of plasticizers or other additives from the plastic components is minimal under normal use.
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
BPA & bisphenols
Polypropylene lids and straws may contain trace additives (including plasticizers or UV stabilizers) not publicly disclosed by S'well. Risk is low if lid/straw do not contact hot liquids directly; cold or warm (under 60°C) use presents minimal leaching.
Source, FDA ↗Microplastics
Repeated washing, freezing, or UV exposure can cause the plastic lid and straw to micro-fracture over time. Fragments are unlikely to be ingested in meaningful quantities, but replacement after 2-3 years of heavy use is prudent.
Source, EPA ↗Rubber gasket degradation and mold growth
User reports on consumer forums describe mold or odor buildup in the rubber seal if not dried immediately after washing. This is a maintenance issue, not a material defect, but indicates the design traps moisture; regular disassembly and air-drying are necessary.
Lid printing or coating adhesion
Some S'well lids bear printed logos or text. If the printing uses non-food-safe inks or adhesives, prolonged contact with acidic beverages (lemon water, vinegar) could cause flaking. S'well does not publicly detail ink or coating specifications.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Stainless steel corrosion and nickel leaching
Food-grade 18/8 stainless steel is highly corrosion-resistant and does not leach nickel under normal beverage use. No incidents reported for this product. Risk is effectively zero for this material grade.
How is this PFAS grade calculated?
The brand's record and disclosure
S'well has not published detailed material certifications or PFAS statements; this silence is typical for lifestyle drinkware brands but limits transparency. No recalls or confirmed safety incidents involving this product line are on public record. The brand markets durability and safety implicitly through its premium positioning, but does not independently verify third-party testing of its plastic components.
How it compares in its category
The S'well tumbler has lower concern than ceramic or coated-aluminum tumblers that may shed glazes or corrode. It avoids the non-stick coating hazards (Teflon-type coating off-gassing risk) present in some insulated cookware. The main trade-off versus glass or borosilicate options is that plastic lids and straws introduce minor chemical exposure; however, stainless steel core design keeps that risk lower than single-wall plastic bottles.
If you buy it
Do not heat the tumbler in a microwave or boiling water; hand-wash the lid and straw to avoid dishwasher heat stress on plastic. Inspect the rubber gasket and plastic seals annually for cracks or discoloration, which indicate degradation. Replace the straw or lid if they show cloudiness, cracks, or odors. The stainless steel body itself should last years; focus maintenance on the plastic components.
What is not known about PFAS in this product?
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- S'well has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
What are the PFAS-free alternatives to S'well 24oz Tumbler with Straw?
- stainless steel exterior, ceramic lining interior
- Ceramic coating degradation over time
3 hazards checked on this product, all on its full breakdown.
- Stainless steel body, plastic lid
- We found no PFAS statement from the brand
- Plastic lid polymer identity and leaching potential
3 hazards checked on this product, all on its full breakdown.
- Stainless steel body, no interior coating disclosed
- Silicone and plastic lid/valve leachables
3 hazards checked on this product, all on its full breakdown.
More insulated travel mugs 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.