Thermos · Insulated Drinkware Tumblers
Thermos 24oz Double WALL Tumbler
Lower concern, but brand discloses nothing on PFAS.
Double-wall tumblers use stainless steel and plastics without known PFAS-prone coatings. Thermos provides no PFAS transparency. No lab data available for this model.
Shop Thermos on Amazon →Material
Stainless steel interior, plastic/polymer exterior
Brand disclosure
Brand is silent on PFAS
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.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The Thermos double-wall tumbler pairs a stainless steel interior (food-contact surface) with a polymer/plastic outer shell, typically polypropylene or similar thermoplastic. Stainless steel does not leach metals or require non-stick coatings, making it chemically inert for hot and cold beverages. The plastic exterior is not food-contact; its role is insulation and structural integrity, which reduces chemical migration risk compared to all-plastic tumblers.
The brand's record and disclosure
Thermos is a long-established brand owned by Groupe SEB; the company maintains general product safety certifications (FDA compliance for food-contact materials in the US). However, Thermos has not publicly disclosed PFAS testing results or manufacturing practices for this product line, leaving uncertainty about water-repellent or anti-stain treatments on the plastic components. No recalls or established safety violations on record for this specific tumbler model.
How it compares in its category
Double-wall tumblers with stainless steel interiors are among the safest in the reusable beverage container category because they avoid aluminum leaching and Teflon-type coating/non-stick coatings. Compared to ceramic-lined or all-plastic alternatives, this design eliminates concerns about glaze contaminants or BPA migration from temperature cycling. The trade-off is reliance on the plastic exterior, which is opaque but not a direct food-contact hazard.
If you buy it
Hand-wash the lid and plastic exterior to avoid high-temperature dishwasher stress that can degrade polymer seals; the stainless steel interior is durable. Avoid prolonged contact with acidic beverages (citrus, vinegar) at high temperatures, which can slightly increase metal ion leaching even from stainless steel, though risk remains very low. Replace the lid gasket if it becomes visibly cracked or loses elasticity, typically after 2-3 years of heavy use. Do not boil or microwave the tumbler due to the plastic exterior.
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.”
Polymer exterior durability and degradation
Repeated thermal cycling and dishwasher exposure can cause micro-crazing or discoloration of the plastic shell over years, potentially releasing small amounts of polymer residue. No specific degradation toxicity documented for Thermos tumblers, but wear inspection is prudent.
Lid seal and gasket materials (elastomer/silicone)
Thermos lids typically use silicone or rubber gaskets, which are food-safe when new. No recalls or contamination reports on record, but gaskets should be inspected for mold or degradation if lid is left wet or stored sealed.
Stainless steel interior leaching (minimal risk)
Stainless steel is passivated and highly resistant to leaching under normal use. Risk is negligible unless the interior is scratched or damaged, exposing underlying alloy; scratches alone do not represent a practical hazard in beverage-only use.
Formaldehyde or adhesive residues in plastic-to-metal bond
Double-wall assembly uses adhesives and sealants; no independent testing or recall data suggests formaldehyde or volatile organic compound release from Thermos tumblers. Food-contact surface is stainless steel, not adhesive-exposed.
PFAS in water-repellent or anti-stain coatings (plastic exterior)
Thermos does not disclose whether PFAS are used in finishes on the plastic exterior shell for stain or water resistance. The exterior is not food-contact, so direct ingestion risk is low, but manufacturing transparency gap remains.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% 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.
Safer alternatives in Insulated Drinkware Tumblers
Contigo
Byron 2.0 Stainless Steel Travel Mug Snapseal
Stainless steel, silicone gasket
Travel mug with lower PFAS concern; stainless steel typically safe.
✓Bare metal or glass, no coating at all
Thermos
Stainless King Travel Tumbler
Stainless steel exterior, vacuum-insulated, minimal internal coating
Lower concern. Stainless steel tumbler with standard design, no PFAS-prone features.
✓Bare metal or glass, no coating at all
Thermos
Stainless Steel Tumbler w/ Slide Lock Lid
Stainless steel tumbler with plastic slide lock lid
Lower concern. Stainless steel is PFAS-free; monitor lid material.
✓Bare metal or glass, no coating at all
More insulated drinkware 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.