Thermos Stainless Steel Vacuum Insulated Food Jar
Lower concern. Bare stainless steel design avoids coatings.
Thermos vacuum food jars use stainless steel construction without non-stick or water-repellent coatings. No PFAS-prone materials identified in typical product design.
We flunk more products than we pass. This one earned its grade. How we grade
Material
stainless steel, vacuum-sealed, no coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Thermos Stainless Steel Vacuum Insulated is made of, ingredients and materials
This jar is built from food-grade stainless steel (typically 18/8 or 304 grade) with a vacuum-sealed air gap between inner and outer walls for insulation. Unlike plastic or ceramic food storage, bare stainless steel does not leach BPA, phthalates, or microplastics into food, even when heated. The vacuum design eliminates the need for polymer liners, coatings, or adhesives that might off-gas or degrade over time.
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.
Stainless steel corrosion and nickel leaching
Food-grade stainless steel (304/18-8) leaches negligible nickel under normal use, but prolonged contact with high-acid or high-salt foods may marginally increase migration. This is not a reported safety issue with Thermos jars in normal household use.
Silicone gasket degradation
The silicone seal and any silicone gaskets can degrade, crack, or harbor mold if not cleaned regularly or if exposed to prolonged moisture. Degraded seals may allow food contamination, not chemical leaching, and are easily replaceable.
What’s reassuring
Bare uncoated material
Recorded as a bare, uncoated material with no surface coating or treatment.
Microplastics
The vacuum-sealed stainless steel design contains no polymer liners, non-stick coatings, or adhesive layers that would shed microplastics or leach chemicals into food.
Source, EPA ↗BPA & bisphenols
Bare stainless steel construction avoids all plastic polymers and epoxy resins used in other food storage designs. No chemical leaching of endocrine disruptors is a feature of this material class.
Source, FDA ↗Lead
This product has no ceramic glaze, enamel, or decorative coating on food-contact surfaces, eliminating this hazard class entirely.
Source, ATSDR ↗The full breakdown
The brand's record and disclosure
Thermos (owned by Groupe SEB) has a long-established reputation in thermal food storage and has not faced major public safety recalls for chemical leaching from their stainless steel food jars. The brand does not publish detailed material safety or PFAS avoidance statements, but their core product line has been in use for decades without documented widespread contamination issues. No certifications specific to chemical safety (e.g., BPA-free labeling) are typically listed because stainless steel inherently avoids these polymers.
How it compares in its category
Stainless steel food jars show lower concern for chemical leaching compared to plastic containers (which may contain BPA, BPS, phthalates) and some ceramic glazes (which may contain lead, cadmium). They are more durable and require no replacement of liners or coatings. Competing vacuum-insulated jars from brands like Zojirushi and Tiger use similar stainless steel designs with comparable safety profiles.
If you buy it
Hand-wash rather than dishwasher to preserve the vacuum seal and minimize thermal stress to seams; do not expose to extreme temperature swings (e.g., boiling water then ice water immediately) as this can compromise the seal over years of use. The silicone gasket should be inspected annually for cracks or mold and replaced if degraded. Stainless steel is resistant to corrosion but can develop surface staining from acidic foods; this is cosmetic and does not affect safety.
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
- Thermos has made none
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Lunch Boxes
Klean Kanteen
Double Wall Vacuum Insulated Stainless Steel Food Canister Container with Leak Proof Lid
- Stainless steel body, silicone gasket lid seal
- The brand calls it PFAS-free, which we have not verified
- Silicone gasket degradation
3 hazards checked on this product. See all of them.
More lunch boxes 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.