PFAS in Insulated Travel Mugs, 67 Steel Mugs and No Coating on Record

We graded 67 insulated travel mugs and tumblers from Thermos, YETI, Stanley, Owala, S'well, Hydro Flask, RTIC, Simple Modern, Contigo and OtterBox. Every one of them is stainless steel, and none of them has a water-repellent or non-stick coating on record. They grade 70 or 80 out of 100.

That makes this one of the calmer categories on the site. The differences between the grades are small, and they come from how each mug's material is recorded rather than from anything added to the steel.

Summary comparison table

Product	PFAS grade	Construction as recorded
Thermos Guardian Stainless Steel Mug	Excellent, 80/100	Uncoated stainless steel
Thermos Icon 16 oz Stainless Steel Mug	Excellent, 80/100	Stainless steel, no stated interior coating
Thermos Stainless Steel King Travel Mug	Excellent, 80/100	Stainless steel inside and out, plastic lid
S'well 40 oz Stainless Steel Traveler	Excellent, 80/100	18/8 stainless steel inside and out, plastic lid
Contigo Autoseal West Loop Stainless Steel Travel Mug	Excellent, 80/100	Stainless steel, silicone lid seal
Owala FreeSip Stainless Steel Tumbler	Excellent, 80/100	Stainless steel, no stated coating
YETI Rambler Tumbler	Good, 70/100	18/8 stainless steel, no coating
Stanley Quencher H2.0 FlowState Tumbler	Good, 70/100	Stainless steel body, plastic lid and base
Hydro Flask All Around Travel Tumbler	Good, 70/100	Stainless steel, powder-coated exterior
RTIC Essential Tumbler	Good, 70/100	Double-wall vacuum insulated stainless steel
Simple Modern Classic Tumbler	Good, 70/100	Double-wall stainless steel
OtterBox Elevation Tumbler	Good, 70/100	Stainless steel, copper lined, powder-coated finish
OtterBox Elevation Core Colors Tumbler	Good, 70/100	Stainless steel, no coating disclosed
Contigo Superior 2.0 Travel Mug	Good, 70/100	Vacuum-insulated stainless steel

How we graded these

Every grade here is a model-based estimate built from publicly available product information and manufacturer disclosures, not a lab test performed by our team. A high score means lower concern based on reviewed sources, never PFAS-free and never safe. Across the 68 mugs the spread is 15 at 80 and 53 at 70. None of these makers publishes a PFAS statement for these mugs, and none carries third-party verification. Look up any mug in our PFAS product finder.

What separates 80 and 70

Every mug here starts from the same drink container baseline and carries the same fifteen point penalty, because its maker says nothing about PFAS. The only thing that differs is the material credit.

The 15 mugs at 80, most of them from Thermos, S'well and Owala, are recorded as bare or explicitly uncoated steel and earn our larger credit for an uncoated material. The 53 at 70, including every YETI, Stanley, Hydro Flask, RTIC, Simple Modern and OtterBox mug we graded, are recorded simply as stainless steel and earn the smaller credit for a material not associated with PFAS.

Until 17 September 2026, eight OtterBox and Contigo mugs graded 60, because their records carried no material credit at all, and an earlier version of this guide listed them at 60. That was a gap in our records rather than a difference in the mugs. They now carry the same smaller credit as other steel mugs recorded simply as stainless steel, and grade 70.

Neither tier is a finding against the mugs in it. A YETI tumbler at 70 and a Thermos mug at 80 are both plain steel as far as our records show. Choose on size, lid and price.

A correction to this guide

Earlier versions of this guide said four OtterBox Elevation models carried a water-repellent or hydrophobic coating and two Contigo mugs carried an undisclosed coating, and graded them 20 and 25. Those coatings existed only in our records. OtterBox describes Elevation tumblers as stainless steel with a copper lining and a powder-coated finish, and Contigo describes the Superior 2.0 as vacuum-insulated stainless steel. Neither mentions a water-repellent treatment. Our grading model had read words like sweat-resistant and leak-proof as evidence of a coating.

On 16 September 2026 we removed those invented coatings from 21 mugs, cups and lunch boxes, and from 392 waterproof electronics records where the same thing had happened. The same day we gave travel mugs, insulated drinkware and water bottles one shared starting point, so the same steel tumbler grades the same wherever it is listed.

What a powder-coated finish is

Several tumblers here, from OtterBox, Hydro Flask and others, have a powder-coated exterior. Powder coating is a colored finish baked onto the outside of the cup, the same process used on bicycle frames and garden furniture. It is not a water-repellent treatment, and it does not touch your drink. None of these makers publishes the chemistry of its powder coat, so we record it and do not grade it as a PFAS concern.

What to watch for

Travel mugs marketed with a non-stick or easy-clean interior. That surface touches the drink, and none of the 68 here is recorded with one, so a mug that does is worth a question to the maker.
Exterior finishes sold as water-repellent or stain-resistant with no chemistry named. We found none in this category once the records were corrected, but they exist on other drinkware.
Reading a 70 as a warning. It reflects a mug recorded simply as stainless steel rather than as explicitly uncoated, not a coating.

For other food and drink containers, see our lunch containers guide and the electric kettles guide.

Our pick

Based on available materials and data, any mug here is a reasonable choice, since all 68 are stainless steel with no coating on record. For a lidded travel mug, the Thermos Guardian Stainless Steel Mug at 80 is recorded as uncoated stainless steel. For a tumbler, the Owala FreeSip Stainless Steel Tumbler at 80 is recorded as stainless steel with no stated coating, and the YETI Rambler Tumbler at 70 is recorded as 18/8 stainless steel with no coating. These grades are estimates built from disclosed materials, not laboratory proof, and nothing here is being called PFAS-free or safe by us.

FAQ

Do stainless steel travel mugs have PFAS?

Stainless steel is not a PFAS material, and none of the 68 steel mugs we graded has a water-repellent or non-stick coating on record. What we cannot confirm is the chemistry of lids, seals and powder-coated exteriors, because none of these makers publishes a PFAS statement, which is why no mug here grades above 80.

Do OtterBox Elevation tumblers have PFAS?

OtterBox describes Elevation tumblers as stainless steel with a copper lining and a powder-coated finish, with no water-repellent treatment mentioned. They grade 70 in our data. The two Elevation tumblers in the table above graded 60 until 17 September 2026, when we gave their records the material credit other steel mugs carry. OtterBox has no PFAS statement on record for them. Earlier versions of this guide listed a water-repellent coating on four Elevation models, which was our error and was corrected on 16 September 2026.

Are YETI and Stanley tumblers PFAS-free?

The YETI and Stanley tumblers in our data are recorded as stainless steel with no coating and grade 70. Neither brand has a PFAS statement or verification on record for them, so we record lower concern based on materials, not a confirmed absence.

Why does one steel mug grade 80 and another 70?

Mugs recorded as explicitly bare or uncoated steel earn a larger material credit than mugs recorded simply as stainless steel. Both are plain steel mugs, and the ten point gap is not a finding against either.