Ember · Insulated Drink Tumblers
Ember 16 oz Smart Tumbler
Internal coating composition and PFAS status unknown from available information.
The Ember Smart Tumbler features stainless steel construction but does not publicly disclose materials or PFAS status of its internal coatings. No third-party verification exists.
The better-graded swap
Klean Kanteen
Klean Kanteen 36oz Rise Tumbler with Straw Lid
95/100 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 with unspecified internal coating/sealant
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Ember 16 oz Smart Tumbler is made of, ingredients and materials
The Ember 16 oz tumbler uses food-grade stainless steel as its primary material, which is inherently corrosion-resistant and does not leach metals under normal use. The critical unknown is the internal coating or sealant used to protect the heating element and electronics from liquid contact. Ember has not publicly specified whether this coating contains Teflon-type coating (Teflon), epoxy resins, or other polymer barriers that could degrade or off-gas over time, especially with hot beverages.
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.
Unknown / proprietary coating
A coating is recorded with no disclosed chemistry.
Unspecified internal coating degradation
The internal protective coating around the heating element is not publicly identified by material type. Thermal cycling, acidic beverages, or manufacturing defects could cause flaking or leaching into liquids, with composition unknown.
Polymer leachates from seals and lid
Silicone or elastomer seals and the lid gasket may leach softeners or degradation byproducts when exposed to hot liquids or alcohol-based drinks. No testing data is publicly available for this product.
Brand transparency and safety accountability
Ember's silence on PFAS and internal material composition is a documented gap in consumer disclosure. No third-party safety certifications (NSF, FDA compliance statements) are prominently available, making verification of manufacturing standards difficult.
What’s reassuring
Electronic component exposure to liquid
The tumbler is designed to be sealed and IP-rated, so direct liquid contact with circuitry is unlikely under normal use. Risk rises only if the seal fails or if the product is disassembled.
Stainless steel corrosion under acidic conditions
Food-grade stainless steel resists corrosion from typical beverages, though prolonged contact with strong acids (vinegar, lemon juice) may cause minor surface pitting. This does not typically release harmful levels of metals.
The full breakdown
The brand's record and disclosure
Ember does not appear to have published material safety data sheets, PFAS testing results, or coating certifications in public domains. The brand has not addressed PFAS presence or absence in response to consumer inquiries on this product line, which is notable given industry-wide scrutiny of smart drinkware. No major recalls or safety incidents have been widely documented for this model, though the product's relative newness limits long-term safety history.
How it compares in its category
Smart tumblers are a niche category with minimal standardization. Compared to conventional insulated tumblers (stainless steel only), the Ember introduces internal electronics and coatings, expanding potential exposure surfaces. Competitors rarely disclose internal coating composition either, making direct comparison difficult. Non-electronic stainless steel alternatives eliminate the coating risk entirely but sacrifice the temperature-control feature.
If you buy it
Avoid prolonged exposure of hot or acidic liquids (citrus, vinegar, wine) to the interior surfaces if possible, as these conditions may accelerate coating wear. Do not use in dishwashers or expose to extreme temperatures, as the lid and seals may contain polymers sensitive to heat cycling. Inspect the interior periodically for visible coating damage, discoloration, or flaking; discard or contact Ember if degradation appears. If Ember does not respond to a direct request for internal coating composition and PFAS status, consider this a red flag for transparency.
What we don’t know
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Ember has made none
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.