Ember · Insulated Drink Tumblers
Personalized Ember Tumbler - Slate Black / 16 oz
Ember silent on PFAS; internal coating composition undisclosed.
Ember's smart tumbler uses stainless steel externally but keeps its internal coating formula secret. No PFAS claim or testing data comes from the brand.
The better-graded swap
Mira
Mira Stainless Steel Vacuum Insulated Tumbler Flip Lid
80/100 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 body, proprietary internal coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Personalized Ember Tumbler - Slate Black is made of, ingredients and materials
The Ember tumbler uses a stainless steel exterior (inherently stable and non-leaching) paired with a proprietary internal coating that Ember has not publicly disclosed. This internal coating is critical because it contacts hot beverages directly and controls thermal conductivity and flavor transfer. Without specification of the coating material, polymer type, or additives, it is impossible to rule out leaching or degradation risks under normal or prolonged use.
What’s concerning
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
Unknown / proprietary coating
A coating is recorded with no disclosed chemistry.
Internal coating leaching or degradation
Proprietary coating composition is undisclosed. Polymer or resin coatings can leach additives or break down under hot beverage contact if not food-grade certified. No published test data or certification standard provided by Ember.
Coating adhesion and microparticle shedding
If the internal coating uses an adhesive or is multi-layered, mechanical stress from thermal cycling or impact could cause flaking. Ember does not address durability specifications or what happens if coating fails.
Thermal conductivity mismatch and heat exposure
The internal coating's thermal properties are unspecified. If coating or adhesive has a lower melting point than stainless steel, sustained contact with boiling water could compromise integrity. Manufacturer heat limits should be followed strictly.
PFAS
Ember is silent on PFAS. Proprietary coatings in food-contact products sometimes contain PFAS for non-stick or water-repellent properties. Absence of disclosure does not exclude presence.
Source, ATSDR ↗What’s reassuring
Heavy metals
No recalls or complaints on public record for Ember tumblers involving lead, cadmium, or other heavy metals. However, lack of published coating composition means heavy metal pigments cannot be ruled out.
Source, FDA ↗The full breakdown
The brand's record and disclosure
Ember markets premium smart drinkware but has maintained silence on material composition, PFAS content, and third-party safety certifications. The company has not published ingredient disclosures, safety data sheets for coatings, or responses to consumer inquiries about chemical composition. This absence of proactive transparency is a red flag in an industry where coating safety is well-established as a consumer concern.
How it compares in its category
Smart tumblers are a niche product; most competitors (Contigo, Hydro Flask, YETI) disclose stainless steel + food-grade polymer or ceramic liners and provide material safety documentation. Ember's refusal to specify its proprietary coating places it outside normal disclosure norms for drinkware. Standard insulated tumblers with transparent liners or ceramic coatings carry less uncertainty.
If you buy it
Do not expose to prolonged heat above manufacturer specifications (check documentation). Inspect the interior coating regularly for scratches, peeling, or discoloration; discontinue use if coating degrades. Hand wash only; avoid abrasive scrubbing or dishwasher. Request written material safety documentation from Ember before purchase if you have sensitivities. Consider a competing brand with published coating specifications if chemical transparency is important to you.
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.