Cold Tumbler vs Stainless Cool Bottle: which is safer?
Ember Cold Tumbler is our pick: better on PFAS and on the overall hazard picture.
Our pick
Ember
Cold Tumbler
PFAS grade
A 100/100
Overall grade
A 92/100
Verdict
Buy
Hazard flags
⚑ 2
Material
stainless steel with silicone seal
Confidence
72%
PossibleSilicone seal degradation and microbial growth
PossibleCoatings or adhesives on printed logos
Zojirushi
Stainless Cool Bottle
PFAS grade
A 95/100
Overall grade
B 83/100
Verdict
Buy
Hazard flags
⚑ 3
Material
stainless steel bottle, no interior coating disclosed
Confidence
78%
PossibleGasket and cap material degradation
PossibleBacterial biofilm in cap assembly
PossibleThermal shock cracking or seal failure
Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →
More insulated travel drinkware: see the full ranking