Coffee Mug vs Sun Ninja 20oz Stainless Steel Tumbler: which is safer?
Corkcicle Coffee Mug is our pick: better on PFAS and on the overall hazard picture.
Our pick
Corkcicle
Coffee Mug
PFAS grade
A 100/100
Overall grade
B 88/100
Verdict
Buy
Hazard flags
⚑ 3
Material
Stainless steel interior, insulated walls with cork/polymer exterior
Confidence
75%
PossiblePolymer off-gassing from insulation layer
PossibleCork degradation and mold
PossibleDouble-wall seal failure
Ninja
Sun Ninja 20oz Stainless Steel Tumbler
PFAS grade
A 95/100
Overall grade
B 87/100
Verdict
Buy
Hazard flags
⚑ 2
Material
stainless steel, no stated coating
Confidence
80%
PossibleGasket and seal degradation
PossibleThermal stress and 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 mugs: see the full ranking