Hydro Flask · Insulated Drink Tumblers
20 oz All Around Tumbler
Low risk. Stainless steel tumbler, no known PFAS risk.
Hydro Flask tumblers use stainless steel without reported nonstick or water-repellent coatings. The brand hasn't disclosed PFAS information, but core materials suggest lower risk.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel with vacuum insulation
Lab data
No public lab test
What 20 oz All Around Tumbler is made of, ingredients and materials
The All Around Tumbler is constructed from 18/8 stainless steel (304-grade), a food-contact alloy resistant to corrosion and leaching under normal use. The vacuum insulation layer between the inner and outer walls contains no known hazardous compounds; it functions via air removal, not chemical foaming agents. The lid assembly typically uses silicone gaskets and polypropylene, both low-migration materials at cold and warm beverage temperatures.
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.
Silicone gasket degradation
Silicone gaskets are generally food-safe but can degrade if exposed to prolonged heat, strong solvents, or repeated compression. Replacement gaskets are available; monitor for visible wear, loss of seal integrity, or odor transfer between beverages.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Metal leaching (stainless steel)
18/8 stainless steel does not release nickel, chromium, or other metals into cold or room-temperature beverages under normal conditions. Hot beverages (above 160 degrees Fahrenheit) pose theoretical but unconfirmed risk; no published incidents exist for this product or category.
Coating degradation and flaking
The tumbler uses a powder-coat or anodize finish on exterior surfaces only, away from beverage contact. No reports of interior coating degradation, flaking, or ingestion have been documented for Hydro Flask or similar stainless steel tumblers.
Bacterial or mold growth in insulation layer
The vacuum insulation is sealed and inaccessible during normal use, preventing bacterial colonization. No air pathway exists between the insulation and beverage chamber unless the seal is compromised by physical damage.
Microplastic shedding
Stainless steel does not shed microplastics. The silicone gasket and polypropylene lid are stable at cold and warm (but not boiling) temperatures and do not fragment under normal use.
The full breakdown
The brand's record and disclosure
Hydro Flask does not publicly disclose material sourcing, testing methodology, or third-party certifications for leaching or contamination. The brand has not faced recorded recalls related to toxic material migration. Their silence on PFAS use in manufacturing or coatings is notable but not unusual for the category; no independent testing has flagged this product for PFAS presence.
How it compares in its category
Stainless steel tumblers are a lower concern material choice for drinkware compared to double-wall plastic insulators and glazed ceramics. Hydro Flask's 20 oz size competes directly with Yeti, S'well, and store brands; all share the same core construction. Hydro Flask charges a premium for brand reputation rather than measurably better safety performance.
If you buy it
Wash before first use to remove any machining residue. Avoid extremely high temperatures (above 160 degrees Fahrenheit) to prevent potential seal degradation, though stainless steel itself is stable. The silicone gasket may absorb odors over time; replace it if flavors transfer between beverages. Inspect the seam and lid annually for small dents or separations that could introduce contamination pathways.
What we don’t know
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Hydro Flask has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Insulated Drink Tumblers
Klean Kanteen
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- 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
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- The brand calls it PFAS-free, which we have not verified
- Powder-coat finish degradation
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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.