Cuppa · Insulated Drink Tumblers
Raincaper Tumbler 30oz
Lower concern, but brand makes no PFAS disclosure.
Stainless steel tumblers typically pose lower PFAS risk unless coated. Cuppa provides no material transparency or PFAS commitment, leaving uncertainty about any internal coating.
We flunk more products than we pass. This one earned its grade. How we grade
Material
stainless steel tumbler
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The Raincaper Tumbler is constructed from stainless steel, a non-reactive metal that does not leach metals or chemicals into beverages under normal use. Stainless steel tumblers avoid the coating-degradation and Teflon-type coating off-gassing risks associated with non-stick coatings, and they do not absorb odors or flavors. The primary concern with stainless steel is the lid or sealing components, which may contain elastomers or plastics that could off-gas or degrade with repeated hot-liquid exposure.
The brand's record and disclosure
Cuppa has not published any public PFAS or material safety disclosures for the Raincaper line, despite PFAS being a known concern in water-resistant coatings and elastomers used in tumbler seals. The brand's silence on this topic contrasts with competitors who have committed to PFAS phase-out timelines. No recalls or safety violations for this model are established in public records. Without transparency, it is difficult to assess whether the lid gasket or coating contains PFAS-class water repellents.
How it compares in its category
Stainless steel tumblers are among the safest insulated drinkware options when compared to ceramic-coated, aluminum, or glass alternatives, as they eliminate metal leaching and coating-flake risks. Many competitors in this category (e.g., Hydro Flask, YETI) have published material safety statements or third-party certifications. The Raincaper's lack of voluntary disclosure puts it in a middle position: safer in material choice, but less reassuring in brand accountability than market leaders.
If you buy it
Stainless steel tumblers are durable and do not require special care beyond hand washing to avoid damaging the seal. Avoid prolonged exposure to very hot liquids (above 185F) if the lid contains elastomers, as heat can accelerate degradation of gasket materials. Inspect the lid seal annually for cracks, discoloration, or odor; replace if damaged. Do not use bleach or harsh abrasives, as these can corrode stainless steel over time and compromise the seal integrity.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Teflon-type coating or Teflon-family coating coatings in lid/seal
If the tumbler or lid cap uses non-stick or water-resistant coatings, these may contain Teflon-type coating or PFAS. Cuppa has not disclosed the composition of the lid gasket or any inner coatings.
Elastomer or plastic lid off-gassing
The lid, gasket, or any rubber seals may be made from silicone, neoprene, or other polymers that can off-gas volatile compounds, especially when exposed to hot beverages or sunlight. No data on lid material composition is publicly available.
Stainless steel alloy nickel content
Standard food-grade stainless steel (304 or 316) contains nickel, which is generally inert in drinkware but may pose a risk for individuals with severe nickel sensitization. No public complaints or incidents have been reported for this model.
Lid or cap degradation over time
The seal components may deteriorate with age, heat cycling, or dishwashing, potentially compromising insulation or allowing leakage. Replacement lid availability and cost have not been confirmed for this specific product.
No independent third-party safety certification
Unlike some competitors, the Raincaper is not known to carry NSF, BPA-free certification, or other independent safety endorsements, making it harder to verify material claims.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Insulated Drink Tumblers
Reduce
Halo Tumbler
Stainless steel and plastic lid
Lower concern tumbler; stainless steel is inherently PFAS-safe.
✓Naturally PFAS-free material
Cuppa
To Go Tumbler
Stainless steel with plastic lid
Lower concern. Standard tumbler with no known PFAS risks.
✓Naturally PFAS-free material
Klean Kanteen
Steel Pint
18/8 stainless steel, bare metal
Lower PFAS concern. Bare stainless steel container, no coatings.
✓Bare metal or glass, no coating at all
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.