Corkcicle · Insulated Drink Tumblers
Corkcicle Go Cup XL 30oz Mauve
No coating on record for plastic lid and gaskets creates uncertainty.
The stainless steel body is not a material linked to PFAS. The plastic lid and gaskets have undisclosed chemistry. Corkcicle has no PFAS statement on record for this product.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel with plastic lid and gaskets
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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.
Plastic lid and gasket material identity
Corkcicle does not publicly identify the plastic resin or additives in the lid or silicone gaskets. Lid plastics may contain BPA, phthalates, or PFAS depending on formulation; without material disclosure, this cannot be ruled out but is not confirmed either.
Off-gassing from plastic components at elevated temperature
Plastic lids and seals used in insulated drinkware can release volatile organic compounds (VOCs) if exposed to sustained heat above 60C. Risk is low with normal cold/room-temperature beverage use but increases if user routinely fills cup with very hot liquids.
Gasket degradation and bacterial growth
Silicone or rubber gaskets can degrade, harbor water residue, and support mold or bacterial growth if not cleaned thoroughly between uses. This is a maintenance issue, not an inherent material hazard, but requires user diligence.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Stainless steel leaching (minor concern)
18/8 stainless steel is food-contact-safe and does not leach nickel, chromium, or other metals into beverages under normal use. No established risk with this material grade in published testing.
Coating or enamel hazards
Stainless steel vessel has no glaze, enamel, or interior coating, eliminating lead, cadmium, and ceramic-leaching risks that occur in some insulated cookware.
The full breakdown
What it's made of and why it matters
The Corkcicle Go Cup XL uses 18/8 stainless steel for the main vessel, which is chemically inert and does not leach metals like aluminum or cadmium into beverages. The lid and internal gaskets are plastic components (material type not publicly specified by Corkcicle), which carry the primary material-safety question for this product. Stainless steel construction is not a material linked to coating-degradation and Teflon-type coating off-gassing risks present in some insulated cookware, supporting repeated hot and cold use.
The brand's record and disclosure
Corkcicle has not published detailed material safety disclosures or third-party certifications (e.g., FDA food-contact verification, phthalate testing) on their website or marketing materials. The brand maintains silence on PFAS use in lid seals, which is a common industry gap for insulated drinkware manufacturers. No recalls, contamination incidents, or credible safety controversies have been established for this product line in publicly available records. This absence of transparency is typical for the drinkware category but does not indicate a known hazard.
How it compares in its category
Insulated stainless steel cups with plastic lids dominate the premium drinkware market; Corkcicle is a mid-to-upper-tier brand with similar material architecture to competitors like Hydro Flask and S'well. Unlike some budget alternatives, this product avoids coated interiors, which eliminates lead-in-glaze and Teflon-type coating concerns common in enameled cookware. The plastic lid design is a standard compromise in this category; most competitors do not disclose lid material or PFAS content either, making Corkcicle broadly representative rather than exceptional.
If you buy it
Do not fill with boiling water; stainless steel containers tolerate heat, but plastic lids and gaskets may off-gas volatile compounds if subjected to prolonged high temperatures (above 60C / 140F). Hand-wash the lid and gaskets separately to inspect for degradation, warping, or discoloration, and replace them every 1 to 2 years if visible wear appears. Avoid acidic beverages stored for extended periods, as even stainless steel can develop pitting under rare conditions with certain drink types. Request material composition of the lid from Corkcicle customer service if PFAS concern is a personal priority; their silence suggests they have not tested or committed to PFAS-free formulations.
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
- Corkcicle 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
16oz Rise Tumbler
Stainless steel body, powder-coat finish
Powder-coat finish degradation
Limited concern
Seal degradation and microbial growth
Limited concern
Thermal shock to seals
Limited concern
Brand PFAS statement on record, which we have not verified.
⚠Starting grade for this product type
Klean Kanteen
Rise Tumbler
18/8 stainless steel body, likely stainless steel or silicone lid
Nickel leaching from stainless steel
Limited concern
Silicone lid degradation
Limited concern
Brand PFAS statement on record, which we have not verified.
⚠Starting grade for this product type
Klean Kanteen
20oz TKWide with Café Cap, Tofu
Stainless steel bottle, stainless steel cap
Powder-coat cap degradation over time
Limited concern
Bacterial biofilm in cap threads and seals
Limited concern
Thermal stress on seals at extreme temperatures
Limited concern
Brand PFAS statement on record, which we have not verified.
⚠Starting grade for this product type
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.