Reduce · Insulated Drink Tumblers
Reduce Aspen Glass Tumbler
Glass tumbler, lower concern. No coating risk identified.
Reduce Aspen is bare borosilicate glass with no Teflon-family coating or water-resistant coating disclosed. Glass drinkware has no inherent PFAS risk unless treated.
We flunk more products than we pass. This one earned its grade. How we grade
Material
borosilicate glass, bare
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Uncoated safe material
Bare, uncoated material (cast iron, stainless, carbon steel, or glass) with no surface treatment to contain PFAS.
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
This tumbler is borosilicate glass, a silica-based material engineered to resist thermal shock and chemical corrosion. Borosilicate contains silica, boron oxide, and alumina fused at high temperature into a stable glass matrix. Unlike soda-lime glass, borosilicate does not leach significant amounts of lead, cadmium, or other heavy metals into food or beverages under normal household conditions, even with acidic or hot contents. The bare glass formulation (no enamel, glaze, or polymer coating) eliminates coating degradation as a concern.
The brand's record and disclosure
Reduce is a drinkware brand focused on insulated and reusable containers; no major product safety recalls or contamination incidents are on record for their glass tumblers. The brand has not publicly disclosed detailed material certifications or third-party testing results for heavy metals or leaching. PFAS stance remains undisclosed, though the borosilicate glass material itself carries minimal PFAS risk. Absence of disclosure does not indicate a problem; it reflects the low-hazard nature of uncoated glass.
How it compares in its category
Borosilicate glass tumblers are among the safest reusable drinkware options, with no Teflon-type coating fume risk (unlike some non-stick metal cookware) and no BPA/BPS leaching (unlike polycarbonate or uncoated polystyrene alternatives). Most borosilicate glass products perform similarly across brands when uncoated; Reduce's offering is comparable to similar offerings from Anchor Hocking, Pyrex, and other borosilicate manufacturers. The main differentiator is durability and thermal resistance rather than chemical safety.
If you buy it
Borosilicate glass can handle temperatures from freezer to oven (typically up to 500°F) without degradation; dishwasher safe. Rapid temperature changes (ice water to hot liquid immediately) may cause thermal shock and cracking over time, so allow gradual temperature transitions. If the glass develops chips or cracks, replace it to avoid sharp edges and prevent small glass fragments from entering food. No special cleaning agents are needed; ordinary soap and water suffice.
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.”
Lead or cadmium leaching from glass
Borosilicate glass does not contain added lead or cadmium, and the base silica-boron formulation does not leach these metals under normal food/beverage contact. Uncoated glass tumbler carries no known leaching risk.
Coating degradation or flaking
Product is bare borosilicate glass with no enamel, glaze, or polymer coating, eliminating coating failure and particle ingestion as a risk pathway.
Microplastic or glass particle shedding
Borosilicate glass itself does not shed microplastics. However, thermal stress (rapid heating or cooling) or impact damage can cause chips or small fractures over time; inspect regularly and discard if cracked to prevent glass fragment ingestion.
Thermal safety and breakage risk
Borosilicate tolerates wide temperature ranges, but rapid thermal shock (e.g., pouring boiling water into a cold tumbler) may cause fracturing. Product durability depends on use pattern; normal gradual heating/cooling poses minimal risk.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 88% 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.