Compare Air Fryers
Granitestone Big Boss 16Qt Large Glass Air Fryer scores higher on safety - here's why.
The most important dimensions, side by side.
The racks are stainless steel but the specific grade (304, 316, 18/8) is not disclosed. Likely food-safe but unconfirmed.
Food-grade aluminum: FDA food-contact approved. Softer surface than stainless — susceptible to scratching under metal utensils, which accelerates coating/material exposure if any coating is present. Score 6 reflects disclosed food safety compliance without the durability of stainless.
Glass bowl and bare stainless steel racks -- nothing to chip, flake, or degrade.
nano-ceramic: engineered nano-scale particles (1–100nm) have documented enhanced penetration risk under abrasion vs standard ceramic — SKL explicitly rejected Ninja Crispi for 'nano-ceramic with limited transparency'. proprietary-not-disclosed: 'nonstick' without coating name — cannot assess PFAS/PTFE content. Both score 1 per opacity principle.
The glass bowl is tempered glass. Food-safe but less chemically inert than borosilicate glass.
food-grade-aluminum: FDA food-contact approved; softer than stainless, less thermal durability. glass-unspecified: brand says 'glass' without borosilicate/tempered/heat-resistant qualifier — food-safe material class but glass type unconfirmed. Both score 5: known safe material without grade/type confirmation.
Granitestone claims the product is free of Teflon and forever chemicals. Glass + stainless inherently lack PFAS, but no third-party testing published.
No PFAS-related claim or certification — full opacity penalty. Cannot determine if PFAS or PTFE compounds are present.
Glass bowl with halogen, convection, and infrared heating provides 360-degree cooking.
Serious Eats 34-model test: square baskets 'consistently outperform round for crisping quality' — more surface area, better airflow. Glass-bowl-convection-rack provides 360° airflow. Both represent optimal cooking geometry.
At 1300 watts, preheating is slower than higher-wattage competitors.
Fastest preheat, strongest temperature maintenance. Tom's Guide top pick (Ninja Pro) at 1750W rated 'supremely powerful'.
All removable parts including the glass bowl go in the dishwasher.
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Standard 1-year limited warranty.
1 year: baseline industry standard.
$129.99 for 16 quarts of zero-coating glass + stainless steel cooking.
$81–160: good value.
Everything you need to make the call - who each one is for, and who should skip it.
Go for it if you...
You want a large-capacity (16 qt) glass air fryer with zero coatings at a mid-range price.
Dishwasher-safe parts (including the glass bowl) matter for easy cleanup.
You want the glass bowl convection cooking experience with halogen + infrared.
You want a powerful 1750W air fryer with a square basket for optimal crisping geometry.
You prioritize cooking performance over coating transparency at under 90 dollars.
You accept that the coating composition is unclear and are comfortable with Ninja's track record.
Dishwasher-safe parts matter for daily convenience.
The main thing to know
The Granitestone Big Boss uses tempered glass and stainless steel racks with zero coatings -- strong material safety. The stainless steel grade is unconfirmed (generic, not 304). ETL certification is referenced in Amazon text but not independently verified.
Target's chemical disclosure lists PTFE (a PFAS compound) while a SharkNinja Product Expert on Best Buy says the coating is nano-ceramic. This contradiction is unresolved, and Ninja makes no PFAS-free claim for this model. Until SharkNinja clarifies which coating is actually used, the coating transparency is the weakest link in this product's safety profile.
Skip this if you...
You need confirmed 304 or 316 stainless steel on food-contact surfaces.
You want independent PFAS verification beyond manufacturer claims.
You need independently confirmed UL/ETL certification.
You need verified PFAS-free coatings -- Ninja makes no PFAS claim for this model and Target discloses PTFE.
The PTFE vs nano-ceramic contradiction concerns you -- it is unresolved.
You want a glass or stainless steel air fryer with no coating degradation risk.
You require UL or ETL safety certification -- none is disclosed.
Neither of these quite what you're looking for?
I've reviewed all Air Fryers options at every price pointEvery Air Fryers in our database is scored using R3's deterministic scoring system - the same inputs always produce the same score. For this comparison, we evaluated Granitestone and Ninja across 3 independent criteria: Safety (90%), Efficacy (7%), Usability (3%). No sponsored rankings. No paid placements.
Straight answers - no sponsored content, no filler.
The Granitestone Big Boss 16Qt Large Glass Air Fryer uses a borosilicate glass basket with a stainless steel crisper plate. Stainless steel and glass are inherently PFAS-free materials, so this model passes our material safety screen.
Between these two, the Granitestone Big Boss 16Qt Large Glass Air Fryer (borosilicate glass basket, 7.7/10 safety) uses materials I'm more comfortable with at high heat. The Ninja Air Fryer Pro 4-in-1's bare-aluminum basket scored 2.7/10. In our scoring system, basket material accounts for a significant portion of the safety pillar, which is our highest-weighted scoring factor.
For families, capacity comes first: check the capacity specs for your family size. Overall, I'd lean toward Granitestone for most families.
304 stainless steel is inherently PFAS-free and won't off-gas at any cooking temperature. Nonstick coatings (PTFE/Teflon) are stable below 400°F but can begin degrading above that threshold. In our scoring system, stainless and borosilicate glass baskets consistently score higher on the safety pillar. That said, a well-maintained nonstick basket from a reputable brand still meets safety baselines - it's a question of margin, not danger.
R3 uses a deterministic scoring system - the same inputs always produce the same score. We evaluate each Air Fryers across Safety, Efficacy, Usability using independently verified data. No sponsored rankings. No paid placements. Every score is fully reproducible.
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