# Frying, saute and specialty pans: research notes

Date: 2026-10-25. Scope: open stovetop pans for frying, searing and sautéing: frying pans and skillets (sloped sides, no lid), sauté pans (straight sides, usually lidded), sauteuses and chef's pans, woks and stir-fry pans, grill pans, crêpe pans and single-burner griddles, and other shaped pans (paella, omelette, tamagoyaki). Not saucepans, stock pots, Dutch ovens or braisers (sibling `saucepans`), not multi-piece sets (`cookware-sets`), not ovenware or sheet pans (`baking-pans`, `baking-sheets`), not lids, splatter screens or induction interface discs (`cookware-stove-accessories`), and not electric skillets or electric woks, which are appliances. Overlaps: deep lidded sauté pans sold as "braisers" or "rondeaux" belong to `saucepans`; a cast-iron skillet used for baking stays here. Two-burner griddle plates stay here too: `cookware-stove-accessories`'s own notes hand pans, woks and griddles back to `frying-pans`, so this leaf claims both single- and two-burner griddle plates under the `pan_shape` value "crêpe pan or griddle". A sauteuse évasée (shallow, flared sides) counts as a sauté pan here; a deeper, rounder sauteuse shades into a saucier and belongs to `saucepans`.

Quote labels: **verbatim** = the sentence in quotation marks was in text I read myself (curl plus HTML stripping, or pdftotext on a downloaded PDF); **fetched excerpt** = the fetch tool summarised or lightly reworded the page; **search excerpt** = the claim came from a search-engine summary because the page itself would not load. A search-excerpt-only number does not go in category.json.

Raw text for every verbatim quote is in the scratchpad (`/private/tmp/claude-501/-Users-amnbh-Desktop-dev-zamana/94e1e673-5231-41fe-8b68-7a624ab5c8d8/scratchpad/frying-pans/*.txt`). The session's web search budget ran out part way through (shared across concurrent runs), so later sources were reached by known URLs, Shopify product JSON and the Internet Archive.

## Seed

Seed output (recorded verbatim):

```
=== Example entry (from an unrelated category) ===
category: car-tyres
what this shows: a number that is on every listing and still needs a judgement attached, because experts know it only compares within one manufacturer's range.

<example>
{
  "id": "treadwear_grade",
  "label": "Treadwear grade",
  "definition": "A number moulded on the tyre's side, from a US test, that estimates how long the tread lasts relative to a reference tyre set at 100.",
  "why_experts_care": "A 600 should last roughly twice as long as a 300, which is the single biggest driver of cost per mile. The catch experts repeat is that each manufacturer runs its own test, so the number is reliable for comparing tyres within one brand and loose across brands. Softer, grippier tyres sit low on this scale on purpose.",
  "kind": "numeric",
  "unit": "grade",
  "range": { "min": 60, "max": 1000, "typical": "Most everyday tyres sit between 300 and 700." },
  "roles": ["annotation", "sort_key"],
  "novice_answerable": false,
  "source": "listing",
  "listing_field_hint": "Listed as UTQG, usually as three values together, for example 500 A A. Treadwear is the first.",
  "backfill_cost": "low",
  "backfill_note": "If absent from the listing, the manufacturer's spec sheet always has it.",
  "visual": { "chartable": true, "encoding": "position on a horizontal scale, with the grip grade as a second mark so the trade-off shows" },
  "priority": { "narrows_set": 3, "cost_to_answer": 3 },
  "evidence": ["nhtsa_utqg", "tirerack_explainer"]
}
</example>

Judgement that would accompany it:
{
  "claim": "Treadwear grades can be compared across brands as a rough guide but not as a ranking.",
  "confidence": "high",
  "sources_disagree": true,
  "note": "The regulator describes the test as standard. Specialist reviewers say manufacturers calibrate differently. We side with the reviewers because they test the tyres."
}

=== Persona ===
A watchmaker, who thinks in tolerances and in what the price buys that you cannot see

Ask yourself two things and write the answers under 'Seed' in notes.md:
  1. What is the frying-pans equivalent of the example above?
  2. What would this persona notice first about frying-pans that a typical buyer would not?
Keep what survives the data check. Drop the rest.
```

1. **The frying-pan equivalent of treadwear is the ply count ("3-ply", "5-ply", "7-ply").** It is on nearly every clad listing and in the existing add-on (`ply_count`), and it does not compare across brands. CenturyLife (verbatim): "Demeyere uses a 7-ply material for its skillets . That material is built like All-Clad (so it's 3-ply by All-Clad standards), but has an additional two layers of magnetic stainless steel on the bottom"; "The bottom line: The thickness of the heat-conductive layer is what helps spread heat evenly, not the number of layers. The number of plies doesn't matter." The Cookware Critic (verbatim): "The number of layers in a stainless steel pan does not determine how well it cooks. Total aluminum thickness and whether the pan is fully clad (aluminum running from base to rim) are what control heat distribution." **Kept** as a judgement (ply count does not compare across brands), as the `construction` facet (fully clad versus disc base, which is what does compare), and as a proposal to retire `ply_count` from the add-on. The same pattern applies to nonstick "layers" and "x times stronger" claims; Rational Kitchen (verbatim): "more expensive brands do tend to put more layers of nonstick coating on their pans ... in practice, we honestly haven't noticed a lot of difference". Kept inside the coating judgement, not as a facet.
2. **The watchmaker notices first what the polish hides: how much conductive metal there is and where it stops.** Two pans with the same mirror finish differ in millimetres of aluminium and in whether that aluminium runs up the sides. CenturyLife (verbatim) on disc bases: "The manufacturer then placed a thin, tapered stainless steel wrapper around the aluminum disc base. The wrapper disguises the discontinuity; customers can't see exactly where the disc ends." The watchmaker would also measure the floor rather than the rim (Made In lists a 12 in pan's cooking surface as 24.1 cm) and weigh the pan. **Kept**: `wall_thickness_mm` (researched, top N only), `construction`, `cooking_surface_diameter` and the floor-area derived metric, `weight_kg`. **Dropped**: flatness tolerance and warping resistance (no listing or reviewer publishes a figure; the only sourced claim is Cookware Critic's "Warping usually traces back to disc-bottom construction", kept inside `construction`), and handle attachment (CenturyLife prefers welds but "wouldn't reject a pan solely on the basis of having rivets"; it changes no pick).

## Sources and what each supports

### Regulators and standards

**FDA, Authorized Uses of PFAS in Food Contact Applications** (live page returned 404 to curl and the fetch tool; read from the Internet Archive snapshot of 2026-10-06, gzip-decoded)
https://www.fda.gov/food/process-contaminants-food/authorized-uses-pfas-food-contact-applications
- verbatim: "PFAS authorized for use in contact with food generally fall into four application categories: Nonstick coating applications; sealing gaskets for food processing equipment; manufacturing aids; and grease-proof agents for paper food packaging."
- verbatim (table row "Non-stick applications on pots & pans"): PFAS molecules "are then applied to the surface of the cookware at very high temperatures, which tightly binds the polymer coating to the cookware. ... Studies show negligible amounts of PFAS in this coating can migrate to food."
- Supports: PTFE coatings are FDA-authorised for food contact; FDA sees negligible migration. Confidence high.

**21 CFR 177.1550 Perfluorocarbon resins (eCFR)**
https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-177/subpart-B/section-177.1550
- verbatim: "Perfluorocarbon resins identified in this section may be safely used as articles or components of articles intended to contact food, subject to the provisions of this section"; identity includes "The homopolymerization and/or copolymerization of hexafluoropropylene and tetrafluoroethylene". PTFE is the homopolymer of tetrafluoroethylene.
- Supports: the US food-contact rule PTFE coatings sit under. Confidence high.

**Minnesota Statutes 116.943 (Amara's Law)**
https://www.revisor.mn.gov/statutes/cite/116.943
- verbatim: "(h) "Cookware" means durable houseware items used to prepare, dispense, or store food, foodstuffs, or beverages. Cookware includes but is not limited to pots, pans, skillets, grills..."
- verbatim: "Subd. 5. Prohibitions. (a) Beginning January 1, 2025, a person may not sell, offer for sale, or distribute for sale in this state the following products if the product contains intentionally added PFAS: ... (3) cookware;"
- verbatim: "(q) "Perfluoroalkyl and polyfluoroalkyl substances" or "PFAS" means a class of fluorinated organic chemicals containing at least one fully fluorinated carbon atom." PTFE meets this definition, so PTFE-coated pans fall under the ban.
- Supports: Minnesota sale ban from 1 January 2025. Primary statute; single source but the law itself. Confidence high.

**Maine Revised Statutes Title 38 §1614**
https://legislature.maine.gov/statutes/38/title38sec1614.html
- verbatim: ""Cookware product" means a durable houseware product intended to be used to prepare, dispense or store food ... including, but not limited to, a pot, pan, skillet, grill..."
- verbatim: "B-1. Except as provided pursuant to paragraph F or G , effective January 1, 2026, a person may not sell, offer for sale or distribute for sale in this State: ... (2) A cookware product containing intentionally added PFAS;"
- Supports: Maine sale ban from 1 January 2026. Primary statute; single source. Confidence high.

**California Attorney General, AB 1200 enforcement advisory, 17 October 2023 (PDF, pdftotext)**
https://oag.ca.gov/system/files/attachments/press-docs/AB1200%20Enforcement%20Advisory%20(1).pdf
- verbatim: "beginning January 1, 2023, a manufacturer of cookware subject to A.B. 1200's requirements shall post on the website for the cookware all of the following: 1. A list of all chemicals in the cookware that are also present on the designated list"
- verbatim: "beginning January 1, 2024, a manufacturer of cookware ... must list in the product label the intentionally added chemicals present on the "designated list" in the handle of the product or in any cookware surface that comes into contact with food"; "visible and legible to the consumer, including on the product listing for online sales."
- verbatim: a manufacturer "shall not claim ... that the cookware is free of any specific chemical if the chemical belongs to a chemical group or class identified on the designated list unless that chemical was not intentionally added".
- Supports: California requires chemical disclosure on cookware websites (2023) and labels and online listings (2024), which is why a PTFE disclosure can appear on listings; restricts "free of" claims. Confidence high.
- The California code pages (leginfo, Justia) returned 403 or a challenge page; not read.

### Specialist reviewers

**Consumer Reports, "You Can't Always Trust Claims on 'Non-Toxic' Cookware"**
https://www.consumerreports.org/toxic-chemicals-substances/you-cant-always-trust-claims-on-non-toxic-cookware-a4849321487/
- verbatim: "The PTFE-coated pan, on the other hand, had measurable amounts of PFOA and several other PFAS."; "we have decided to no longer display "PFOA-free" in our ratings of nonstick cookware. Such claims may not be reliable for PTFE-coated products."
- verbatim: "consumers who want to avoid PFAS in their nonstick cookware may want to focus on products that claim to be PTFE-free."; "An earlier study of 24 nonstick frying and baking pans she helped conduct concluded that pans with a PTFE-free label were indeed made with a ceramic coating." (Gillian Z Miller, Ecology Center)
- verbatim: "A California law that will go into effect in 2023 will ban companies from claiming in online sale listings that a cookware product is free of any one PFAS—like PFOA—if it contains any other PFAS, like PTFE. Those claims will have to be removed from packaging by 2024"
- verbatim: "our cookware tests show no noticeable differences in performance between the PTFE-free/ceramic pans and those with PTFE. In fact, they were neck-and-neck in our tests for cooking evenness and food release ... The only slight difference was in our durability test ... A few ceramic pans scored an Excellent on this test, while many of the PTFE pans scored that high."
- verbatim: "when PTFE coatings overheat, they can produce fumes that are deadly to small birds and may be harmful to humans as well."; "be sure not to scrape it with metal utensils or steel wool ... or preheat it when it's empty, which can cause it to overheat and release toxic fumes."
- Supports: PFOA-free is not a meaningful claim; PTFE-free means ceramic; ceramic equals PTFE on release, trails on durability; overheating risk. Confidence high.

**Consumer Reports, "5 Best Frying Pans If You Want to Avoid PFAS Chemicals"**
https://www.consumerreports.org/home-garden/cookware/best-frying-pans-if-you-want-to-avoid-pfas-chemicals-a1006253549/
- verbatim: "Nonstick frying pans outsell all other types by a considerable margin. They're easy to use, a cinch to clean, and inexpensive in many cases. But the nonstick coatings don't last forever. Most nonstick pans have to be replaced every few years and even sooner if they're scratched."
- verbatim: "there are several good alternatives, including ceramic , stainless steel , cast-iron , and carbon steel pans."; enamelled cast iron "can be used both on your cooktop and in the oven, even at very high heat"; "Cast iron can be heavy, though."
- Supports: nonstick is the largest segment and is a consumable; the surface families. Confidence high.

**The Rational Kitchen, "Ceramic Frying Pans: Are They Better than Teflon (PTFE)?"**
https://therationalkitchen.com/ceramic-frying-pans-better-than-teflon/
- verbatim: "The silicon material is heated to its melting point, then sprayed onto the cookware using a sol-gel process"
- verbatim: "At best, a nonstick ceramic frying pan has about the same life span as a PTFE frying pan. But in practice, ceramic nonstick seems to lose its slippery properties, on average, faster than PTFE nonstick does."; "If you decide to go with ceramic nonstick, know that it's something you'll probably be replacing every one-three years."
- verbatim: "high heat seems to do real damage to the nonstick properties"; "both require low-medium heat, hand washing, and plastic or wooden utensils"
- verbatim: "PTFE releases toxic fumes if heated above about 400F (the exact temp can vary by brand)." (Disagrees with the 260°C/500°F figure below; see judgements.)
- verbatim: "we recommend cast or forged aluminum bodies, both of which tend to be thicker than less expensive stamped aluminum"; "we do not recommend buying nonstick in clad stainless--the cooking surface will wear out decades before the rest of the pan does."
- verbatim: "Newer nonstick coatings can be reinforced with substances like titanium, diamond dust, granite, marble, and more. These are added to the nonstick coating--both PTFE and ceramic"
- verbatim: "The propellants in PAM break down PTFE and destroy it (never use aerosol cooking spray on a PTFE pan)." (Not used in the JSON.)
- Supports: ceramic wears faster; body under nonstick should be thick cast or forged aluminium; do not pay for clad under a coating; reinforcement names apply to both chemistries. Confidence medium (one reviewer's experience plus reading of owner reviews).

**The Cookware Critic, "Are Granite Stone Pans Worth It?"**
https://www.thecookwarecritic.com/reviews/are-granite-stone-pans-worth-it/
- verbatim: "The name suggests carved rock. The reality is a lightweight pressed-aluminum body coated in 3 layers of PTFE. That is the same polymer branded as Teflon, reinforced with mineral particles for the speckled look. The granite appearance is cosmetic ."
- verbatim: "Names like "diamond-infused" and "mineral-enforced" across different Granitestone product lines describe additives in the same PTFE base, not a fundamentally different cooking surface."
- verbatim: "food release for the first several months to about 2 years, depending entirely on how you use them."
- Supports: stone and diamond names can hide PTFE. Confidence medium (about one brand's lines).

**The Cookware Critic, "3-Ply vs 5-Ply Cookware: What Extra Layers Actually Do"**
https://www.thecookwarecritic.com/reviews/3-ply-vs-5-ply-cookware/
- verbatim: "The number of layers in a stainless steel pan does not determine how well it cooks. Total aluminum thickness and whether the pan is fully clad (aluminum running from base to rim) are what control heat distribution."
- verbatim: "According to NIST reference data, aluminum moves heat about 16 times faster than stainless steel (237 versus 14.9 watts per meter-kelvin)."
- verbatim: "The outer steel layer gives you durability and (when it uses 430 ferritic stainless) works on induction cooktops ."
- verbatim: "Check the rim. Visible distinct metal layers at the lip = fully clad."; "weight tells you more than the ply number printed on the box."
- verbatim: "Warping usually traces back to disc-bottom construction, not the number of plies."
- Supports: ply count noise; aluminium versus stainless conductivity; ferritic exterior for induction; rim check. Confidence medium-high (agrees with CenturyLife).

**CenturyLife.org (independent tester with micrometer and thermal-camera measurements; several articles)**
- "Thermal properties of metals" https://www.centurylife.org/thermal-properties-of-metals/
  - verbatim table: "Copper C11000 388-394"; "Aluminum (Pure) 237"; "Aluminum (3003-H14) 159-162"; "Iron (Cast) ~50-55"; "Carbon Steel (0.5 to 1% carbon) ~50-55"; "Stainless Steel (304) 16.2" (W/m-K at 20°C).
  - verbatim: "C11000 copper has about 2.3 times the conductivity of 3003/3004 aluminum alloy."; "you need about 2 mm of aluminum to match the performance of 1 mm of copper."
  - verbatim: "Lodge/Staub/Le Creuset are all about 4 mm thick ... a cheap, nonstick 2 mm aluminum pan should easily outperform even the most expensive cast iron or carbon steel when it comes to even heating!"
  - verbatim: "it is ludicrously easy to buy All-Clad or All-Clad knockoffs that have ~1.7 mm or less of aluminum conductive layer, but such thin layers of aluminum make for somewhat uneven heating ... in addition to other problems such as increased risk of warping"
  - verbatim: "I question the economic wisdom of paying premium prices for thick aluminum cookware that has PTFE coatings that may not last."
- "Cladded sidewalls vs. disc-bottomed cookware" https://www.centurylife.org/cladded-sidewalls-vs-disc-bottomed-cookware-which-is-better/
  - verbatim: "Your skillets/frying pans, saucieres, and woks should be cladded or else have sidewalls made from copper, aluminum, cast iron, or carbon steel."; "Saute pans benefit somewhat from cladding but it's less necessary than for skillets/saucieres/woks."
  - verbatim: "If you attempt to use disc-bottomed skillets/saucieres/woks, you will run into a temperature discontinuity where the disc ends and the thin steel sidewalls begin."
  - verbatim: "Demeyere figures that anything with vertical walls like saute pans, saucepans, and stock pots do not need conductive sidewalls ... In my experience, Demeyere is not entirely right."
  - verbatim: "induction stoves, which heat very unevenly, go with a thick disc-base construction because you will need every millimeter of aluminum or copper on the bottom that you can get." (said of saucepans and stockpots)
  - verbatim: "The wrapper disguises the discontinuity; customers can't see exactly where the disc ends. The disc base is significantly smaller in diameter than the diameter at the top of the cookware."
- "Cookware Thickness Database" https://www.centurylife.org/how-thick-is-insert-brand-cookware-how-thick-is-the-base-how-thick-is-the-clad-layer-where-was-it-made-is-it-induction-compatible-and-how-long-is-the-warranty/
  - verbatim rows (measured total wall, mm): "All-Clad D3 Stainless Clad 2.6"; "Calphalon Tri-Ply Stainless Clad 2.12"; "Cooks Standard Multi-Ply Clad Stainless Clad 2.44"; "Tramontina Tri-Ply Clad Clad 2.6"; "Demeyere Proline (skillet) Clad 4.76 4.8 3.7"; "Lodge Cast Iron Cast Iron 5.03 Fe (includes bumpiness)"; "Le Creuset enameled cast iron pan Cast Iron 3.68".
  - verbatim: "If we assume that everyone is using the same grade of aluminum/copper/thickness and the same thickness of stainless steel, then all else equal, the thicker cookware is more thermally conductive. Obviously those assumptions are shaky".
- "What's the difference between 3-ply and 5-ply and 7-ply" https://www.centurylife.org/what-is-the-difference-between-tri-ply-and-5-ply-and-7-ply-how-many-plies-do-i-need/ (quotes in Seed).
- "Heat retention myths and facts" https://www.centurylife.org/heat-retention-myths-and-facts-does-cast-iron-hold-heat-better-than-clad-is-clad-better-than-disc-base-at-retaining-heat-longer/
  - verbatim: "Cast iron is cheap, brittle, and conducts heat poorly, so many manufacturers make their cast iron 4 mm thick."; "As a rule of thumb, a 1 millimeter thick layer of cast iron or stainless steel holds about as much heat as a 1.5 millimeter thick layer of aluminum."; "All-Clad Stainless retains about the same amount of heat as 2mm of cast iron."
- "Cookware even heating rankings: induction and electric" https://www.centurylife.org/cookware-even-heating-rankings-induction-and-electric/
  - verbatim definition: "10 cm temperature delta means the temperature difference between the center of a pan and a 10 cm circle around the center, at the moment in time when the center of the pan reaches 350 degrees Fahrenheit".
  - verbatim rows (°F, lower is better): clad "92.6 Demeyere Proline 11 inch", "128.5 All-Clad D3 Stainless 12 inch", "146.1 Cooks Standard Multi-Ply Stainless 12 inch"; nonstick "28.1 Woll Diamond Plus Induction 11 Inch", "99.3 T-Fal Professional Total Nonstick 12 inch".
  - verbatim: "Pans advertised as 12 inches are typically 30 cm (11.81 inches) in diameter."
- "Rivets vs Welds" https://www.centurylife.org/rivets-vs-welds-should-i-buy-cookware-with-riveted-handles-or-welded-handles-what-about-screwed-on-handles/ (dropped facet; quote in Seed).
- Supports overall: construction, thickness, induction unevenness, the heating ranking as a visual grammar. Confidence medium-high: one careful tester with stated methods; the conductivity figures agree with Cooking for Engineers and the Cookware Critic except cast iron.

### Primers and academic

**Cooking for Engineers, "Common Materials of Cookware"**
https://www.cookingforengineers.com/article/120/Common-Materials-of-Cookware
- verbatim table: "Copper 401 W/m*K / Aluminum 237 W/m*K / Cast Iron 80 W/m*K / Carbon steel 51 W/m*K / Stainless steel 16 W/m*K".
- verbatim: "the heat capacity per unit volume of steel, cast iron, and copper are about 1.5 times that of aluminum. This means, to achieve the same heat capacity in an aluminum pan as in stainless steel pan, the aluminum pan needs to be 1.5 times as thick".
- verbatim: "both copper and aluminum react readily to foods"; "Carbon steel contains less carbon than cast iron and is formed and pressed from sheets instead of being casted."; "Because cast iron can react with acidic foods and ingredients that are cooked for a long time, cast iron cookware is seasoned".
- Supports: conductivity ladder (second source), heat-capacity rule, reactivity, carbon steel is pressed. Confidence high. Disagrees with CenturyLife on cast iron (80 versus 50 to 55).

**Wikipedia, Polytetrafluoroethylene**
https://en.wikipedia.org/wiki/Polytetrafluoroethylene
- verbatim: "While PTFE is stable at lower temperatures, it begins to deteriorate at temperatures of about 260 °C (500 °F), it decomposes above 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F)."
- verbatim: "PTFE-coated cookware is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between 204 and 232 °C (399 and 450 °F), and most cooking oils (except refined safflower and avocado oils) start to smoke before a temperature of 260 °C (500 °F) is reached."
- verbatim: "A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by PTFE cookware heated to 280 °C (536 °F) was lethal for parakeets".
- Supports: 260°C deterioration and the temperature scale grammar. Confidence high.

**Wikipedia, Polymer fume fever**: verbatim "an inhalation fever caused by the fumes released when polytetrafluoroethylene (PTFE, known under the trade name Teflon ) reaches temperatures of 300 to 450 °C (572 to 842 °F)." Supports vocabulary entry. https://en.wikipedia.org/wiki/Polymer_fume_fever

**Ghanem et al., "Influence of heating temperature and time on mechanical-degradation, microstructures and corrosion performances of Teflon/granite coated aluminum alloys used for non-stick cookware" (PMC11324993)**
https://pmc.ncbi.nlm.nih.gov/articles/PMC11324993/
- verbatim: "While PTFE is inert below 260 °C, exceeding this temperature can lead to the release of harmful fumes".
- verbatim: "three PTFE-coated aluminum pans and three ceramic (Granite) pans from different manufacturers (Manuf 1–6) were obtained." The paper treats "granite" pans as ceramic, which disagrees with the Cookware Critic.
- Supports: second source for 260°C; evidence that "granite" names both chemistries. Confidence medium (authors are not cited by name beyond the page header; I recorded the title).

**Wikipedia, Induction cooking**
https://en.wikipedia.org/wiki/Induction_cooking
- verbatim: "Typically, cookware must contain a ferromagnetic metal such as cast iron or some stainless steels ."; "Induction tops typically will not heat copper or aluminum cookware"; "Cookware should have a flat bottom since the magnetic field strength (heating power) drops rapidly with distance from the surface."; "Stainless steel pans are compatible if the base of the pan is a magnetic grade of stainless steel."; "If a magnet sticks well to the bottom of the pan, it is compatible."
- Supports: induction facet and the flat-bottom wok leg. Confidence high.

**Wikipedia, Frying pan**
https://en.wikipedia.org/wiki/Frying_pan
- verbatim: "It typically ranges from 20 to 30 cm (8 to 12 in) in diameter with relatively low sides that flare outwards, a long handle and no lid ."; "A pan of similar dimensions, but with less flared, more vertical sides and often with a lid, is called a sauté pan ."; "This pan is called a sauteuse ... an evasée ... or a fait-tout".
- Supports: shapes, size range, lid convention. Confidence high.

**Wikipedia, Seasoning (cookware)** and **Cast-iron cookware**
https://en.wikipedia.org/wiki/Seasoning_(cookware), https://en.wikipedia.org/wiki/Cast-iron_cookware
- verbatim: "Seasoning is the process of coating the surface of cookware with fat which is heated in order to produce a corrosion-resistant layer of polymerized fat."
- verbatim: "Tests conducted by America's Test Kitchen found that, while cooking a highly acidic tomato sauce for over 30 minutes produced a metallic taste, cooking acidic food in a well-seasoned pan for a short time is unlikely to have negative consequences."
- verbatim (cast iron): "Toxic heavy metals such as cadmium and lead can be leached from the enamel coating into food being cooked in some cast iron pots." (Not used in the JSON; no regulator source read.)
- Supports: seasoning definition, acid caveat. Confidence medium-high.

### Spec sheets (brand pages)

**All-Clad D3 12 in fry pan** https://www.all-clad.com/d3-stainless-3-ply-bonded-cookware-fry-pan-12-inch.html
- verbatim: "D3® Stainless is the original fully bonded tri-ply cookware"; "Our cookware is oven & broiler safe up to 600°F and compatible with any stovetop, including induction. Handwash Only."; spec table "Weight 3.000000", "Dimensions 20.1 x 12.5 x 4.4 inches", "Size 12 inch". Fields listed: model number, weight, made in, material, dimensions, exterior finish, colour, piece count, size, warranty, UPC.
- Supports: oven limit field, weight (3 lb for a 12 in clad pan), the fields brands list. No cooking-surface diameter.

**Made In Stainless Clad frying pan, 8, 10 and 12 in pages** https://madeincookware.com/products/stainless-steel-frying-pan/12-inch (and /10-inch, /8-inch)
- verbatim (12 in): "Total Diameter: 31.8 cm", "Depth: 4.4 cm", "Cooking Surface Diameter: 24.1 cm", "Weight: 1.36 kg". (10 in): "Total Diameter: 26.7 cm", "Cooking Surface Diameter: 19.1 cm", "Weight: 1.02 kg". (8 in): "Total Diameter: 21.6 cm", "Cooking Surface Diameter: 12.7 cm", "Weight: 0.79 kg".
- verbatim: "2.7mm Thick 5-Ply Construction"; "No bolted-on induction plates here. The outer layer of our clad body is ferritic stainless steel for induction performance."; "Heat Safe to 800°F (430°C)" in the header and "Heat Safe to 500°F (260°C)" in the Care block of the same page (inconsistent; recorded, not used).
- Supports: rim versus floor diameter, stated thickness, ferritic exterior, weights. The only brand page read that lists cooking-surface diameter.

**Lodge (Shopify product feed, lodgecastiron.com/products.json; product pages returned 404 to curl and the fetch tool)**
- 12 in seasoned cast iron skillet variants: variant weight field "grams 3583"; 10.25 in: "grams 2567". Carbon steel skillet: "8" grams 1066 / 10" grams 1583 / 12" grams 1882". Enamel skillet: "grams 2563" and verbatim "oven safe up to 500˚F". Carbon steel copy, verbatim: "Thin, lightweight carbon steel provides a quick, even heat"; "It comes seasoned and ready to use".
- The Shopify `grams` field is the weight the store ships by and may include packaging; treated as approximate.
- Supports: weight contrast between cast iron, carbon steel and clad; enamel oven limit.

**GreenPan (Shopify product feed)**: verbatim "The Thermolon™ 9G ceramic nonstick delivers effortless release"; page footer "*Our PFAS-Free Ceramic Nonstick is Made Without Intentionally Added PFAS". Supports: brands name the ceramic coating and the PFAS-free claim. https://www.greenpan.us/

**HexClad FAQ**: verbatim "Our cookware products use our proprietary HEXCLAD TerraBond™ ceramic nonstick coating, which is PTFE-free and PFAS-free." Supports: "hybrid" stainless-lattice pans are not a chemistry; this one is now ceramic. https://hexclad.com/pages/faq

### Could not reach

Serious Eats (all four skillet reviews: access block page from people.inc; no Wayback snapshot at the guessed URLs, and the Wayback CDX service went "Temporarily Offline"), America's Test Kitchen (search results only), Wirecutter (not attempted; earlier runs record nytimes.com blocks), EWG "Canaries in the Kitchen" (Cloudflare challenge, also in the archive copy), Chemours/Teflon consumer safety page (empty render), EUR-Lex Regulation 1935/2004 (empty response), California code text on leginfo and Justia (403), de Buyer product page (empty render), Lodge product pages (404), T-fal and GreenPan spec tables (rendered by script). Search excerpts from Healthline and others gave "500°F" as DuPont's own limit; not used because the page was not read. Amazon was not attempted.

## Data points used for derived metrics

- `floor_area_cm2` = π × (cooking_surface_diameter_cm / 2)². Made In 12 in: 24.1 cm floor → about 456 cm²; 10 in: 19.1 cm → about 287 cm²; 8 in: 12.7 cm → about 127 cm². So the 12 in pan has about 1.6 times the frying area of the 10 in, not the 1.44 times the rim figures (31.8 / 26.7 squared ≈ 1.42) suggest; and the 8 in pan has under half the 10 in's area.
- `floor_to_rim_ratio` = cooking_surface_diameter / rim diameter. Made In: 24.1 / 31.8 = 0.76; 19.1 / 26.7 = 0.72; 12.7 / 21.6 = 0.59. Sloped skillets sit lower than straight-sided sauté pans by definition (Wikipedia shapes), but I have no sauté-pan floor figure, so no band is given.
- `aluminium_equivalent_mm`: dropped from category.json 2026-10-25 (blind-check fix). The formula summed per-layer thickness × conductivity, but `depends_on` listed only the total `wall_thickness_mm`, `construction` and `surface_family`, none of which holds a per-layer thickness, so the metric could not be computed as declared. It also conflated cast iron (CenturyLife 50 to 55, CFE 80) and carbon steel (CFE 51) into one "50 to 80" constant that no single source gives for carbon steel. Constants, for the record if the metric is revived with a real layer-thickness input: aluminium alloy 160 W/m·K (CenturyLife; pure 237 in CFE and Cookware Critic), copper about 390 (CenturyLife 388 to 394; CFE 401), stainless 16 (CFE 16, CenturyLife 16.2, Cookware Critic 14.9), cast iron 50 to 80 (sources disagree: CenturyLife 50 to 55, CFE 80), carbon steel about 51 to 55 (CFE 51, CenturyLife ~50-55). CenturyLife's own worked figure: 4 mm cast iron ≈ 1.35 mm aluminium. A real fix would need a per-layer thickness facet, for example sourced from CenturyLife's "Est. Al. Thickness" column, which we did not add given the scope of this pass.

## Against the existing add-on schema

Field kinds from `zamana-expertise/AGENTS.md`: vertical anchor, category quality currency, hard filter, sizing (inside `sizing`, per variant), and high-signal markdown (everything else). Proposals only; nothing in zamana-expertise was edited.

| Register facet | Existing field | Proposed kind | Note |
|---|---|---|---|
| `surface_family` | `interior_cooking_surface` (add-on enum) and `materials[role=interior_surface/coating]` (kitchen standard) | Vertical anchor | Keep. The enum is finer than the split and maps onto it: ptfe_nonstick, ceramic_nonstick, nonstick_unspecified → nonstick coating; stainless_uncoated → stainless; bare_cast_iron_seasoned, carbon_steel_seasoned → seasoned iron or steel; enamel_interior → enamelled iron; tin_lined, anodized_uncoated, glass_ceramic, stone_clay_unglazed → other. |
| `coating_chemistry` | same enum (ptfe_nonstick / ceramic_nonstick / nonstick_unspecified) | Vertical anchor (part of it) | Keep, and add a resolution rule to the trap comment: resolve `nonstick_unspecified` to PTFE unless the page makes a PTFE-free claim (CR, Ecology Center). "Granite", "stone", "diamond", "titanium" and "hybrid" never decide it. California AB 1200 makes the "This product contains" line a reliable extraction target. |
| `induction_compatible` | `induction_compatible` | Hard filter | Keep. Augment when missing from material: cast iron, carbon steel and enamelled iron are always yes; bare aluminium and copper without a steel base are no. |
| `construction` | `body_construction` | Category quality currency | Keep the enum. It is the comparable signal the ply count pretends to be. |
| `wall_thickness_mm` | none | High-signal markdown | Few brands state it (Made In 2.7 mm); we would not happily augment it for every row, so by rule 4 it is not currency. Let Jev keep it when stated. |
| (seed) ply count | `ply_count` | Cut (noise) | Does not compare across brands (Demeyere 7-ply = All-Clad 3-ply by layer definition). Rule 5: curated claim, derivable noise. If kept, demote to markdown. |
| `diameter_in` | `sizing.diameter` | Sizing | Keep. Record the rim figure; note that inch labels are rounded from metric. |
| `cooking_surface_diameter` | none | Sizing (nullable) | Propose adding `sizing.cooking_surface_diameter`. It is the number experts compare and varies by size variant; Made In states it. Do not augment by guessing; null when absent. |
| depth | `sizing.depth` | Sizing | Keep; matters for sauté pans and woks. Not a register facet because no source gives a depth rule. |
| `weight_kg` | `sizing.weight` (supplies standard) | Sizing | Keep the standard field; no add-on duplicate needed. |
| `max_oven_temp` | `max_heat_temp` (kitchen standard) | Hard filter | Keep. Brand pages carry it (All-Clad 600°F, Lodge enamel 500°F). Watch pages that print two figures (Made In 800°F and 500°F). |
| `pan_shape` | none | Hard filter, but see rule 1 | The leaf bundles shapes, so an enum (skillet, sauté, sauteuse, wok, grill, crêpe or griddle, other) would be the leaf's anchor. Rule 1 says photo-answerable shape stays out; shape is also always in the title, so propose it as a title-derived enum or leave it to the image pipeline. Flagged for a decision. |
| `lid_included` | `pieces_included_text` (supplies standard) | Markdown / pieces text | No new field; the standard text field covers it. |
| `wok_bottom` | none | Image pipeline | Flat versus round is visible in photos (rule 1). No field. |
| — | `dishwasher_safe` (kitchen standard) | Keep in standard | Not a register facet: it follows from `surface_family` (seasoned iron never; coatings shortened by it; Rational Kitchen "hand washing"). |

Add-on fields this register considers noise: `ply_count` (above). Everything else in the add-on survives.

## Branches

Every leg is traced to a sentence in the register or above.

- surface_family = nonstick coating → ask `coating_chemistry`, `construction`. Chain for chemistry: the only claim that tells PTFE from ceramic is a PTFE-free claim (CR verbatim), and it decides the 260°C ceiling (Wikipedia, PMC) and the Minnesota and Maine bans. Construction: Rational Kitchen "cast or forged aluminum bodies ... thicker than less expensive stamped aluminum" and CenturyLife's measured evenness of thick aluminium nonstick (Woll 28.1°F delta).
- surface_family = stainless steel → ask `construction`, `wall_thickness_mm`; `coating_chemistry` irrelevant. Chain: a stainless cooking surface has no coating (definition in the register); stainless conducts at about 16 W/m·K so everything depends on the aluminium or copper inside (CFE, CenturyLife), on whether it runs up the sides (CenturyLife "skillets ... should be cladded") and on its thickness (CenturyLife "~1.7 mm or less ... somewhat uneven heating").
- surface_family = seasoned iron or steel → ask `weight_kg`, `construction`; `coating_chemistry` irrelevant. Chain: there is no coating on bare iron or steel; cast iron is cast and carbon steel is "formed and pressed from sheets" (CFE verbatim), but the answer "iron or steel" alone does not say which, so `construction` is asked, not inferred, to tell them apart (corrected 2026-10-25: the earlier version wrongly made `construction` irrelevant here). Weight is a second cue for the same split (Lodge 12 in cast iron about 3.6 kg against 12 in carbon steel about 1.9 kg; CR "Cast iron can be heavy").
- surface_family = enamelled iron → ask `weight_kg`; `coating_chemistry` and `construction` irrelevant. Chain: enamel is glass on cast iron (CFE), so it is cast and not a nonstick chemistry (CR lists enamelled cast iron among PFAS-free alternatives); weight as above (Lodge enamel skillet about 2.6 kg). `max_oven_temp` was dropped from this branch (corrected 2026-10-25): Lodge's 500°F enamel figure is one pan, and CR says enamelled cast iron can go "in the oven, even at very high heat", so no source shows enamel oven limits vary enough to change a pick.
- coating_chemistry = PTFE or not stated → ask `max_oven_temp`. Chain: PTFE "begins to deteriorate at temperatures of about 260 °C (500 °F)" (Wikipedia) and "is inert below 260 °C" (PMC), so the pan's stated heat limit is a safety number for this branch.
- pan_shape = frying pan or skillet → ask `construction`, `cooking_surface_diameter`; `wok_bottom` irrelevant. Chain: skillets need conductive sidewalls (CenturyLife verbatim); flared sides shrink the floor (Made In 12 in: 24.1 cm floor in a 31.8 cm rim). `lid_included` is no longer made irrelevant here (corrected 2026-10-25): Wikipedia's "no lid" describes the typical frying pan, not buyer indifference, and a skillet-with-lid is a common request, so lid filtering stays live on this branch.
- pan_shape = sauté pan → ask `lid_included`; `wok_bottom` irrelevant. Chain: sauté pans are "often with a lid" (Wikipedia). Construction is not made irrelevant, because CenturyLife disagrees with Demeyere that sauté pans can skip cladding.
- pan_shape = wok or stir-fry pan → ask `wok_bottom`, `construction`. Chain: flat bottom needed on induction and flat electric hobs (Wikipedia: "Cookware should have a flat bottom"); woks "should be cladded or else have sidewalls made from copper, aluminum, cast iron, or carbon steel" (CenturyLife). The lid leg is WEAK (some woks ship with lids) and was dropped: `lid_included` is not made irrelevant on the wok branch.
- induction_compatible = yes → ask `wall_thickness_mm`, `wok_bottom`. Re-sourced 2026-10-25: the earlier chain borrowed a CenturyLife sentence about saucepans and stockpots, which the blind check flagged as an unstated extrapolation to frying pans. Pan-specific evidence instead: CenturyLife's "Cookware Even Heating Rankings" page states "the pans tested below were tested on an induction cooker" and ranks 11-12 in skillets by the 10 cm temperature delta; thin tri-ply clad skillets (92.3 to 146.1°F) run far less even than thick aluminium nonstick skillets (28.1 to 99.3°F) on that test, which is the pan-specific case for a thick spreading layer under induction. Caveat kept for honesty: the page's table headers say "Electric" even though its own intro line says the pans were tested on an induction cooker, an inconsistency on the source site we could not resolve by re-reading it; we treat the intro line as authoritative. Round woks lose power off a flat glass top (Wikipedia). `wok_bottom` only matters if the shape answer was wok; see the induction/wok note below.
- induction_compatible = no: no branch is defined, and none should add one. A "no" answer does not distinguish a gas burner from a flat (radiant) electric cooktop, so it must not be read as "gas" for the purpose of filtering `wok_bottom`. Round woks are filtered out only by an explicit induction = yes answer; whenever the shape is wok, `wok_bottom` is asked directly on the `pan_shape` branch (see above) regardless of the induction answer, so a flat-electric buyer who says "no" to induction is not shown a round wok by default. Corrected 2026-10-25; `wok_bottom`'s own `why_experts_care` now states this limit.
- induction_compatible = no: no branch; the facet just stops filtering.

Dropped legs: "grill pan → ask ridge height" (no source); "crêpe pan → construction irrelevant" (no source); "nonstick → wall thickness irrelevant" (contradicted by CenturyLife's thick-aluminium nonstick measurements).

## Numbers in category.json and how many sources stand behind each

| Number | Sources |
|---|---|
| PTFE deteriorates from about 260°C (500°F) | Wikipedia PTFE (verbatim); PMC11324993 (verbatim). Rational Kitchen says about 400°F (disagrees, logged as a judgement). |
| PTFE decomposes above 350°C, pyrolysis above 400°C (scale grammar only) | Wikipedia PTFE (verbatim: "it decomposes above 350 °C ... pyrolysis occurs at temperatures above 400 °C"); PMC11324993 also gives both ("Temperatures beyond 350 °C result in smoke emission and, around 400 °C, trigger pyrolysis", per the blind check's re-read). Corrected 2026-10-25: this row previously called 350°C and 400°C single-source; two sources agree, so the figures stand, still only in the proposed temperature-scale grammar, never as a facet threshold. |
| Minnesota ban from 1 January 2025; Maine from 1 January 2026 | Each statute (primary, verbatim); single source each but the law itself. |
| California website disclosure 2023, label and online listing 2024 | AG advisory (verbatim); CR (verbatim). |
| Stainless about 16 W/m·K, aluminium 160 (alloy) to 237 (pure), so 10 to 16 times stainless (mechanism) | CFE 16 and 237; CenturyLife 16.2, 237 and 159 to 162; Cookware Critic 14.9 and 237. |
| Copper about 390 to 400 W/m·K | CFE 401; CenturyLife 388 to 394. |
| Cast iron 50 to 80 W/m·K, carbon steel about 51 | CenturyLife 50 to 55; CFE 80 (cast iron), 51 (carbon steel). Ranges stated as the disagreement. |
| 1 mm steel or iron holds as much heat as 1.5 mm aluminium | CFE (verbatim); CenturyLife (verbatim). |
| Frying pans 20 to 30 cm (8 to 12 in) | Wikipedia; Made In sells 8, 10 and 12 in. |
| Made In 12 / 10 / 8 in: floor 24.1 / 19.1 / 12.7 cm | Made In pages (brand-specific fact, stated as such). |
| Clad 12 in pan about 1.4 kg | Made In 1.36 kg; All-Clad 3 lb (1.36 kg). |
| Lodge 12 in cast iron about 3.6 kg; 12 in carbon steel about 1.9 kg; enamel skillet about 2.6 kg, 500°F | Lodge feed (brand-specific, stated as Lodge's figures). |
| All-Clad 600°F oven and broiler | All-Clad page (brand-specific). |
| Made In 2.7 mm 5-ply; CenturyLife tri-ply measurements 2.1 to 2.6 mm | Made In page; CenturyLife table. JSON says "most clad skillets measure under 3 mm in total" (both sources consistent). |

## Trimmed detail

- `coating_chemistry`: CR found 4 ppb PFOA and a combined 639 to 703 ppb of PFAS in a PTFE pan sold as PFOA-free; the ceramic pans tested contained none of 96 PFAS. The distributor disputed it. One test of one pan; not generalised in the JSON.
- `coating_chemistry`: AB 1200 also bars a "free of" claim for a chemical in a listed class unless that chemical was not intentionally added. Read literally, "PFOA-free" on a PTFE pan may still be allowed if PFOA was not intentionally added; CR reads it more strictly. The register does not rely on either reading, only on PTFE-free being the meaningful claim.
- `construction`: CenturyLife's evenness ranking (10 cm delta at 350°F, electric) puts thick aluminium nonstick (Woll 28.1°F, Anolon Nouvelle 46.5°F) ahead of every clad stainless pan (best 92.3°F) and thin tri-ply at 128.5 to 146.1°F. One tester; used as a visual grammar and in prose without the figures.
- `diameter_in`: CenturyLife says 12 in pans are typically 30 cm (11.81 in) and 11 in pans 28 cm; Made In's 12 in is 31.8 cm across the rim. Label sizes are rounded and measured inconsistently; that is why the floor diameter matters.
- `surface_family`: seasoning and acid. Wikipedia reports ATK found a metallic taste only after more than 30 minutes of tomato sauce; short acidic cooking is fine. Not a facet.
- `max_oven_temp`: corrected 2026-10-25. Re-fetched Made In's 12 in page: it now prints "Heat Safe to 800°F (430°C)" in both the header and the Care block, so the two-figure inconsistency this note recorded no longer holds. The "take the lower when two appear" extraction hint is kept anyway as a general guard against other brands' pages printing two different figures, but it is not illustrated by Made In any more.
- `wok_bottom`: "round ones are made for gas burners" is our wording of common practice, not a sourced sentence; the sourced part is Wikipedia's flat-bottom rule for induction.
- `pan_shape`: "designed for gentler cooking" paraphrases Wikipedia's "designed for lower-heat cooking".
- Enamel: Wikipedia says lead and cadmium can leach from some enamel; I read no regulator page (FDA's ceramicware lead guidance was not fetched), so it is not in the JSON.

## Corrections after the blind check (2026-10-25)

A blind checker (not the author) graded this register; their report is `check.md`. Every numbered item below answers one of its "Required fixes". Sources for the Colorado and Maine items were fetched fresh this run (curl into `scratchpad/fix-frying-pans/`, plus a direct fetch of Maine §1614(5)(G)); the CenturyLife, Made In and Wikipedia/PMC re-checks reused raw text already in that scratch folder from this session.

1. `max_oven_temp.backfill_note`: no longer tells the pipeline to show the 260°C PTFE deterioration onset as a pan's oven-safe rating when the maker gives none. The field is now left null in that case, and the coating limit stays a separate annotation in `why_experts_care`.
2. Regulatory coverage: added Colorado (SB24-081, cookware with intentionally added PFAS banned 1 Jan 2026, signed 1 May 2024; verbatim from leg.colorado.gov: "banning the sale or distribution of cleaning products that are not medical floor maintenance products, cookware, dental floss, menstruation products, and ski wax that contain intentionally added PFAS chemicals") to the MN/ME judgement, the `coating_chemistry` split rationale, its `skip_if_known` and its `backfill_note`, and added the `co_sb24_081` reference. Also added Maine's retailer-notification clause (§1614(5)(G): "The prohibitions in this subsection do not apply to a retailer ... unless the retailer ... has received a notification ... that the sale of the product is prohibited") to the `maine_1614` reference's `supports` and the judgement note.
3. `aluminium_equivalent_mm`: dropped from `derived_metrics`. Its declared `depends_on` (`wall_thickness_mm`, `construction`, `surface_family`) holds no per-layer thickness, so the per-layer formula could not be computed as written. Detail kept in notes.md in case a per-layer facet is added later.
4. `floor_to_rim_ratio`: restated the worked example to match the formula as written (nominal `diameter_in` in inches × 2.54), giving 0.79 for the 12 in Made In pan and 0.63 for the 8 in, replacing the old 0.76/0.59 figures that silently used the measured rim instead. Also edited `diameter_in.listing_field_hint` to say explicitly that the field records the labelled nominal size, not a tape measurement of the rim, since the two differ (Made In's "12 in" pan measures 31.8 cm; CenturyLife: 12 in pans "typically" measure about 30 cm).
5. `surface_family` branch "seasoned iron or steel": removed `construction` from `makes_irrelevant` and added it to `then_ask`. The answer "iron or steel" alone does not say cast or pressed, so construction has to be asked, not assumed; the "Branches" trace is corrected to match.
6. `induction_compatible = yes → wall_thickness_mm`: re-sourced with CenturyLife's pan-specific "Cookware Even Heating Rankings" page (its own line: "the pans tested below were tested on an induction cooker"), which ranks 11-12 in skillets and shows thin tri-ply clad running far less even (92.3-146.1°F delta) than thick aluminium nonstick (28.1-99.3°F) under that test, in place of the earlier quote about saucepans and stockpots. The "Branches" trace in notes.md records the extrapolation this replaces and a caveat about the source page's own inconsistent table labelling.
7. `pan_shape` branch "frying pan or skillet": removed `lid_included` from `makes_irrelevant`. A skillet-with-lid is a normal request; only `wok_bottom` stays irrelevant on this branch.
8. `surface_family` branch "enamelled iron": removed `max_oven_temp` from `then_ask`. One Lodge figure (500°F) does not show that enamel oven limits vary enough to change a pick; CR says enamelled cast iron tolerates "very high heat" generally.
9. `surface_family.skip_if_known`: removed "earlier answer: avoids PFAS", since avoiding PFAS does not decide the cooking surface (ceramic, stainless, iron and enamel are all PFAS-free). The equivalent rule already lives correctly on `coating_chemistry.skip_if_known` ("earlier answer: avoids PFAS or Teflon"), which is where it decides something.
10. Conductivity constants: resolved by dropping `aluminium_equivalent_mm` (item 3), which was the only place the register conflated cast iron and carbon steel into one "50 to 80" figure. The corrected constants (cast iron 50 to 80, sources disagree; carbon steel about 51 to 55) are kept in notes.md for any future revival of the metric.
11. `cooking_surface_diameter.backfill_cost`: raised from medium to high, and `backfill_note` now says to expect this field and both floor-dependent metrics null for most rows.
12. Scope: resolved the two-burner-griddle ownership loop with `cookware-stove-accessories` by claiming both single- and two-burner griddle plates here, since that sibling's own notes hand pans, woks and griddles back to `frying-pans`. Also stated the sauteuse/saucier boundary: a shallow sauteuse évasée is a sauté pan here; a deeper, rounder one belongs to `saucepans`.
13. Wok base vs. flat electric: `wok_bottom.why_experts_care` now says a "no" to the induction question does not distinguish gas from flat electric, so the facet should be asked whenever the shape is wok rather than inferred from the induction answer; the "Branches" trace spells out that `pan_shape`'s own branch already does this regardless of the induction answer.
14. Source labels: `lid_included.source` and `wok_bottom.source` changed from `researched` to `derived` (both are read off the title). `weight_kg.why_experts_care`, its `backfill_note`, and the cast-iron trade-off's `plain` text now say the Lodge figures come from the store's Shopify shipping-weight field and may include packaging.
15. Notes corrections: fixed the "Numbers in category.json" table row that called the PTFE 350°C/400°C thresholds single-source; PMC11324993 states both ("Temperatures beyond 350 °C result in smoke emission and, around 400 °C, trigger pyrolysis"), matching Wikipedia. Fixed the Made In two-figure note: a fresh fetch of its 12 in page now shows "Heat Safe to 800°F (430°C)" consistently in both the header and the Care block, so the earlier 800°F/500°F mismatch no longer holds. `surface_family.listing_field_hint` now maps "ceramic" (to nonstick coating, with ceramic chemistry) and "hybrid" lattice pans like HexClad (to nonstick coating, per HexClad's own FAQ: "PTFE-free and PFAS-free") explicitly.

No findings were rejected. Every item in check.md's "Required fixes" list is addressed above, each by one of the two options the check itself offered.

## Script problems

- `schema.json` restricts `vertical` to formulations, machines, fashion, furnishing, other. The brief asks for `vertical: "supplies"`, which the validator rejects ("'supplies' is not one of [...]"). category.json therefore carries `"vertical": "other"`, as most sibling Supplies registers written the same day do, so that validate, render and viewer run clean. Once the schema enum gains `supplies`, change that one field; nothing else depends on it.