Glossary

Navigating the world of cast iron cookware, seasoning, and maintenance can be confusing. The Iron Patina has compiled this comprehensive glossary to help beginners and experts alike understand the terminology used in our guides and documentation.

A

Abrasive Media: Definition: Tools and materials such as steel wool, chainmail scrubbers, scouring pads, and sandpaper used to remove rust or failed seasoning. Choosing the correct grit and technique minimizes unnecessary metal removal.
Context: Used during restoration or resurfacing.
Acidic Foods: Definition: Ingredients high in acid (e.g., tomatoes, vinegar, wine) that can strip immature seasoning and cause metallic flavors. Well-built seasoning resists brief exposure, but prolonged simmering or soaking is not advised.
Context: Seasoning durability and care.
Alligatoring: Definition: A cracked, scaly appearance of the seasoning caused by overly thick coats or uneven polymerization. It often leads to flaking and benefits from spot-correction or a full strip-and-reseason approach.
See also: Thin Coat; Spalling.

B

Base Oil: Definition: The primary oil chosen to build seasoning layers. Oils with higher unsaturation (drying/semi-drying) generally polymerize more readily under oven heat.
Context: Seasoning selection.
Black Rust (Magnetite): Definition: A stable black iron oxide (Fe3O4) that can form under reducing conditions or after electrolysis. It adheres better than red rust and can serve as a conversion layer beneath seasoning.
See also: Ferric Oxide (Red Rust); Electrolysis.
Burn-off Cycle: Definition: A high-heat cleaning method (e.g., self-clean oven) that carbonizes old buildup. It can produce heavy fumes, accelerate oxidation, and risk warping; use with caution.
Context: Restoration method, last resort.

C

Carbonization: Definition: Thermal decomposition of oils into carbon-rich residue when heated past their smoke point. Controlled carbonization contributes to the dark color of seasoning, but excessive carbonization can cause brittleness.
See also: Polymerization; Smoke Point.
Chainmail Scrubber: Definition: A mesh of stainless-steel rings used to remove stuck-on debris without aggressively stripping polymerized seasoning. It is durable, easy to rinse, and effective when used with hot water.
Context: Routine cleaning.
Cure Cycle: Definition: The time-temperature schedule used to polymerize a thin coat of oil into a hard film. Typical oven cycles fall in the 400–500°F (205–260°C) range with full cool-down between coats.
See also: Thin Coat; Oven Polymerization.

D

Degreasing: Definition: Removing manufacturing waxes, cooking residues, and oils using hot water, detergents, or alkaline solutions. Proper degreasing ensures new seasoning adheres uniformly.
Context: Pre-seasoning preparation.
Drying Oil: Definition: An oil high in polyunsaturated fatty acids that oxidatively cross-links into a hard film when heated thinly (e.g., flaxseed, perilla, walnut). Drying oils can build robust seasoning but must be applied in very thin coats to avoid stickiness.
See also: Polymerization; Thin Coat.
Ductile Iron: Definition: Cast iron containing nodular graphite that improves toughness compared with gray iron. While common in industrial parts, cookware is usually made from gray iron for its castability and thermal characteristics.
Context: Material distinctions.

E

Electrolysis (E-Tank): Definition: A rust-removal process using a DC power source, a sacrificial anode, and a washing-soda electrolyte to reduce red rust to black oxide. It preserves base metal and is effective on heavy corrosion when used safely and properly ventilated.
See also: Black Rust; Ferric Oxide (Red Rust).
Enamel: Definition: A vitreous glass coating fused to cast iron for a non-reactive, easy-to-clean surface. It eliminates oil-based seasoning needs but is vulnerable to chipping and thermal shock.
Context: Coating technology.
Etching: Definition: Chemical roughening of iron by acids, which increases surface area for mechanical adhesion of seasoning. Uncontrolled etching can leave a dull, over-etched surface that requires care to recondition.
See also: Vinegar Bath; Neutralization.

F

Factory Seasoning: Definition: Pre-applied protective and functional oil coating from the manufacturer. Quality varies; many users still perform additional thin coats to optimize nonstick performance.
Context: New-pan preparation.
Ferric Oxide (Red Rust): Definition: The common red oxide (Fe2O3) indicating active corrosion that undermines seasoning. It should be removed promptly via mechanical means, electrolysis, or careful acid treatment.
See also: Black Rust; Rust Bloom.
Flash Rust: Definition: Rapid, light rusting that forms on freshly stripped or wet bare iron as it dries. Immediate drying and a thin protective oil film prevent it.
Context: Post-wash handling.

G

Gate Grind: Definition: The ground area where molten iron entered the mold, often visible as a small flat or “nib.” It is cosmetic but may need smoothing if it creates a snag point.
Context: Casting artifact.
Graphite (in Gray Iron): Definition: Flake graphite within gray cast iron that contributes to heat retention and natural lubricity. It also reduces ductility, making the material more brittle than steel.
Context: Material microstructure.
Grit (Abrasive Rating): Definition: A measure of abrasive particle size used for sanding or lapping; lower numbers are coarser. Typical resurfacing might start around 80–120 grit and finish 180–220+ for a smoother feel.
See also: Lapping; Abrasive Media.

H

Heat Diffuser: Definition: A metal plate placed between a burner and pan to moderate heat and distribute it more evenly. It helps prevent hot spots and scorching on thin or high-output burners.
Context: Stove-top control.
Helper Handle: Definition: A secondary small handle opposite the main handle to assist with lifting heavy cookware. Always use dry, heat-safe protection to avoid steam burns.
Context: Safe handling.
Hot Spot: Definition: A localized area of higher temperature on the cooking surface due to burner pattern, pan geometry, or uneven contact. Managing burner size and preheat time reduces hot spots.
See also: Heat Diffuser; Warp.

I

Induction Compatibility: Definition: Cast iron is ferromagnetic and generally works well on induction cooktops. Flat, smooth contact improves efficiency and reduces noise.
Context: Cooktop selection.
Inclusions: Definition: Non-metallic particles (e.g., sand or slag) trapped in the iron during casting that can appear as pits or hard spots. Minor inclusions are cosmetic; severe cases may require resurfacing or return.
Context: Casting quality.
Initial Seasoning: Definition: The first set of thin, high-heat oil coats applied to bare or stripped cast iron. It establishes the base film for ongoing maintenance layers.
See also: Cure Cycle; Thin Coat.

J

J-Hook: Definition: A hook shaped like the letter “J” used to hang skillets by their handle eye for storage and drying. Hanging promotes airflow and reduces moisture accumulation.
Context: Storage practice.
Joint Line (Parting Line): Definition: The seam where the two halves of a sand mold met, often visible as a raised line. It may be lightly ground at the foundry and is mostly cosmetic.
See also: Gate Grind.
Jig (Lapping Jig): Definition: A simple fixture that holds the pan steady and square while resurfacing or polishing the cooking surface. A jig improves consistency and helps maintain flatness.
Context: DIY resurfacing.

K

Kettle (Bail-Handle Dutch Oven): Definition: A deep cast iron vessel with a wire bail for lifting and hanging, often used outdoors. Maintenance parallels skillets: dry thoroughly and oil lightly after use.
Context: Cookware form factor.
Kosher Salt Scrub: Definition: A gentle abrasive cleaning method using coarse salt with a little warm water or oil to lift stuck-on residue. It preserves seasoning while smoothing rough patches.
See also: Chainmail Scrubber; Scouring Pad.
Knob (Lid Knob): Definition: The handle on a lid, which should be heat-rated to your cooking temperatures. Metal knobs tolerate higher oven temperatures than many polymer knobs.
Context: Lid hardware considerations.

L

Lapping: Definition: Manual or machine-assisted smoothing of the cooking surface using abrasives. It can reduce stickiness by lowering peak roughness but removes material and is optional.
See also: Grit; Machined Finish.
Lid Basting Dimples: Definition: Raised bumps on the underside of a lid designed to condense and redistribute steam. They do not affect seasoning directly but require thorough drying to prevent rust.
Context: Lid maintenance.
Lye Bath: Definition: An alkaline stripping solution (sodium hydroxide) that dissolves organic residues and failed seasoning without attacking base iron. It does not remove rust and requires careful handling and PPE.
See also: Degreasing; Electrolysis.

M

Machined Finish: Definition: A factory-milled or ground surface that is smoother than as-cast. Machining can improve release with less seasoning but may slightly reduce thickness.
Context: Surface texture.
Mineral Oil (Food-Grade): Definition: A non-drying, food-safe oil often used for short-term rust protection during storage. It is not suitable for building seasoning because it does not polymerize into a hard film.
See also: Drying Oil; Wipe-Down.
Microcracking (Seasoning): Definition: Fine, microscopic fissures that develop in polymerized oil films due to thermal cycling. Normal use fills them with additional polymerized oils over time.
Context: Natural wear-in of the coating.

N

Neutralization: Definition: The process of stopping acid action (e.g., after a vinegar bath) with a basic rinse such as baking soda solution, followed by thorough freshwater rinsing. It prevents continued etching and protects the iron.
Context: Post-acid treatment step.
Nitrile Gloves: Definition: Chemical-resistant gloves used to protect skin from lye, solvents, and oils during restoration and seasoning. They maintain dexterity while improving safety.
Context: PPE/handling.
Nonstick Effect (Seasoned): Definition: The release behavior created by a well-built polymerized oil film coupled with appropriate heat and technique. It is not the same as PTFE; it improves with use and care.
See also: Seasoning; Polymerization.

O

Oil Smoke Point: Definition: The temperature at which an oil starts to smoke and break down. For seasoning, choose an application temperature that promotes polymerization without excessive soot formation.
Context: Temperature control.
Oven Polymerization: Definition: Oxidative cross-linking of unsaturated fats into a solid film when heated in thin layers with oxygen present. Even, controlled oven cycles build durable seasoning.
See also: Cure Cycle; Thin Coat.
Oxidation: Definition: Chemical reaction of iron with oxygen and moisture that produces rust. Managing moisture, heat, and protective oil films reduces oxidation risk.
Context: Corrosion fundamentals.

P

Patina: Definition: The dark, layered seasoning that develops over time through repeated thin coats and use. A mature patina enhances release and corrosion resistance.
See also: Seasoning; Re-Seasoning.
Pitting: Definition: Localized corrosion cavities in the iron surface caused by rust or aggressive chemicals. Shallow pits can be filled gradually with seasoning; deep pits may require resurfacing.
Context: Restoration assessment.
Polymerization: Definition: The chemical process where heat and oxygen convert unsaturated oils into a cross-linked, hard film on iron. Proper polymerization depends on thin application, clean surfaces, and adequate temperature.
See also: Drying Oil; Oven Polymerization.

Q

Quench: Definition: Rapid cooling of hot metal, typically in liquid. Quenching hot cast iron can induce thermal shock and cracking; allow cookware to cool gradually.
Context: Thermal safety.
Quick Season: Definition: A maintenance step using a very thin oil coat and short stovetop or oven heat to refresh release between full cure cycles. It is useful after light abrasive cleaning.
See also: Wipe-Down; Thin Coat.
Quarter-Turn Wipe: Definition: A wiping technique where you rotate the cloth periodically to present a clean face, preventing excess oil and lint. It helps achieve an ultra-thin, even film.
Context: Application technique.

R

Re-Seasoning: Definition: Reapplying seasoning layers after partial or full stripping, or when performance declines. The process mirrors initial seasoning with emphasis on cleanliness and thin coats.
See also: Degreasing; Cure Cycle.
Ring Test: Definition: A simple acoustic check where gently tapping the pan produces a clear ring; a dull thud can indicate cracks or defects. It is not definitive but can guide further inspection.
Context: Condition assessment.
Rust Bloom: Definition: Early-stage, spotty orange rust that appears after moisture exposure. It is best addressed immediately with light abrasion, thorough drying, and a protective oil wipe.
Context: Preventive maintenance.

S

Seasoning: Definition: The hard, polymerized oil film bonded to cast iron that provides release and rust protection. Built from multiple thin coats, it strengthens with use.
See also: Patina; Polymerization.
Soap Use: Definition: Modern mild dish soaps do not dissolve fully cured seasoning but can remove surface oils. Rinse and dry thoroughly, then apply a light protective oil if desired.
Context: Cleaning practice.
Spalling: Definition: Flaking or delamination of seasoning due to over-thick application, trapped moisture, or thermal shock. Remove loose areas, clean, and rebuild with thin coats.
See also: Alligatoring; Thin Coat.

T

Thermal Mass: Definition: The heat capacity of the pan, driven by thickness and material, which stabilizes temperature. Cast iron’s high thermal mass benefits searing consistency but requires longer preheat.
Context: Heat behavior.
Thermal Shock: Definition: Stress from rapid temperature change that can crack enamel or, rarely, bare cast iron. Avoid adding cold liquids to very hot cookware or quenching a hot pan.
Context: Handling caution.
Thin Coat: Definition: A minimal oil application that leaves no visible pooling or streaks after wipe-down. It is essential for even polymerization and durable seasoning.
See also: Cure Cycle; Quick Season.

U

Ultra-Fine Steel Wool (#0000): Definition: A very fine abrasive used for gentle rust removal, smoothing, or between-coat touch-ups. It should be followed by thorough cleaning to remove residue.
Context: Light restoration.
Under-Seasoned: Definition: A condition where the film is too thin or immature to provide reliable release and rust protection. Additional thin coats and proper use will improve performance.
See also: Initial Seasoning; Patina.
Uncoated Cast Iron: Definition: Bare cast iron without enamel that relies on oil-based seasoning for protection and release. It offers high durability with proper care.
Context: Cookware category.

V

Vegetable Oil: Definition: A broad category of plant-derived oils used for seasoning and protection. Different oils vary in unsaturation and smoke point, affecting polymerization quality.
See also: Drying Oil; Oil Smoke Point.
Vinegar Bath: Definition: A controlled acetic acid soak to dissolve rust from bare iron. It must be monitored closely and neutralized to prevent over-etching.
See also: Neutralization; Etching.
Vitreous Enamel: Definition: A glassy, fused coating synonymous with porcelain enamel. It is non-porous and corrosion-resistant but susceptible to chipping if abused.
Context: Coating type.

W

Warp: Definition: Permanent distortion of the cooking surface or base, typically from uneven heating or thin sections. Minor warp can be managed with technique; severe warp affects stability and contact.
Context: Flatness and heat distribution.
Wax Coating (Shipping Wax): Definition: A protective wax or polymer coating applied at the factory to prevent rust during shipping. It must be fully removed before initial seasoning.
See also: Degreasing; Initial Seasoning.
Wipe-Down: Definition: The final cloth pass that removes excess oil and leaves only a whisper-thin film. Proper wipe-down prevents sticky or streaky seasoning.
Context: Application technique.

X

XRF Analysis: Definition: X-ray fluorescence used to non-destructively characterize the elemental composition of cast iron. It is occasionally used to verify alloy content or contaminants.
Context: Material testing.
XPS Pattern Casting: Definition: Casting with expanded polystyrene patterns (lost-foam) that vaporize when poured, capturing intricate shapes. It is uncommon for cookware but relevant to broader casting methods.
Context: Manufacturing process.
Xylene (Not Recommended): Definition: A strong organic solvent sometimes used industrially to remove coatings. It is not food-safe and should not be used on cookware intended for kitchen use.
Context: Safety advisory.

Y

Yield Strength: Definition: The stress at which a material begins to deform plastically; cast iron has low tensile ductility and relies on compressive strength. Practical takeaway: avoid impacts and thermal shock.
Context: Material behavior.
Yellowing (Seasoning): Definition: A light amber or yellow tint indicating an early-stage or inadequately cured oil film. Additional thin coats and proper heat will darken and strengthen it.
See also: Under-Seasoned; Cure Cycle.
Yoke (Bail Yoke): Definition: The metal arms attaching a wire bail to a kettle or camp oven. Keep the yoke clean and dry to prevent hidden rust at pivot points.
Context: Hardware maintenance.

Z

Zinc-Plated Hardware (Caution): Definition: Screws, racks, or fasteners coated with zinc that can off-gas at high temperatures. Do not use zinc-plated racks during high-heat burn-off or curing cycles.
Context: Safety and ventilation.
Zirconia Abrasive: Definition: A durable abrasive grain used in sanding discs and belts for efficient metal removal. Useful for heavy resurfacing when controlled carefully to preserve flatness.
See also: Grit; Lapping.
Zero-VOC Degreaser: Definition: A cleaner formulated without volatile organic compounds to reduce fumes while removing oils. Ensure it is food-contact safe and rinse thoroughly.
Context: Pre-seasoning cleaning.

Questions about cast iron care or a term we missed? Contact The Iron Patina at https://ironpatina.com/contact-us/.