Cast Iron Coatings
Cast iron is made from grey iron, a high-carbon ferritic metal alloy. Like most ferritic metals, grey iron is reactive with water and readily rusts. Cast iron is protected from corrosion with one of two coatings, oil seasoning and glass-enamel coating.
Enamel coatings are applied to cast iron as dry powder and are fused into a continuous coating in a high-temperature furnace. Enamels range from color to black and white, and from glossy to matte in appearance. The coating is very effective at protecting the underlying iron from corrosive reactions. Being glass, the coating is brittle and will chip and crack with heavy impact.
Oil seasoning is rubbed or sprayed onto ironware and baked. Baking causes the applied oil to polymerize. As the molecules in the oil cross-link they form a vegetable-oil-based coating that protects the underlying iron from exposure to corrosive substances. Seasoning forms a very thin protective layer. However, layers of seasoning can be built up on top of one another, forming a robust coating.
Oil seasoning has the added benefit non-stick cooking performance. A recent study has shown that this characteristic is not only beneficial when cooking but is also beneficial for food-safety; bacteria are inhibited from taking hold on the naturally non-stick surface.
Unlike tin, teflon, ceramic, and glass coatings, oil seasoning is easy to repair and renew, which is key reason why seasoned cast iron can last for generations.
Using New Cast Iron
Ironwood oil-seasoned products have been seasoned with cottonseed oil at the factory. Lightly clean your new cast iron before use with warm water and a mild detergent. Your new seasoned cast iron can be used as is, but it is always a good idea to apply additional seasoning to a new piece of seasoned cookware; it will improve the non-stick performance of the cookware and strengthen the factory coating.
Additionally, we recommend "breaking in" a new piece of seasoned ironware with simple baking and roasting recipes. Skillet pizzas are a fantastic way to break in a pan as are oven roasted potatoes. Both recipes involve coating the cooking surface of the ironware with oil and heating in the oven for an extended period of time, essentially seasoning the pan while cooking a dish!
When cooking coat your cooking surface with a cooking fat of your choice.
Always allow time for your cast iron to heat sufficiently before you begin to cook. Iron takes longer to reach cooking temperatures than aluminum and stainless steel cookware.
Allow cast iron to cool to a comfortable handling temperature before attempting to wash it. This makes handling safer and reduces the risk of thermal shock when cold water is introduced the a hot pan.
To clean, lightly scrub ironware with warm water using a stiff brush, bamboo wok scrubber, or smooth chainmail scrubber. Take care not to scratch the oil seasoning. Light detergent can be used but is not necessary. Immediately dry your ironware after rinsing.
Return the ironware to the cooktop and warm over medium heat. Apply a thin coating of oil to the cooking surface with a towel, wiping excess oil away to avoid pooling. Continue heating the pan until the oil begins to smoke, then remove the pan from the heat and allow to cool once more. It is best to use a high-smoke-point oil. Cottonseed, soy, and grape seed oil work very well. Applying a layer of seasoning after each use results in a very robust, and highly functional piece of cookware.
The oven and broiler can also be used for heating ironware when seasoning. Whatever the heat source is, use care when handling heated cookware.
Never store cast iron wet. Never store dried ironware in proximity to other wet dishes, cookware, or equipment. Even when seasoned, excessive and prolonged contact with water or other liquids will result in corrosion of the iron. Enthusiasts of cast iron will often store their pans on the cooktop or in the oven.
Avoid overheating empty ironware. Ironware is highly resistant to heat, but excessive heating can cause thermal shock causing ironware to crack.
A couple of times a year, oil should be applied to the entire piece of ironware. When seasoning the entire piece of cookware, it is best to use the oven. Set your oven to 450-500ºF. Rub oil oven the entire pan and remove any excess to avoid dripping and pooling. Place a baking sheet lined with aluminum foil on a bottom rack to catch any oil that drips off of the ironware. Place your ironware on a rack above the baking sheet. Bake for 45 minutes. Allow ironware to cool in the oven or on the cooktop, far out of reach. With the oven thoroughly pre-heated, consider making some pizza or baking a few loaves of bread!
If your seasoning is badly scratched or becomes delaminated from the underlying iron, it is advisable to apply several layers of oil in succession. To do this, simply use the stovetop or oven methods listed above, repeating sequence of steps 2 to 3 times.
If your ironware is subjected to a corrosive environment or corrosive elements, it may be necessary to strip the ironware of its seasoning entirely with an abrasive.
Small amounts of light rust can be scrubbed away with steel wool or an abrasive pad. Once the light rust is loosened from the surface it can be rinsed away. Dry the ironware immediately and proceed to applying 2 to 3 layers of oil seasoning.
Heavy corrosion can be removed through abrasive processes. Because iron pans are typically irregular in shape, they are difficult to clamp or otherwise secure. For this reason, we do not advise the use of power sanding, grinding, or wire-brushing with power tools. If power tools are used to repair corrosion damage, be sure to wear eye, ear, hand, and body protection.
Abrasive sand-blasting is the best process to use in corrosion damage repair. Most welding shops, machine shops, and auto body shops have a small sand-blasting cabinet. It takes 15-30 minutes to sand-blast an entire pan, restoring it to a shiny silver appearance. Raw iron must be seasoned immediately to avoid new oxidization. Avoid touching raw iron with bare hands as this can cause corrosive reactions with the iron.
Cast Iron requires regular maintenance. But the steps are easy and take very little time. The payoff for this routine care is cookware that will last for generations.
For simplified cleaning and maintaining instructions, click here.