Seasoning a pan
A seasoned pan has a stick-resistant coating consisting of polymerized fat and oil on the surface. Typically seasoned pans are cast-iron cookware and carbon steel cookware, in which case seasoning is desired. When seasoned, an iron or carbon steel pan is protected so that the bare cookware does not rust. For other pans e.g., stainless, aluminum, enameled), the same chemical phenomenon can occur, but seasoning may not be desired because it makes a pan look splotchy, or the pan may already have stick-resistant qualities.
Surface chemistry
When oils or fats are heated in a pan, multiple degradation reactions occur, including: autoxidation, thermal oxidation, polymerization, cyclization and fission.[1][2]
The process of heating a pan to cause the oil to oxidize is analogous to the hardening of drying oil used in oil paints, or to varnish a painting. See drying oil for details of the chemistry of the drying process. But whereas the curing of oils is the result of autoxidation at room temperature for a painting, for a pan, the thermoxidized oil undergoes a conversion into the hard surface of the seasoned pan at the high temperatures of cooking.
Heating the cookware (such as in a hot oven or on a stovetop) facilitates the oxidation of the iron; the fats and/or oils protect the metal from contact with the air during the reaction, which would cause rust to form. Some cast iron users advocate heating the pan slightly before applying the fat or oil to ensure that the pan is completely dry and to open "the pores" of the pan.[3][4]
Methods of creation
A metal (not a nonstick) pan will develop a seasoned coating over the course of typical cooking, if it is not scrubbed down to bare metal between cleaning. It is a natural by-product of using the cookware to cook foods that deposit oils or fats on the pan. This coating is initially a clear brown, but will darken to after prolonged use to be more glossy and dark brown or black.[5]. Fats and oils typically used for seasoning include lard, hydrogenated cooking oils such as Crisco, and palm or coconut oil (in general, oils that are high in saturated fats). Often seasoning is uneven in a pan, and over time the distribution will spread to a whole pan.
A new pan (bare metal) is porous and will grab food tightly, and must either be oiled before cooking or seasoned. To season a pan (e.g., to season a new pan, or to replace damaged seasoning on an old pan), the following is a typical process: (a) cleaning the cookware to expose the bare metal, (b) applying a layer of animal fat or vegetable oil, and (c) heating the cookware to generate the seasoned coating.[6][7][8] If it is not pre-seasoned, a new cast iron skillet or dutch oven typically comes from the manufacturer with a protective coating of wax or shellac, otherwise it would be rusted. This must be removed before the oven is used.[9] An initial scouring with hot soapy water will usually remove the protective coating. Alternatively, for woks, it is common to burn off the coating over high heat (outside or under a vent hood) to expose the bare metal surface. For already-used pans that are to be re-seasoned, the cleaning process can be more complex, involving rust removal and deep cleaning (with strong soap or lye,[10] or by burning in a campfire or self-cleaning oven)[11] to remove existing seasoning and build-up.
A damaged pan can be reseasoned by stripping the pan down to bare metal, and re-seasoning.
Care
As with other cast iron vessels, a seasoned pan or dutch oven should not be used to cook foods containing tomatoes, vinegar or other acidic ingredients. These foods will damage the new seasoning. Instead, newly seasoned ovens should be used to cook food high in oil or fat, such as chicken, bacon, or sausage, or used for deep frying. Subsequent cleanings are usually accomplished without the use of soap. Because modern cleaning methods (detergent soaps, dishwashers) will destroy the seasoning on cast iron, manufacturers and cookbook authors recommend only wiping the pans clean after each use, or using other cleaning methods such as a salt scrub or boiling water, [12]
Other surface types
There are other surfaces on cookware which are stick-resistant. See also Non-stick_pans.
In the process of bluing (steel), there is formed an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe3O4), the black oxide of iron (as opposed to rust, the red oxide of iron (Fe2O3)). Black oxide provides minimal protection against corrosion, however, unless also treated with a water-displacing oil to reduce wetting and galvanic action.
Related pages
References
- ^ Chang, S. S., Peterson, R. J. & Ho, C. T. (1978) Chemical reactions involved in the deep-fat frying of foods. J. Am. Oil Chem. Soc. 55: 718–727.
- ^ Paul, S. & Mittal, G. S. (1997) Regulating the use of degraded oil/fat in deep-fat/oil food frying. Crit. Rev. Food Sci. Nutr. 37: 635–662.
- ^ "Seasoning Cast Iron". Retrieved 2008-01-03.
- ^ "Cooking Louisiana - Seasoning Cast Iron Pots". Retrieved 2007-12-31.
- ^ "Home seasoning your Lodge cast iron cookware". Retrieved 2008-01-03.
- ^ "Home seasoning your Lodge cast iron cookware". Retrieved 2009-02-16.
- ^ "Care and seasoning of your wok". Retrieved 2008-01-03.
- ^ "Seasoning Frying Pans".
- ^ "Care of Cast Iron Pots and Pans". Retrieved 2008-01-03.
- ^ "Cleaning Cast Iron With Lye". Retrieved 2008-01-03.
- ^ "How to use your self-cleaning oven for cleaning cast iron". Retrieved 2008-01-03.
- ^ Emery, Carla (2003). The Encyclopedia of Country Living: An Old Fashioned Recipe Book. Sasquatch Books. p. 41. ISBN 157061377X.
External links
- How to season bare cast iron cookware from Lodge
- Seasoning cast iron from the Kitchen Emporium.
- HOW TO SEASON A NEW BLACK POT from Chef John Folse.
- THE SCOOP ON SEASONING, CLEANING AND RESTORING CAST IRON from Melinda Lee
- Cast Iron Cooking, from Holiday Cook