Seasoning
(cookware)
From Wikipedia, the free encyclopedia
Seasoning is the process of treating the surface of a saucepan, wok, crepe griddle or other cooking vessel with a stick-resistant
coating formed from polymerized fat and oil on the surface.
Seasoning is desirable on cast-iron cookware and carbon steel
cookware, because otherwise they are very sticky to foods and rust-prone. It
is generally not desired on other types of cookware either for cosmetic reasons
or because the chemical composition of the pan already results in a non-stick
surface.[citation needed]
Methods
of seasoning
A new pan (bare metal) is porous[citation needed] and will grab
food tightly, and must either be oiled before cooking or seasoned. This base
coat is initially created by a process of layering a very thin coat of oil on
the pan. Then, the oil is polymerized to the metal's surface with high heat for
a duration. The base coat will eventually develop a more refined coating
through use, e.g., frying or searing, and darken over time. This entire process
is known as "seasoning". The colour of the coating is commonly known
as its "patina".
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 thin layer of animal fat
or vegetable oil, and (c) heating the cookware to generate the seasoned
coating.[1][2][3]
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 item is used.[4]
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,[5]
or by burning in a campfire or self-cleaning oven)[6]
to remove existing seasoning and build-up. Once the pan has been heated, dried,
and thinly layered with oil or fat, it is placed in an oven, grill, or other
heating enclosure for the oil to be polymerized onto the metal's surface. The
process of polymerization is dependent on the oil, temperature of the
enclosure, and the duration. The precise details of the seasoning process
differ from one source to another, and there is much controversy regarding the
correct oil to use. There is also no clear consensus with the correct temperature
and duration. Lodge Manufacturing uses a proprietary soybean blend in their base coats as
stated on their website. Others use lard, or animal fats. Some advocate the use
of food-grade flaxseed oil (a drying oil).[7]
Likewise, the recommended temperature for seasoning varies to high temperatures
above 260 °C (500 °F), while some recommend a lower temp below
150 °C (302 °F). Some say that a temperature around the smoke point
of the oil or fat should be targeted since this will allow vaporization of
impurities from the oil, and polymerization and carbonization to occur. And,
there is also no clear determination of the correct duration of heat to use.
Anywhere from half an hour to an hour is often recommended.
Seasoning a cast iron or carbon
steel wok is a
common process in Asia and Asian-American culture. While the vegetable oil
method of seasoning is also used in Asia, a traditional process for seasoning
includes the use of Chinese chives or scallions as part of the process.[8]
Surface
chemistry
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. 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.
When oils or fats are heated in a
pan, multiple degradation reactions occur, including: autoxidation,
thermal oxidation, polymerization,
cyclization
and fission.[9][10]
Often seasoning is uneven in a pan, and over time the distribution will spread
to a whole pan. 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.[11][12]
The surface is hydrophobic, and oils or fats for cooking will spread evenly. The
seasoned surface will deteriorate at the temperature where the polymers break
down. This is not the same as the smoke point of the original oils and fats
used to season the pan because those oils and fats are transformed into the
plasticized surface. (This is analogous to how the smoke point for crude oil
and plastic are different).
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.[citation
needed] 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.[13]
Other
surface types
In the process of bluing, an
oxidizing chemical reaction on an iron surface selectively forms magnetite
(Fe3O4), the black oxide of iron
(as opposed to rust, the red
oxide of iron (Fe2O3)). Black oxide provides minimal
protection against corrosion if also treated with a water-displacing oil to
reduce wetting and galvanic action.
The entire wiki article, with images and references, can be
found at: http://en.wikipedia.org/wiki/Seasoning_(cookware)
Posters comment: Even
if you use left-over Teflon type cookware(like passed down to you) with many
scratches in it from use, just oiling it (if you can) and wiping it clean is a
good idea to try out. And of course periodically boil it out to kill the
germs. In the meantime, heating this
kind of cookware will also kill the germs.
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