On food and cooking the science and lore of the kitchen ( PDFDrive ) 1489

steel pans improve their easily corroded
surfacebybuildingupanartificialprotective
layer. They “season” them by coating them
withcookingoilandheatingthemforseveral
hours. The oil penetrates into the pores and
fissures of the metal, sealing it from the
attack of air and water.And the combination
of heat, metal, and air oxidizes the fatty acid
chains and encourages them to bond to each
other (“polymerize”) to form a dense, hard,
dry layer (just as linseed and other “drying
oils” doon wood and on paintings). Highly
unsaturated oils — soy oil, corn oil — are
especially prone to oxidation and
polymerizing. To avoid removing the
protective oil layer, cooks carefully clean
seasonedcastironpanswithmildsoapsanda
dissolving abrasive like salt, rather then with
detergentsandscouringpads.
StainlessSteel


Theimportantexceptiontotherulethat
metalsformprotectivesurfacecoatingsis
iron,whichrustsinthepresenceofairand
moisture.Theorangecomplexofferricoxide
andwater(Fe2O3• 2O)isaloosepowder
ratherthanacontinuousfilm,andsodoesnot
protectthemetalsurfacefromfurthercontact
withtheair.Unlessit’sprotectedbysome
othermeans,ironmetalwillcorrode

continuously(thisiswhypureironisnot
foundinnature).Effortstomakethischeap
andabundantelementmoreresistantto
rustingresultedinthe19thcenturyinthe
developmentofstainlesssteel,aniron-carbon
alloythat—incookware—isformulated
withabout18%chromiumand8–10%nickel.
Chromeissynonymouswithbrightand
permanentshininessbecausechromiumis
extremelypronetooxidationandnaturally
formsathickprotectiveoxidecoat.Inthe
stainlesssteelmixture,oxygenreacts
preferentiallywiththechromiumatomsatthe