On food and cooking the science and lore of the kitchen ( PDFDrive ) 1468

—butbythevibrationofindividual
moleculesoraportionofthelattice,whichis
transferredtoneighboringareas.Thistransfer
ofvibrationisamuchslowerandless
efficientprocessthanelectronmovement,and
nonmetalsarethereforeusuallyreferredtoas
thermalorelectricalinsulators,ratherthan
conductors.Liquidsandgases,becausetheir
moleculesarerelativelyfarapart,arevery
poorconductors.
Theconductivityofamaterialdetermines
itsbehavioronthestove.Thebetterthe
conductor,thefasterapanheatsupandcools
off,andthemoreevenlyheatisdistributed
acrossthepanbottom.Unevenheatingcreates
hotspotsthatcanburnfoods:duringfrying,
forexample,ortheboilingdownofapureeor
sauce.
ConductionWithinaFoodHeatalsotravels
fromtheoutsidetothecenterofasolidpiece
offood—apieceofmeatorfishorvegetable


— by means of conduction. Because the
cellular structure of foods impedes the
movementofheatenergy,foodsbehavemore
like insulators than like metals, and heat up
relatively slowly. One of the keys to good
cookingisknowinghowtoheatafoodtothe
desired doneness at its center without
overheating its outer regions. This is not a

simple task, because different kinds of foods
heat through at different rates. One of the
most important variables is the thickness of
the food. Though common sense might
suggest that a piece of meat one inch thick
wouldtaketwiceaslongtocookthroughasa
half-inch piece, it turns out that it takes
somewhere between twice and four times
longer, depending on the overall shape: less
foracompactchoporchunk,moreforabroad
steak or fillet. There’s no absolutely reliable
way to predict how long it will take heat to
move from the food surface to its center, so
the best rule is to check the doneness