On food and cooking the science and lore of the kitchen ( PDFDrive ) 205

sulfur-sulfur(S-S)connectionwitheach
other.Theadditionofanacidbooststhe
numberoffree-floatinghydrogen(H)ionsin
theeggwhite,whichmakesitmuchharderfor
theS-HgroupstoshedtheirownH,andso
slowsthesulfurbondingdowntoacrawl.A
gooddoseis1/8teaspoon/0.5gcreamoftartar
or½teaspoon/2mllemonjuicepereggwhite,
addedatthebeginningofthebeating.
TheEnemiesofEggFoams

Therearethreeenemiestothesuccessful
mountingofafoamwhichthecookshouldbe
carefultoexcludefromthebowl:eggyolk,oil
orfat,anddetergent.Allarechemical
relatives,andinterferewithfoaminginthe
sameways:bycompetingwiththeproteins
foraplaceattheair-waterinterfacewithout
offeringanystructuralreinforcement;andby
interferingwiththebondingoftheprotein
molecules.Tracesofthesetroublemakers


won’tabsolutelypreventyoufrommakinga
foam,butthey’llmakeyouworkharderand
longer,andthefoamwon’tbeaslightor
stable.Ofcourseyolkandfatcansafelybe
mixedwithafinishedfoam,ashappensin
manyrecipesforsoufflésandegg-leavened
batters.

Copper bowls and eggs in the 18th century.
Thisisadetailof “Pâtissier,”or“ThePastrycook,”from the Encyclopédie, an engraving
first published in 1771. The boy at right
wields what the accompanying key calls “a
copper bowl for beating egg whites and
mixing them with the dough from which
biscuitsaremade.”
TheEffects
ofOtherIngredients