On food and cooking the science and lore of the kitchen ( PDFDrive ) 1186

beaten into 1 egg yolk plus water gives a
sparse emulsion of coarse, unevenly sized oil
droplets(left).Eighttablespoons/120mlofoil
give a tightly packed, semisolid emulsion of
small droplets (right).The yolk emulsifiers
and stabilizing proteins must be effective
enough to withstand considerable physical
pressure in order to prevent the oil droplets
fromcoalescingintoaseparatelayer.
MakingBillionsofDropletsfromOne
TablespoonIt’sonaccountofsurface
tension,then,thatthecookmustpourenergy
intotheliquidtobedispersed.Tomakea
sauce,itsnaturalmonolithicarrangement
mustbeshattered.Andseriouslyshattered:
whenyoubeatasingletablespoon/15mlof
oilintoamayonnaise,youbreakitupinto
about30billionseparatedroplets!Serious
whiskingbyhandorinakitchenmixer
providesenoughshearingforcetomake
dropletsassmallas3thousandthsofa
millimeteracross.Ablendercangetthem


somewhatsmaller,andapowerfulindustrial
homogenizercanreducethemtolessthanone
thousandthofamillimeter.Thesizeofthe
dropletsmatters,becausesmallerdropletsare
lesslikelytocoalescewitheachotherand
breakthesauceintotwoseparatephases
again.Theyalsoproduceathicker,finer

consistency,andseemmoreflavorfulbecause
theyhavealargersurfaceareafromwhich
aromamoleculescanescapeandreachour
nose.
Twofactorsmakeiteasierforthecookto
generatesmalldroplets.Oneisthethickness
ofthecontinuousphase,whichdragsharder
onthedropletsandtransfersmoreshearing
forcetothemfromthewhisk.Shakealittle
oilinabottleofwater,andtheoildropletsare
coarseandquicklycoalesce;shakealittle
waterinthemoreviscousoil,andthewater
getsbrokenintoapersistentcloudofsmall
droplets.It’shelpful,then,tostartwithas
viscousapartofthecontinuousphaseas