On food and cooking the science and lore of the kitchen ( PDFDrive ) 1209
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kindsofwater-basedliquidsandsemisolids
thatcontaindissolvedorsuspendedor
structure-stabilizingmoleculesofsomekind.
TheCatalanchefFerranAdriàpioneeredthis
development,withfoamsof—amongother
ingredients—cod,shellfish,foiegras,
asparagus,potatoes,raspberries,andcheese.
Cookingbrothsandtheirreductions,proteinandstarch-thickenedsauces,juices,purees,
andemulsifiedsaucescanallbelightenedby
incorporatingbubblesintothem.Andit’sa
quicklast-minutepreparation:justagitate
someoftheliquiduntilitfroths,thenscoop
offthebubble-richportion,addittothefood,
andserve.
MakingandStabilizingFoams
Thereareseveraldifferentwaysofgetting
bubblesintoaliquidandstabilizingthem.
Whippingwithawhiskorhand-heldblender
introducesairbyagitatingtheliquidsurface;
thefoamingwandsonespressomachines
shootsteam,amixtureofwatervaporandair;
andfoamingdevicesforwhippedcreamand
seltzerwatermixastreamofpressurized
carbondioxideornitrousoxidewiththe
liquid.Anydissolvedorsuspendedmolecules
intheliquidcollectattheinterfaceoftheair
andliquidandgivethebubblewallsomesolid
reinforcement.
However,thereinforcementwillbe
momentaryandthebubblesshort-livedunless
themoleculescanformastablelayeratthe
interface.Thisisexactlywhatemulsifierslike
lecithinandproteinsdo,andforthesame
reasonthattheystabilizeoildropletsin
emulsions:theyhaveawater-solubleportion
thatrestsinthebubblewall,andawaterinsolubleportionthatrestsintheair.Because
thebubblesinatypicalfoamarebetween0.1
and1millimeteracross,muchlargerthan
mostemulsiondroplets,theyrequirevery
littleemulsifiertocovertheirsurfacearea,
