On food and cooking the science and lore of the kitchen ( PDFDrive ) 1495

arrangementdeterminedbytheirgeometry.In
solidwater,however,themolecularpackingis
dictatedbytherequirementforeven
distributionofhydrogenbonds.Theresultisa
solidwithmorespacebetweenmoleculesthan
theliquidphasehas,byafactorofaboutoneeleventh.It’sbecausewaterexpandswhenit
freezesthatwaterpipesburstwhentheheat
failsinwinter;thatbottlesofbeerputinthe
freezerforaquickchillandthenforgotten
willpopopen;thatcontainersofleftoversoup
orsaucewillshatterinthefreezerifthey’re
toofullfortheliquidtoexpandfreely.And
it’swhyrawplantandanimaltissuesare
damagedwhenthey’refrozenandleakliquid
whenthawed.Duringfreezing,theexpanding
icecrystalsrupturecellmembranesandwalls,
whichthenloseinternalfluidswhenthe
crystalsmelt.
HardWater:DissolvedMinerals
Water is so good at dissolving other


substances that apart from distilled water,
it’s seldom found in anything like pure
form. Tap water is quite variable in
composition, depending on its ultimate
source(well,lake,river)anditsmunicipal
treatment (chlorination, fluoridation, and
soon).Twocommonmineralsintapwater
are carbonate (CO3) and sulfate (SO4)
salts of calcium and magnesium. Calcium

and magnesium ions are troublesome
because they react with soaps to form
insoluble scums, and because they leave
crusty precipitates on showerheads and
teapots.Suchso-calledhardwatercanalso
affect the color and texture of vegetables,
and the consistency of bread dough (pp.
282, 535). Hard water can be softened
eithercity-wideorinthehome,usuallyby
one of two methods: precipitating the
calciumandmagnesiumbyaddinglime,or
using an ion-exchange mechanism to
replace the calcium and magnesium with