On food and cooking the science and lore of the kitchen ( PDFDrive ) 580
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and pectins. Candying can be a tedious
process because it takes time for sugar to
diffuse from the syrup evenly into the fruit.
Typically the fruit is gently cooked to soften
it and make its tissues more permeable, then
soaked for several days at room temperature
inasyrupthatstartsoutat15–20%sugar,and
is made more concentrated each day until it
reaches70–74%.
Canning
Canningwasacauseforwonderwhenitwas
inventedbyNicolasAppertaround1810:
contemporariessaidthatitpreservedfruits
andvegetablesalmostasiffresh!True,it
preservesthemwithoutthedesiccatedtexture
ofdrying,thesaltandsournessof
fermentation,orthesweetnessofsugar
preserves;butthere’snomistakingthat
cannedfoodshavebeencooked.Canningis
essentiallytheheatingoffoodthathasbeen
isolatedinhermeticallysealedcontainers.The
heatdeactivatesplantenzymesanddestroys
harmfulmicrobes,andthetightsealprevents
recontaminationbymicrobesinthe
environment.Thefoodcanthenbestoredat
roomtemperaturewithoutspoiling.
Thearchvillainofthecanningprocessis
thebacteriumClostridiumbotulinum,which
thrivesinlow-acid,airlessconditions—
oxygenistoxictoit—andproducesadeadly
nervetoxin.Thebotulismtoxiniseasily
destroyedbyboiling,butthedormant
bacterialsporesareveryhardyandcan
surviveprolongedboiling.Unlesstheyare
killedbytheextremeconditionofhigherthan-boilingtemperatures(whichrequirea
pressurecooker),thesporeswillproliferate
intoactivebacteriawhenthecancoolsdown,
andthetoxinwillaccumulate.One
precautionarymeasureistoboilanycanned
produceafteropeningtodestroyanytoxin
thatmaybethere.Butallsuspectcans,
