On food and cooking the science and lore of the kitchen ( PDFDrive ) 1023

andthehotair.Ifsteamispresent,itprovides
aninitialblastofheatbycondensingontothe
colddoughsurface.Heatthenmovesfromthe
surfacethroughthedoughbytwomeans:slow
conduction through the viscous gluten-starch
matrix, and much more rapid steam
movement through the network of gas
bubbles. The better leavened the dough, the
faster steam can move through it, and so the
fastertheloafcooks.
Asthedoughheatsup,itbecomesmore
fluid,itsgascellsexpand,andthedoughrises.
Themaincauseofthisovenspringisthe
vaporizationofalcoholandwaterintogases
thatfillthegascells,andthatexpandthe
doughbyasmuchashalfitsinitialvolume.
Ovenspringisusuallyoverafter6–8minutes
ofbaking.
Mid-Baking: From Foam to Sponge Oven
springstopswhenthecrustbecomesfirmand
stiffenoughtoresistit,andwhentheinterior


of the loaf reaches 155–180ºF/68–80ºC, the
temperature range in which the gluten
proteins form strong cross-links with each
other and the starch granules absorb water,
swell,gelate,andamylosemoleculesleakout
ofthegranules.Nowthewallsofthegascells
can no longer stretch to accommodate the
rising pressure inside, so the pressure builds

andeventuallyrupturesthewalls,turningthe
structureoftheloaffromaclosednetworkof
separate gas cells into an open network of
communicatingpores:fromanaggregationof
little balloons into a sponge through which
gases can easily pass. (If the dough were not
transformedintoasponge,thencoolingwould
causeeachisolatedgascelltoshrink,andthe
loafwouldcollapse.)