On food and cooking the science and lore of the kitchen ( PDFDrive ) 1148
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thegelatinchains.Thebestwaytoassessgel
strengthistocoolaspoonfuloftheliquidina
bowlrestinginicewater,seeiftheliquidsets,
and how firm the gel is. A liquid lacking in
firmnesscanbereducedfurthertoconcentrate
the gelatin, or it can be supplemented with a
smallamountofpuregelatin.
Howgelatinturnsaliquidintoasolid.When
thegelatinsolutionishot(left),thewaterand
protein molecules are in constant, forceful
movement. As the solution cools and the
molecules move more gently, the proteins
naturally begin to form little regions of
collagen-like helical association (right).
These “junctions” gradually form a
continuous meshwork of gelatin molecules
that traps the liquid in its interstices,
preventing any noticeable flow. The solution
hasbecomeasolidgel.
AdditionalIngredientsOthercommon
ingredientshavevariouseffectsongel
strengthwhenincludedinajelly.
Saltlowersgelstrengthbyinterfering
withgelatinbonding.
Sugars(exceptforfructose)increasegel
strengthbyattractingwatermolecules
awayfromthegelatinmolecules.
Milkincreasesgelstrength.
Alcoholincreasesgelstrengthuntilit
becomes30to50%ofthegel,whenit
willcausethegelatintoprecipitateinto
solidparticles.
Acids—vinegar,fruitjuices,wine—
withapHbelow4produceaweakerjelly
byincreasingrepulsiveelectricalcharges
onthegelatinmolecules.
The gel-weakening effects of salt and acids
can be compensated for by increasing the
