On Food and Cooking

allow   the syrup   to  cool    before  initiating

crystallization

avoid   agitating   the syrup   while   it  cools

when    the syrup   is  cool,   agitate

continuously    and vigorously  for as  long

as  the syrup   is  workable

Preventing Crystal Formation: Making
Sugar into a Glass Candy makers produce an
entirely different structure and texture when
they cool a syrup so rapidly that the sugar
molecules stop moving before they have a
chance to form any crystals at all. This is how
transparent hard candies are made. If the
water content of the cooked syrup is just 1 or
2%, then it’s essentially molten sugar with a
trace of water dispersed in it. The syrup is
very viscous, and if it cools quickly, the
sucrose molecules never have a chance to
settle into orderly crystals. Instead, they just
set in place in a disorganized mass. Such an
amorphous, noncrystalline material is called a