Forming Candy Crystals
Date: April 2009
How do candy crystals form?
To get sugar crystals, you have to start by dissolving sugar in water,
and then you have to make the sugar want to come back out of solution
as a crystal. There are a couple ways to coax the sugar back out of
solution -- the easiest way is to heat up water and dissolve as much
sugar as you can, and then let the solution cool down. More sugar can
'fit' into the water when it is hot than when it is cold, so the extra
sugar will form crystals once the water cools. If the water cools
slowly, very large crystals can form. Sugar crystals made this way are
known as 'rock candy'. The second way, which is more common in
traditional candy making, is to dissolve sugar and water (the amounts
do not matter that much as long as the sugar dissolves) and then start
cooking it in a pan. The longer you cook, the harder the sugar
crystals will be when they cool (longer cooking means more water
evaporates, and less water means harder crystals). You can use a candy
thermometer to tell you how hard your candy will be once it cools --
from chewy all the way to rock hard.
Hope this helps!
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Update: June 2012