Rock Candy

We use to make Rock candy when I was young
this is the recipe from my Grandmother.

Ingredients:
4 (12-oz.) glass canning jars
4 (7-inch) pieces clean kitchen string
4 wooden skewers or pencils
4 1/2 cups sugar
2 cups water
10 drops red food coloring*
1/8 teaspoon cinnamon oil*
2 teaspoons vanilla extract

Directions:
Arrange jars in bottom of a large Dutch oven,
and fill with enough water to cover jars by 1 inch.
Bring to a boil over medium-high heat
boil 2 minutes (this is to sterilize).
Carefully remove jars with kitchen tongs
to a wire rack; cool completely, and dry.
Tie strings around centers of wooden skewers.
Place one string in each jar,
resting skewer across rim of jar,
and making sure strings
do not touch bottoms of jars. Set aside.
Bring sugar and 2 cups water to a boil
in a large saucepan over medium-high heat,
stirring occasionally, boil,stirring occasionally, 5 minutes.
Remove from heat. Stir in food coloring,
cinnamon oil, and vanilla. Let stand 5 minutes.
Pour about 1 cup syrup mixture carefully
around skewer into each jar.
Loosely cover with aluminum foil
(including skewer),pierce aluminum foil
several times with a skewer or knife.
Let stand 10 to 14 days
or until crystals form on strings.
(Occasionally break up hard sugar layer
on surface using a wooden skewer.)
Remove strings from jars,
and suspend strings between jars
until crystals are dry (about 1 hour).
Remove strings from skewers.