Properties of Hard Candy

• Crystalline sugar based confection
• Low water content and a hard, glassy texture
• Not the same as rock candy
  • Rock candy has molecules tightly bonded in a lattice
  • Hard candy is amorphous/glassy
    • High viscosity prevents flow
    • Molecules packed closely together but randomly

Ingredients

• Sucrose, corn syrup, acids, colors and flavors
• Other ingredients: Fats, milk ingredients, fruit juice etc.

Making Hard Candy

• Boil sugar syrup to 295-305F (148-152C) and cool rapidly
  • Add a id and flavor after cooking to prevent thermal degradation
• The relationship between temperature and water content is governed by boiling point elevation
  • 295-305F corresponds to a water content of ~ 3-4%

Cooling and Forming

• Once the candy mass has been cooked it can be formed into desired shape
• Cool to intermediate temperature where mass has a plastic state
• Alternative method: deposit hot liquid into mold

Stability

• Keep below glass transition temperature to maintain shape

Sugar Free Hard Candy

• To make a hard candy with a polyol must use an ingredient with a high Tg to prevent cold flow
  • Isomalt and maltitol meet this requirement
• Follow some process to make
  • Possibly cook to a little higher temperature to reduce water content below 1% to raise Tg

End of Shelf life

• Depends on type of sweeteners
  • Too much corn syrup leads to stickiness
  • Too much sucrose leads to graining