Stickiness in hard candy (2024)

With a modest increase in moisture, glass transition temperature (Tg )drops dramatically. If used a high DE glucose syrup, you'll end up with too many low molecular weight sugars, resulting in a sticky candy with a reduced glass transition temperature (Tg). 42DE is a commonly used glucose syrup for hard candy. Higher levels of glucose syrup in the recipe (50–60% dry basis) avoid sucrose crystallization but result in stickiness and less sweet candies.

The addition of more liquid flavor lowers the glass transition temperature (Tg), making candies more susceptible to changes during storage, resulting in graining, taste loss, and cold flow.

If there is more acid in hard candy, it will invert and become sticky. Check the acidity of the filling as well. Acids promote sucrose inversion, especially at high temperatures, and are added after cooking, along with flavorings. The sucrose inversion at high temperature and low pH produces glucose and fructose, resulting in unstable candies with lower glass transition temperature and more stickiness, , and graining (crystallization) and shorter shelf life. (Acids should be added as a powder.)

To counteract potential inversion issues, buffer salts like sodium citrate can be employed.Bicarbonate and organic acids may be present in powdered centers to generate a fizzy effect when eaten. However, two components must be maintained separate, which is commonly accomplished by covering one of the products with a fat layer. If penetrated inside hard candy it might cause sucrose inversion and softening.

A hard candy with a higher percentage of invert sugar has a lower quality and has a shorter shelf life. Because of the greaterhygroscopicity and low glass transition temperature. Stickiness is common in candy with a high fructose content, weatherthrough direct addition or sucrose inversion.

For hard candy, a common target range of total DE is 16-18%. Concentrated hard candy has an equilibrium related humidity of 20-30%, Relative humidity more than 30%, hard candy will absorb moisture.

Because of the variation in moisture content between the center and the surface, water molecules in the surrounding can only permeate into the sugar glass. Water migration to the bulk of the sugar glass is very slower; sugar candy exposed to damp air can take up to a month to reach equilibrium in terms of moisture content across the candy. Because moisture migration to the interior is slower than water molecule absorption to the surface.

Sugar has a sticking point that is around 10 degrees Celsius higher than its glass transition temperature Tg value.

Other reasons are

Stickiness will result from a low cooking temperature.

Packing materials that aren't up to snuff.

In the processing area, there is more humidity.