The production of hard candies, with or without centrefills or coated gums (sugar-free / sugar gum) is an intricate process. The material is in a plastic state during the manufacturing process. It must flow and be shaped by a stamping machine. The natural foe which inhibits the free flow is the ever-present moisture in the air. Sugar, being hygroscopic by nature, becomes sticky when exposed to highly humid conditions. The moisture also interferes with the operation of the processing machine.

One of confectionery manufacturers' worst fears is high humidity in production facilities. Candy quality deteriorates when humid conditions exist in three primary areas: coating, cooling, packaging and storage areas.


The only solution to the problem lies in surrounding the processing and manufacturing area with dry air.

One of the most widely used coating techniques is pan coating. The term pan comes from the coating apparatus used to coat soft-centre candy with a harder candy shell. This would include candy with soft jelly centres, chocolate centres, centres with combinations of chocolate and nuts, gum pallets - sugar- free / sugar-coated and many others. The coating pans are used to apply the outer coating into the raw centres as they tumble in a large drum. Spray nozzles mounted inside the pan coater drums evenly distribute the liquid to form the outer coating shell. Heat is applied to the pans so that the liquid in the coatings evaporates and the hard shell is formed. If the heated air blowing through the pans is too moist, the drying times are significantly longer and, therefore, the throughput is greatly diminished. The drying of the coatings applied in pans becomes the critical factor in maximising the throughput in this entire production cycle.

Temperatures of air flowing through cooling tunnels can be lower if the dehumidification units have decrease the moisture content. Dry air in the cooling tunnels prevents condensation that could drip on the candy, and lower temperatures save energy costs.

Fast, uniform cooling is the only way to achieve even coating thickness on the exterior of candy with soft-coatings, such as chocolate covered bars. If the cooling air was not uniformly dehumidified, the result could be thin coatings near the top of the candy and "skirts" (thick coatings) at the bottom.

Dehumidified air translates into faster packaging processes and longer shelf lives in storage areas. Lower humidity also means less risk of mould and fungus accumulation in the processing areas.
Temperature and humidity requirement chart for some common confectionery items

The humidity threat
The solution to the problem lies in maintaining required stringent conditions of temperature and humidity and in surrounding the processing, packaging and storage areas with dry air. Dehumidifiers that lower the moisture content of the surrounding air maintaining RH as low as 1% at a constant level regardless of the ambient conditions during the production, storage and packing to help improve the quality and retain the freshness of the chocolates and other confectionery longer.