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Drying is one of the standard processes in the food industry. In contrast to conventional drying processes, the infrared rotating drum dryers developed by Kreyenborg operate with electromagnetic waves. The light energy thus generated penetrates directly into the inside of the food to be dried and is transformed into heat. The moisture to be evaporated is drawn out directly without cornification of the material to be dried.

A direct comparison between the two drying processes reveals the advantages of short-wave infrared technology on several different levels. One decisive aspect which influences the quality of the food products is that the drying process is controlled directly by the product temperature rather than via the drying air. Temperature regulation with an accuracy down to a single degree, together with minimal dwell times inside the dryer, promote extremely gentle treatment of the product. The energy balance of infrared dryers is also very positive because no preheating of the appliance is necessary. Production can start immediately. Consequently, this system achieves an excellent degree of efficiency. In terms of structural features, the Kreyenborg appliance stands out by its simple, compact design, which is hygienic and easy to clean in compliance with the standards and directives governing the food industry. All parts coming into contact with the product are made of stainless steel.

The infrared dryer operates in a particularly cost-efficient way in final drying down from about 30 % residual moisture in the material to be dried, since convection dryers no longer operate effectively below this threshold value. If the conventional drying process is terminated at that point and the product transferred to a Kreyenborg infrared dryer for final drying, a significant increase in drying capacity and improvement of the end product quality can be achieved, with a simultaneous reduction in drying costs.
In several test series at the pilot plant of the project partner, ps: perfect solutions in Meiningen, it has also been proved that substantially better results in terms of flavour, colour and texture can be achieved by using infrared light energy in roasting the dried materials. This is largely due to the fact that the roasting process is substantially shortened under infrared light and takes place at a significantly lower product temperature as well.