How are candied fruits made with progressively stronger sugar syrups?

Candied fruits are produced through a process of slow impregnation, where the fruit is treated with syrups of progressively increasing sugar concentrations.1

This gradual increase in sugar concentration is essential to ensure that the sugar content within the fruit tissue becomes high enough to inhibit the growth of spoilage microorganisms without causing the fruit to lose its structural integrity. By carefully controlling the concentration levels, processors prevent the fruit from softening into jam or becoming tough and leathery.1

Once the fruit has been sufficiently impregnated with sugar, it is washed and dried. The final product may be marketed as candied fruit or further processed into glacéed fruit by dipping it into syrup to create a thin, sugar-based glaze, followed by a final drying stage.1