At KorNutra, we see moisture control as one of the hardest parts of gummy production, especially when a batch cracks during cooling. Hard candy and candy-cane producers solve this center-cracking problem by cooling boiled sugar slowly, holding the mass at a working temperature so the surface doesn't set hard while the center contracts, and keeping room humidity steady so condensation never forms. A gummy maker faces the same gradient: the outer layer firms faster than the interior, skinning the surface, splitting it, or trapping moisture that later turns it tacky.
To minimize the gradient, gummy manufacturers can act in four places:
- Controlled cooling rates: Replace rapid chilling with a gradual, staged cool so the interior moisture equilibrates with the outer layer and reduces differential shrinkage.
- Humidity management: Hold stable, moderate humidity in the cooling and drying rooms. High humidity causes surface condensation; low humidity pulls moisture off the surface too fast. Both steepen the gradient.
- Ingredient formulation: Humectants such as glycerin or sorbitol hold moisture evenly in the gum base and slow its migration during cooling and drying.
- Post-cooling conditioning: Rest gummies in a climate-controlled room after cooling and before packaging so the gradient stabilizes. Setting and drying are different; a piece firm enough to demold can still need conditioning time.
Water activity as the control metric
Moisture content alone won't tell a gummy maker when the gradient has settled; two batches with the same water content can behave differently. The measurable target is water activity (aw), the water free to migrate rather than the total present. Water activity beats a dry-feeling surface as the pass/fail test. No single water activity target fits every gummy supplement; it depends on the formula, coating, package, and shelf-life target. Conditioning to a defined water activity range instead of a fixed drying time stops the delayed tack that appears when a gummy is packaged too early.
The comparison has limits. Candy-cane production is food manufacturing under the food CGMPs in 21 CFR Part 117; a gummy sold as a supplement falls under 21 CFR Part 111. The physics transfers; the documentation and process controls differ. At KorNutra, we emphasize that no medical or health claims should be made about specific supplements or ingredients; this advice is manufacturing practice, not ingredient effects. A controlled cool is how hard candy avoids cracks; gummies held to a measured water activity target get the same result out of the drying room.