Before the advent of infrared moisture analyzers, gummy drying was an art as much as a science. Operators relied on a combination of tactile observation, visual cues, and hands-on experience that constituted the "tacit knowledge" of the craft, which is now largely lost to automation. This know-how was never written down but was passed from veteran to apprentice on the production floor.
Key Tacit Knowledge of Pre-IR Moisture Control
1. The “Stick Test” and Tactile Feedback
The most common method was the stick test. An operator would gently press a gloved finger into the surface of a gummy. The response told them everything:
- Too wet: The gummy would feel tacky or leave a residue on the glove. The surface would be soft and easily deformed, often sticking to the tray.
- Just right: The gummy would spring back slightly when pressed, with a smooth, slightly firm surface that did not adhere to the finger. This was the "sweet spot" of final moisture content.
- Too dry: The gummy would feel hard, brittle, or rubbery, and the surface might look slightly cracked or chalky.
This test required a practiced, consistent touch. Different gummy recipes (pectin-based vs. gelatin-based) felt different at the same moisture level, so operators developed an intuitive feel for their specific product.
2. Visual Surface Appraisal
Operators became expert at reading the surface of a gummy for clues:
- Shine: A high, uniform gloss indicated adequate moisture content. A dull, matte surface was a sign of over-drying or "case hardening."
- Firmness and Skin: The formation of a thin, dry "skin" on the surface while the interior remained moist was a critical sign of correct drying progress. Operators learned to recognize the precise texture and opacity of that skin.
- Edge checking: Tiny cracks at the corners or edges of gummies were a late-stage warning of over-drying.
3. Weight and Feel of a Whole Tray
While not precise, experienced operators could tell moisture content by the weight of a full drying tray in their hands. They developed a kinesthetic memory for how a tray of finished gummies (at the correct final moisture) should feel versus a tray of wetter gummies. They also learned the subtle sound of a properly dried gummy when gently tapped against the tray-a solid, non-sticky thud versus a dull, sticky slap.
4. The “Break Test” and Internal Moisture Gradients
A more invasive check was the break test. An operator would snap a gummy in half to examine the internal structure:
- A clean break with a smooth, non-sticky interior indicated uniform drying.
- A gummy that bent instead of breaking or showed a tacky interior core was still too wet and needed more time in the drying rooms.
- An overly dry gummy often cracked before breaking, revealing a dry, porous center.
What Is Now Lost?
While automation with infrared analyzers brings consistency and speed, the tacit knowledge of sensory-based moisture assessment is difficult to replicate. Operators who honed these skills could:
- Predict drying times by feeling the humidity in the room and the texture of the first batch of the day.
- Adjust recipes on the fly by noticing subtle shifts in a gummy's texture, alerting them to inconsistent raw materials (e.g., gelatin bloom or citric acid variability).
- Detect problems early-a slight tackiness on a tray might signal a cooling unit malfunction before any alarm went off.
Today, many production managers and experienced operators at KorNutra have retired, taking this sensory expertise with them. Newer staff are trained to trust the analyzer’s numbers rather than their fingers. While this reduces inconsistency, it also means a finer sensitivity to process variation is lost-the ability to feel when a batch is "just right" even if the machine says it's 0.2% off target. At KorNutra, we still value the intersection of this historic craft and modern precision, but we acknowledge that the human touch in moisture analysis is now a fading art. The best operators today combine the data from their analyzers with a trained eye and a gentle press of the thumb.