Cooling Tunnel Common Selection Mistakes to Avoid

Mistake 1: Under-Sizing the Tunnel

A tunnel too short for the belt speed—product exits soft and you slow the line to compensate, losing rated output.

Solution: Size for your real belt speed, with a safety margin for future scale-up.

Mistake 2: One Cold Zone Instead of a Curve

Running the entire tunnel at one temperature creates cracks and dull tops from thermal shock.

Solution: Specify a minimum of three independently controlled temperature zones.

Mistake 3: Ignoring Dew Point

Cooling below the dew point causes sugar bloom on good chocolate—rejected as defective.

Solution: Hold the cooling curve above the dew point, and give the refrigeration margin for the worst ambient conditions.

Mistake 4: Under-Sized Refrigeration for Hot Climates

The tunnel cannot hold its zones in summer, exactly at peak production.

Solution: Size refrigeration for the worst ambient conditions, not average.

Mistake 5: Forgetting Cleanability

Complex tunnel designs can create hard-to-reach areas where product residue accumulates.

Solution: Check if the tunnel can be cleaned easily—inlet and exit edges should have as small a diameter as possible (not more than 20 mm).