First mark where water appears: on the product, inner wall or around the lid? Measure air temperature and relative humidity at the same time and calculate dew point; use a contact probe to record the temperature of the wet surface.
Condensation is possible when a surface is at or below dew point. A warm load, a cold product moved into warm humid air, lid opening or a leak can create wetness by different routes. One observation does not prove the cause; also record load temperature, packaging and lid events.
Repeat readings at the same location and route stage. Depending on the findings, trial preconditioning, shorter openings, water collection or packaging protection; assess the change using before-and-after temperature and wetness records.
