When product comes off warm at the end of a round and the packs have melted, the warehouse usually suggests one more pack. More often the shortfall is not the number of packs but cold that was spent elsewhere before the van even left. So first the product and the record are protected, then six points are checked in order.
Segregate the affected product; keep lot, product and air readings, logger identity and the last good record in one file. If the sensor sat only near a pack, its result does not represent the load. If the start or end reading is missing, do not estimate the duration; record an unknown interval. For food, what happens to the affected product is a separate decision; the FAO HACCP guidance treats it apart from restoring process control.
- Was the pack fully frozen. GEBHARDT eutectic plates must be completely solid before use, frozen at least 5 °C below their melting point, with an air gap between plates. Freezing takes 8 to 24 hours depending on the cooling method; a plate taken out early leaves with liquid inside and works for less time.
- Was the container pre-chilled. The body of a container that stood warm eats part of the pack's energy in the first hour; keeping the container in the cold area before loading costs less than an extra pack.
- Was the product loaded cold. A pack is there to keep product cold, not to cool it; in a container loaded with warm goods it spends its energy pulling them down.
- How often did the lid open. Cold air escapes at every opening and the loss builds up with the number of stops. Reordering the route or using smaller containers can give the same result without adding packs.
- Does the melting point suit the product. GEBHARDT plates come with melting points of -3, -14, -18 and -21 °C. A point far below what the product needs spends energy in the wrong range; one set too high never brings the product down to target.
- Is the container really insulated. A cardboard box or thin-walled crate gives the pack's cold away; the same pack works several times longer in an insulated container.
Do not change all six in the same round. If one factor changes per round you learn which one worked; change everything at once and the result may improve without teaching you anything. In a comparison, keep product, box, pack preparation and sensor positions the same and record air and product readings together.
If it still falls short after these six, adding packs is the right decision, and the extra pack is then a measurement result rather than a guess. When adding, check space, mass and closure; for freeze-sensitive goods also check that the lower limit is not crossed. Send us the route and container details and we select the plates together with you.
