Three things set the freezing time: how far below the pack's melting point the freezer runs, how thick the pack is, and whether cold air can circulate around it. GEBHARDT plates are 34 mm thick, and GEBHARDT recommends a separate freezing temperature for each melting point.
| Melting point | Recommended freezer temperature | Recommended time |
|---|---|---|
| -3 °C | -8 °C | 24 hours |
| -14 °C | -19 °C | 24 hours |
| -18 °C | -23 °C | 24 hours |
| -21 °C | -26 °C | 24 hours |
GEBHARDT gives the time as 8 to 24 hours depending on the cooling technology; a blast freezing cell sits near the lower end of that range, a freezer whose door opens often near the upper end. If the freezer runs close to the melting point, say a -18 °C plate in a -20 °C room, only two degrees drive the heat out; the time grows markedly and the filling may never solidify completely.
When plates are stacked on top of each other, the ones in the middle freeze much later than the outer ones. That is why GEBHARDT always requires an air gap between plates and builds its freezer racks to keep that gap. A warm load entering the freezer at the same time also lengthens the time.
- Place the plates on the rack at least 24 hours before dispatch, with gaps between them.
- Read the freezer temperature at rack level; if it does not reach 5 °C below the melting point, freezing takes longer.
- Before loading, check that the filling is solid all the way through; GEBHARDT requires the filling to be completely frozen before use.
- When a new pack type or rack layout arrives, time the first batch again and write it into the shift instruction.
If freezing takes 24 hours, a line dispatching every day needs at least two sets of plates: one on the road while the other waits in the freezer. When sizing the freezer, count the rack area taken by plates set out with air gaps, not only the volume.
