A business that sets its chamber to -22 °C tends to assume it can freeze the -14 plate comfortably. GEBHARDT requires the fill to be fully frozen and solid before use and sets the freezing temperature at least 5 °C below the melting point. The catalogue values are below; the recommended time is 24 hours for all of them.
| Melting point | Recommended freezing temperature |
|---|---|
| -3 °C | -8 °C |
| -14 °C | -19 °C |
| -18 °C | -23 °C |
| -21 °C | -26 °C |
-22 °C is 3 degrees colder than the minimum for the -14 plate. Because the freezing rate grows with the difference between plate and air, the last core freezes late when that difference is small, and small swings in the chamber stretch the time. GEBHARDT states that freezing time varies between 8 and 24 hours with the cooling technology.
Leave an air gap between plates so cold air can circulate; GEBHARDT recommends freezing racks for this. In a packed chamber the real temperature differs between shelves even when the setting is right. If you feel liquid when you shake a plate, it is not frozen yet; measure the freezing time in your own chamber on the first cycle and build the shift plan on it.
