Monitoring a Freeze Drying Batch

Monitoring a batch means watching what the machine is telling you during the run. The most useful data are vacuum pressure and shelf temperature. Vacuum pressure shows how well vapor is being removed. During heavy sublimation, pressure may be higher, then trend lower as moisture decreases. Big spikes or unstable readings can point to leaks or pump problems. Shelf temperature shows how much heat the machine is applying. During primary drying, temperatures stay lower to protect frozen structure. During secondary drying, temperature rises to remove bound moisture. Avoid opening the chamber during a run because it breaks vacuum and adds time. Instead, use the machine’s display and learn typical patterns for your foods.