Choosing a Lab Freeze Dryer: Bell-Jar or Pilot Model?

Freeze dryers fall into two broad groups: bell-jar (ex-situ) and pilot (in-situ). The right one depends on sample volume, process requirements and whether you plan to scale up.

How they differ

• Bell-jar freeze dryer: pre-freezing is done outside; the sample is placed under a bell jar and dried under vacuum. Simple, compact, and suited to small samples and routine lab work.
• Pilot freeze dryer: freezing and drying happen in the same chamber (in-situ), with programmable freezing and drying profiles. Suited to process development, small batches and scale-up studies.

How to choose

Situation	Suggestion
A few tens to a few hundred millilitres per run, method exploration	Bell-jar
You need to develop a cycle and want repeatable, recorded data	Pilot model
You will scale to commercial production later	Verify the process on a pilot model first
Vialed product or stricter handling needs	Pilot model; confirm the configuration

Common questions

• Must pre-freezing happen inside the machine? With bell-jar models it is done outside; choose an in-situ model when you need controlled pre-freezing in the chamber.
• How do I estimate throughput? It depends on moisture, fill depth and the drying profile, so a trial with your material is the safest way to confirm.

We offer a bell-jar freeze dryer and a pilot freeze dryer. If you are unsure, book a trial and compare with your own samples.