Troubleshooting Guide
What Should I Do If the Power Goes Out During a Freeze-Drying Batch?
Quick Answer
What you do depends on the stage of the cycle, how long the outage lasted, whether the food stayed frozen, and the food type. There are no absolute food-safety guarantees, so follow the manufacturer's restart guidance and use good judgment.
What This Usually Means
The machine stopped mid-cycle, and the food is sitting in a chamber that is no longer under vacuum or refrigeration. The safe path depends on how long the food thawed and what kind of food it is.
Check These First
Work through these before anything else. Most problems are found here, and every check is safe to do.
- How long the power was out.
- Whether the food remained frozen through the outage.
- The stage of the cycle when power was lost.
- Whether the machine resumed automatically or needs a manual restart.
Likely Causes
Possible causes include, ordered from the simple and common to the more technical.
- 1 The food thawed during the outage and the cycle stalled.
- 2 The machine needs a manual restart, and the manufacturer's restart procedure was not followed.
- 3 The outage happened early in the cycle, before much drying occurred.
- 4 The food type is high-risk if it thawed, such as raw meat, poultry, seafood or eggs.
- 5 Repeated outages or unstable power during the batch.
What to Do
- 1 Avoid unnecessary chamber opening so the food stays as cold as possible.
- 2 Inspect the food's condition before deciding anything.
- 3 Follow the manufacturer's restart guidance for your machine.
- 4 Refreeze when appropriate, per the manufacturer's guidance and the food type.
- 5 Be conservative with raw meat, poultry, seafood, eggs and other potentially hazardous foods. Freeze drying does not sterilize food, and if you are at all unsure about safety, discard rather than risk it.
What Not to Do
- Do not repeatedly open the chamber to check the food.
- Do not assume frozen food is automatically safe if it thawed during the outage.
- Do not restart the machine without checking the manufacturer's procedure first.
When to Stop
If the machine will not restart correctly or shows an error after power returns, contact the manufacturer.
Stop immediately if you notice any of these:
- The machine will not restart and shows an error after power returns.
- Visible electrical issues such as sparks, arcing, or exposed wiring.
- A burning smell from the machine or the pump.
- Unusual grinding sounds or smoke from the machine or the pump.
Related Problems
These guides cover problems that often show up together with this one.
Related Guides
Learn the background behind these checks in the beginner guide and the food encyclopedia.