Three ways to remove moisture in your freeze dryer's drain line

Ensuring there's no moisture in the drain line is crucial before starting a new freeze-drying batch. Moisture in the drain line can hinder the chamber from reaching the desired pressure level, which is essential for optimal freeze drying.

We provide three methods for removing moisture from the drain line, allowing you to choose the best option based on your situation:

1. Q-Tip Method: Use Q-tips to absorb and remove moisture directly from the drain line. This method is simple and effective for minor moisture removal.

   

2. Air Pump Method: Use an air pump to blow out moisture from the drain line. This method is the most efficient but requires removing the shelf from the chamber. Make sure you have the drain valve open before you turn on the air pump to blow moisture off the drain line. 

   

3. Vacuum Function Method (Recommended for a freeze dryer with the industrial pump): For larger models like our Mega Freeze Dryer, frequently removing the shelf to clean the drain line can be cumbersome and potentially risky due to the wires connected to the shelf.

   Here’s how to effectively use the vacuum function method:

   • Step 1: Close the valves for both the vacuum hose and drain line.
   
   • Step 2: From the main screen, access the functions menu and open the ball valve and turn on the vacuum.
   • Within one minute of turning on the pump, you should see the door being pulled inward and you see a 'black ring' on the door. If this does not occur, it may indicate an issue with the chamber's airtightness. Potential problems could include an open vacuum valve, an improperly closed drain valve, a misaligned ball valve, or an issue with the door seal. Adjust the door first if you suspect the door is not sealing correctly.
     
   • Step 3: Wait about 10 minutes to allow the chamber pressure to effectively drop.
   • Step 4: Disconnect the drain hose from drain line. Open the drain valve to allow the vacuum to pull moisture from the drain line into the chamber.
   

Although a small amount of moisture in the chamber is acceptable for freeze drying regular foods ( as the freeze dryer only starts the drying process when the chamber and shelf is very cold which ensure there's no liquid form inside), it is crucial to thoroughly remove moisture when preparing candies. If you opt not to use the air pump and prefer not to frequently remove the shelf, consider the following after using the vacuum function method:

• Additional Cleaning for Candy Batches: If you are preparing to dry candy, after cleaning the drain line using the vacuum function, use a Swiffer duster or similar tool to wipe down the space between the shelf and the chamber wall to ensure all moisture is removed. This extra step helps maintain the ideal conditions for candy freeze drying.

By choosing the appropriate method and following these steps, you can maintain the integrity of your freeze drying process and ensure the best results for a variety of foods.