Filtering vacuum pump oil
Filtering vacuum pump oil is a part of owning a home freeze dryer. It is necessary to remove moisture and food particles from the oil through filtering. Oil from the vacuum pump should be filtered after every load. This helps to ensure a long life of the vacuum pump.
When you purchase a Harvest Right freeze dryer you will receive a filter like the one in the picture below. The Harvest Right filter is the one on the left. It works and does filter out the particulate matter. Unfortunately I found it to be poorly assembled and messy to use. The Brita filter on the right is what we now use.
The Harvest Right oil filter
If you look at the picture above you will see the Harvest Right filter on the left. Initially we used the HR filter that came with the freeze dryer. To remove the filtered oil you have to unscrew the lower lid and lift everything out of the bottom container. It will drip oil and needs to be placed on something to soak up any oil. We grew tired of the mess and having to assemble and disassemble the filter. Now we use the Brita filter on the right in the picture. It is discussed below.
Our Brita oil filtering system
While this system is what we currently use, the idea wasn’t our own. We borrowed the idea from a freeze dryer group and have adopted it for our purposes.
For our filtering system we bought a 10 cup Brita pitcher. These filtering pitchers can be bought new for around $25. For the bargain minded folks, try looking for one in thrift stores. I’ve seen people reporting to find them for just a few dollars.
This Brita filter uses toilet paper rolled up to remove food particles. The toilet paper rolled up will replace the charcoal filter. As the filter gets full simply replace the toilet paper. In the picture below you can see an example of the filter material needing replaced.
How the Brita filter is better than the Harvest Right filter
The Brita filter does not require disassembly to pour the filtered oil back into the vacuum pump. So long as there isn’t oil in the upper chamber you simply grab the pitcher and pour the clean oil.
A quick important note, the toilet paper filter does absorb some oil and you will lose some of it. You will need to have extra vacuum oil on hand to replace what is lost each time you add new filter material. Black gold vacuum pump oil is what we use and is one of the two brands recommended by Harvest Right.