Planning (Vacuum Chambers)

There will be a need for 2 vacuum chambers.  One will contain the food to be dried. One will serve as a cold trap for deposition of water before reaching the vacuum pump.  I am using stainless steel vacuum chambers with glass lids.  These are commonly used to degas resins and epoxies used in woodworking projects.

The amount of food that can be freeze dried in one cycle is limited by the size of these chambers.  As water sublimates, then deposits in the cold trap, the cold trap fills up.  We cannot rely on the cold trap filling up evenly or completely.   For this reason, the cold trap is a limiting factor of the amount of food that can be freeze dried at one time.

We can get an idea of the mass of water that will be removed from the food imply by weighing the food.  We know that we cannot remove more water than is in the food.  If we freeze dry 25 pounds of food, we can be sure we will not remove more than 3 gallons of water since 3 gallons of water weighs about 25 pounds.

I can easily scale up the capacity of the freeze dryer if needed by adding more chambers for food and more cold traps in the freezer.