A brief explanation of the process in the machine
- Pre-cooling phase– About 15 minutes (before food goes in) during which the inside of the machine cools down to between 40F and 0F. This ensures that frozen food put in the machine stays frozen.
- Freezing phase– This is a deep freeze to between -30F and -50F. When the machine has determined that the food is the correct temperature, the pump will kick on.
- Drying phase– This is where freeze drying happens through a process called sublimation. The ice crystals in the food are turned into a gas and removed. The vacuum pump creates a negative pressure and draws the gas out of the food while it remains deeply frozen. It keeps cell structures of the food intact.
- Extra dry time phase– Once the machine determines that no more moisture is being removed it will kick into the extra-dry time. It could technically stay in this phase forever and not harm the food because it can’t be more than 100% dry. Once all the moisture is removed, it can’t get ‘more dry’. But if there is moisture the machine is not detecting, such as hidden inside seeds, or deep in thick food, this phase helps ensure the food really IS fully dry.
- Defrost phase– The machine warms up to between 80F and 125F to melt the ice that has collected inside the machine (moisture pulled from the food), which drains out. Once the food is at or above room temperature, there won’t be any condensation from the difference in the outside temp and inside the machine temp. It also allows for checking dryness by feel. If there is ANY coolness inside the food it still has moisture in it. If there is anything other than brittle, crunchy dryness, the food isn’t done and will need to go through the extra drying phase again.
Use A Freeze Dryer 