Off Grid Home Forums Technical Discussion Freeze drying food Re: Freeze drying food


The problem with the vapor trap I bought is, it doesn’t have a vacuum gauge.

this is the one I bought: I have yet to use it for anything, except freezing some peaches.

So you can freeze a jar just smaller than a mason quart, but there is no way to tell if you are maintaining vacuum when you start the “thawing” process.

The triple point of water is the point where ice either changes to vapor or water. With normal pressure, ice changes directly to water, it is above the triple point.

Below the triple point or under 6 mbar of vacuum, the ice cannot melt, it goes directly to vapor and is removed.

The only thing the vapor trap or flexi-dry actually does is remove the moisture from the vacuum line. It is to keep your vacuum pump from being ruined by the excess moisture.

All that is needed for freeze-drying is a strong vacuum and the “thawing” of the food. I stress “thawing” because it doesn’t really thaw. The food gradually warms and the energy liberates the moisture from the food.