The Freeze-Drying Thread

Britesea

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Ok, I never got around to taking pictures this weekend, but I'm going to start this thread anyway.

The first thing I'll do is describe how freeze-drying works. The food gets taken down to a super cold environment in a vacuum. Then the chamber warms up a bit. Since water cannot be liquid in a vacuum, it sublimates into a gas and leaves the food. When the sensors read that nearly all the water has left the food, it goes into a final drying period and then voila! you have a freeze-dried product.

For anyone interested in getting a freeze-dryer, I have to tell you there's a fair amount of maintenance that goes with it. The oil in the vacuum pump needs to be changed regularly since water vapor and food bits end up getting into the pump. Occasionally it needs to be power-flushed, and I read that you also occasionally have to take it apart and clean off some part that can get gunky even with all the oil changing and such. So if you want something you just run and then forget about it, maybe a freeze-dryer is not for you.

It can only handle about 10 lbs of food at a time, and depending on what it is and what the ambient temperature is, it can take anywhere from 24 to 48 hours to freeze dry things. You cannot freeze-dry high fat things like butter (you just end up with butter all over the inside of your freeze-dryer) or high sugar, like jam (the sugar binds with the water so it doesn't go away).

BUT... it's the best form of preservation there is currently, for preserving the nutrition of your food. The texture is basically the same as previously frozen. And when it's been properly protected from light and air, freeze-dried food should last 20 years or more. It weighs next to nothing compared to fresh food; and if you store it in mylar or sealed plastic bags, you don't have to worry about a big mess if there's an earthquake.

Currently I have a load of golden plums in there. I'll take pictures and give you a review on their taste and texture tomorrow.
 

NH Homesteader

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Interesting. I had no idea they required that much maintenance. That might put me in the "not for me" gang, but interested to hear/see more
 

Britesea

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I pulled out the plums today image.jpg and they looked great! Trying them straight from the freeze-dryer, they are crunchy and light, a bit more acidic than they were fresh. Rehydrated, they are a little mushy, like frozen ones would be but I imagine they would be fine in baked goods or maybe even to make more jam? They took about 1 1/2 days, because I didn't have the plums frozen when I started the process. Having the food already frozen shortens the time.

I have another batch of these to do, waiting in the freezer. OR, I could freeze-dry the fire-roasted bell peppers I'm working on. I tried freeze drying the peppers just plain, which most people apparently do, but I wasn't pleased with the slight toughness of the skins when I rehydrated them; so I'm fire roasting some to see if that takes care of the problem.

Should I do the peppers or the plums? Enquiring minds want to know!
 

frustratedearthmother

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Peppers! So, after fire roasting are you going to peel off the skins? Or is that the point of fire roasting, lol.
 

Britesea

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I did peppers! 3 trays of fire roasted -
fire roasted peppers.jpg
and 1 tray of blanched
blanched pepper.jpg


They both turned out fine. The blanched ones have a skin that is no tougher than on a fresh pepper, and it takes a whole lot less work than the fire roasting, so I think that's what I'll do with most of my peppers. Of course, the fire roasted peppers have that extra layer of flavor, so I may still do some occasionally.

Tomorrow I will do the rest of my plums, and then I'll start on some of the meat in the freezer.
 

Britesea

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Well, I have several more market bags full of bell peppers and 1 of jalapenos to take care of. I'll just blanch and freeze-dry the bell peppers; the jalapenos will be fire roasted and put into salsa, which I usually can but I'll try freeze drying some salsa and see what happens.
 

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