The Freeze-Drying Thread

[Britesea]

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.

 

[Britesea]

I've been FD'ing cuts from about 18 lbs of beef round- I did cubes for stews, strips for stir-fry or things like beef stroganoff, and several 1/2" thick steaks cut into decent portion sizes for things like swiss steak. They all look great, but I haven't actually cooked with any of it-- gotta do that soon.

Today I put in the last of the beef strips (2 trays) and the other 2 trays have leftovers from misc meals- Chicken Carbonara, Moqueca de Camaroes (brazilian shrimp stew), and Thai Ground Beef.

We had turkey this weekend (it was meant for Thanksgiving, but I bought it too early and it was thawed already); today I'm going to shred the rest of the meat off the carcass and freeze most of it for FD after setting aside enough to make a casserole tonight and turning the carcass into soup.

I'm having so much fun with this thing!

 

[Britesea]

Fanfare please....

I finally tried some of the freeze-dried meat! I took a couple of round steak pieces, rehydrated them with beef stock and made pressure cooker Swiss Steak. It took a good 6 hours to rehydrate; next time I'll try my vacuum sealed marinating trick, to see if the vacuum sucks the water into the meat a little faster. Browning the meat took only a couple of minutes, and the pressure cooking was 30 minutes, though I think I could have gotten away with 20 minutes. The meat was beautifully tender; you would never know it wasn't fresh.

 

[Britesea]

My freeze-dried salsa worked out great! This 1 quart jar is what I have of the 1 1/2 quarts I started out with. It takes about 1part salsa to 3parts water to make a decent texture. I also did some mixed frozen veggies that were sitting in the freezer, a package of boneless skinless chicken thighs (raw) and 1 lone pepper-crusted steak. I should have cut the steak into thinner slices, because the 1 inch thick cut was too thick- I've had to put a whole bunch of extra time into the final drying time on it. I will let you know how the chicken turns out later this week when I use some up for dinner.

 

[Britesea]

The only reason I could afford this appliance was because I got a nice chunk of inheritance money that I hadn't planned on. I still find my dehydrator and canners and the freezer useful however- so I will be using all methods, depending on what I'm preserving. Each one has its pros and cons.

 

[Sammster]

Done!

 

[Britesea]

I did peppers! 3 trays of fire roasted -

and 1 tray of blanched

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]

Tomatoes are AWESOME dehydrated. You can grind them up into a powder and use them with different amounts of water for tomato paste, tomato sauce, tomato juice, even instant tomato soup. I tried freeze-drying them, but the amount of time and small space available decided me to keep dehydrating them instead; although I still need to see how the freeze-dried ones turn out rehydrated- would they have enough texture left to be a usable substitute for fresh in winter salads?

We got an entire pork loin (about 9 lbs) from Cash N Carry today- $1.55 a pound. I've got it in the freezer for just long enough to make it easy to slice, then into the freeze-dryer. Should make some lovely chops!

 

[Britesea]

Started the pork in the freeze dryer at 3:30 today. We'll see how long it takes to dry. The only prepping I did was to pre-freeze the chops to shorten the freezing cycle.

@sumi the meat needs to be kept away from oxygen, moisture and light for maximum storage time. I use my vacuum sealer and the special mylar bags made for it (regular mylar doesn't work because both inside surfaces are smooth, so it can't suck the air out). Once they've been vacuum sealed in there, they should be good for as long as 25 years (if kept in a cool environment). Once you open a bag, you can store anything you don't use in a ziplock bag, as long as you use it up within a month or so. I will only store a smallish number of pork chops per bag so it's easy to use them all up within that month.

To use it for cooking, you can rehydrate it in water (or broth or a mixture of water/marinade for more flavor!). From what I read, it's best to do this in a ziplock bag, with just enough water to cover; let them sit for about 50 minutes and then cook. They apparently take less time to cook than fresh meat, so watch carefully. Oh, I also read that they might have a weird "cat-food" type smell when you first open the bag, but that goes away with rehydration.

 

[Britesea]

Been ages since I posted in here... I need to do that again. I haven't stopped freeze drying, just got out of the habit of posting it.

My carrots came out of the freeze dryer this morning looking (and tasting) wonderful. I blanched them first, just like I would for freezing, and it preserved the color. The first time I tried freeze-drying carrots, I just cut them up and processed them raw; the color faded out and they looked very unappetizing.

I'm getting ready to pack up all the onions I freeze dried over the last few days. I bought a 50 pound bag and chopped them up and tossed them in. They take only moments to rehydrate. I have them in plastic ziplocks right now- two trays fills a gallon sized bag. I 'm thinking I will squeeze most of the air out of each bag, then put the bags into a bigger mylar bag to protect them a little more. I don't want to do a hard vacuum pack because they crush very easily.

I've become very fond of Denver Omelets made with FD onions and peppers. The vegetables rehydrate in less than 5 minutes and then I add them to the egg and voila! I could use FD ham as well, but that would take thinking about it the night before so I could get it rehydrated overnite.

I made a beef stew a using some of the freeze dried beef cubes in the instant pot. I pressure cooked it first, but the meat still seemed a little tough, so I switched to the slow-cook, threw in the vegetables, and gave it 3 more hours and that did the trick. It was tender and flavorful.