Freeze Drying

[Bacpacker]

I'm loving seeing the results and all the things you are trying. We are seriously thinking about getting one. This just gives us some up front info and will shorten our learning curve. I'll follow the thread as long as you want to share.

 

[Double R]

I was only asking to see if you can shorten the first phase for a
Pre-frozen
Mostly liquid

Batch.

Ben

You can set it for less. I haven’t gotten that far yet but did watch how to do that. I noticed that the new software no longer asks pre frozen vs thawed.

 

[Double R]

Ok. Drainage issues resolved we hope. When we defrosted the chamber it flooded out the front. It’s supposed to drain out the bottom drain tube in the back but it seemed to have “issues” doing that reliably. We can see why many online recommended putting the front up slightly. We leveled the unit when we set it up via the top and sides on the outside. We should have checked in the chamber a bit more. Also think how we have the drain run needs to be changed.

Time for the next batch.

Tomatoes sauce that was expiring. Using these molds they are supposed to fit nicely in wide mouth pint jars once freeze dried. 4 pucks is one can of sauce. Since we no longer buy sauce and just can our own we thought this would be a good way to preserve it and learn with it.



Beef bone broth from what was left from the trays batch yesterday. Figured we’d try this instead of refreezing and thawing again to fill a tray. Wasn’t expecting the batch to freeze dry so quickly so refroze it in the molds.

1 puck of the remaining bone broth from the last batch same as above. 2 pucks of tomato paste same as above and the paws are beef bone broth. For years I filled the molds and freeze them for easy dosing for my old dogs. They take up a lot of space in the freezer so I’m trying to take up extra tray space with them. Hope to no longer use the molds and strictly freeze dry and add to their meals in “powder” form. It rehydrated in their meals fine tonight.

 

[Double R]

After all the delays we decided we’d make sure it worked well before we bought another pump etc. Also make sure we were happy with our pump choice. That is definitely the plan though. Have to research still if buying the pumps is best through them or other places. They do give you a 10% discount offer on your next purchase after the drier has shipped. May use that for a second pump and extra supplies.

*Just an update for accuracy of information- the discount code you get an email for you have to contact them for the actual code and it’s not valid on pumps or driers.

 

[Double R]

Tonight’s update: I was gone most of the afternoon. Unfortunately the drier said it was done and it definitely wasn’t.

Set it for another 2 hours of dry time.

Time for bed so just added 12 hours more. Will check again when I get up. Won’t be 12 hours but just in case I can’t get out to check as soon as I get up. Don’t expect it to take even 1/2 that time.
The bone broth paw prints and the bone broth pucks were done after the extra 2 hours so I pulled them and packaged them up. Could hear them crackling when I pulled them absorbing moisture from the air.


An observation on the tomato sauce pucks. After the 2 additional hours the tops of a few “tested” dry. This would be about 1/2 way through from the top down. I flipped them over and they weren’t dry. So I flipped them all before adding the additional time. Very glad to have the tester.

 

[Bacpacker]

Good info on the results.
What kind of tester do you have? Almost reminds me of a moisture meter for drying wood in a kiln

 

[goshengirl]

Yeah, that tester makes me think of what my husband uses for testing firewood.

Oh my gosh, those pucks in a jar are awesome. I can a lot of bone broth for our dogs, so I can totally relate.

 

[Double R]

Good info on the results.
What kind of tester do you have? Almost reminds me of a moisture meter for drying wood in a kiln

That's exactly what it is. Literally a wood moisture tester. Got it on Amazon. Several people on YouTube uses this one for testing their freeze dried stuff so grabbed one to try.

Yeah, that tester makes me think of what my husband uses for testing firewood.

Oh my gosh, those pucks in a jar are awesome. I can a lot of bone broth for our dogs, so I can totally relate.

Nice. It’s a wonder thing. I don’t expect these to last long being used by us and the dogs/cats so I didn’t think using a Mylar was worth it. I got the molds specifically for using jars to store stuff. Also to make ready meals in jars. Once freeze dried the pucks fit perfectly in wide mouth jars.Still working out if I need to put a piece of parchment or something in between each piece or not.

 

[Double R]

After another 12 hours dry time the tomato pucks still aren't done. Some are (left them in anyways) and most aren't. 6 more hours added. I think the tomato is so dense making such full pucks is making it hard for it to dry. Worst case I will break them in half allowing the centers to dry easier. We're at 37 1/2 hours so far.

 

[Neb]

Thickness is definitely a factor.

Thinner is faster.

Since they are pre frozen can you put them on a screen to let moisture out the bottom?

Ben

 

[Double R]

Thickness is definitely a factor.

Thinner is faster.

Since they are pre frozen can you put them on a screen to let moisture out the bottom?

Ben

Good idea! I’ve seen some people put paper towels or parchment underneath certain things which helps suck up fats etc. Since these are now mostly dry I could put something underneath now for sure. I did see a website that sells racks that fit the trays

 

[Double R]

Just went out and cut them in half. Hope that wasn’t a mistake. Don’t want powder to get sucked into anywhere it’s not supposed to go. Cut them on a seperate cutting board to allow the least amount of powder on the trays. Definitely still cold/moist in the center of a lot of the pucks. Set for more time. That should definitely take care of it now. Will powder them and store them as a powder from now on. I do remember several people online saying the powders rehydrate far faster and smoother than in chunks for a lot of things. Learning curve

 

[Neb]

Just went out and cut them in half. Hope that wasn’t a mistake. Don’t want powder to get sucked into anywhere it’s not supposed to go. Cut them on a seperate cutting board to allow the least amount of powder on the trays. Definitely still cold/moist in the center of a lot of the pucks. Set for more time. That should definitely take care of it now. Will powder them and store them as a powder from now on. I do remember several people online saying the powders rehydrate far faster and smoother than in chunks for a lot of things. Learning curve

That should help.

Not to get too deep into material science but...

How fast you can get the water out depends on the material properties of what you are trying to dehydrate. If it is mostly water it behaves like water. If it mostly something else it behaves like something else.

I spoke in a previous post about the sublimation that takes place in the drying phase and will not go into that aspect now. But what needs to be understood is the sublimation takes place when there is an interface between the solid water and the gaseous water.

That is why drying starts from the outside in. The outer surface in contact with the air can readily sublimate. The interior not so. The water in the center has to move to the surface to sublimate.

How long it takes to let the water in the center to move to the surface takes us back to an Algebra question using the formula

D=RT

Where

D= distance (from the inside to the surface)
R= rate (how fast the frozen water moves)
T= time required to move 5he distance

Mention of the Random Walk omitted

D
Distance is the thickness (1/2) of your thingy

R
How fast the water moves. More on this below.

T
Time required to get the water on the inside out. This is what you can control in phase 3.

_____

R
Rate discussion

The process that transport the water from the center to the surface is osmosis. Most of us has seen osmosis in real life.

Drop a drop of food coloring in the center of a paper towel you will see it spread via osmosis. Simple stated osmosis is...

A high concentration of something will move toward a low concentration.

High concentration in the center low on the surface.

Mention of the Random walk omitted

How fast the osmosis works is dependent is dependent on temp. Higher the temp faster the osmosis. This is where we understand what is happening in phase 3.

The instructions you posted indicated the temp is cycled up and down (check me),to squeeze the last part of the water out.

While keeping the temp down and
Pressure down

The temp is cycled to move the osmosis along in sprints to let the water sublimate.

Nuff said.

Ben

 

[Bacpacker]

Professor Ben
You do a great job breaking stuff down and explaining it. Very good Job

 

[Double R]

@Neb Thats so cool

 

[Double R]

Pulled the last puck. 1/2 Still wasn’t done. Packaged up the rest already so just rehydrated the whole thing to try.
Got two 3/4 full pint jars from 5 3/4 cans of tomato sauce.

Made great tomato paste. Took about 1/2 hour for it to complete rehydrate smooth. If it had been powdered like the rest is it would have rehydrated faster. Probably should have used warmer water as well.

Added more water to make tomato sauce. Tasted just like it came out of the can.

Unfortunately ran into an issue vacuum sealing the jars. The powder is so fine it gets sucked into the vacuum pump. So one jar is sealed and the other I dumped into a Mylar and heat sealed.

While defrosting with a fan we ran into the same problem as before. Figured it out now that we had time to really look into it better while it was happening. Turns out using a big fan put to much air in the front while allowing the ice farther back to block the drain. We will be getting a clip on fan. Most seem to attach it to the upper shelf and that would make sense so the air is pushed to the back more than the front which allows the drain to do its job. Will try that next.

 

[Neb]

...
Very good Job

Yup!

Even God bragged bout how good he was.



Ben

 

[Double R]

By the time I got these in they were basically thawed. Here’s the next load.

 

[Double R]

Ok. I have a confession to make. There’s no tray weights of the finished product. It was a free for all the second we opened the door

22 hours. The machine said it was done at 16 hours. However the grapes were chewy. Watermelon and pineapple we’re definitely done. I’ve seen a lot of online comments about people always getting chewy grapes. Noticed the times on videos that people got crunchy ones. To me they seemed like they were still moist so I added 6 hours. Sure enough. Nice and crispy. Moisture meter read 6 at 16 hours and 0-2 at 22 hours. A few were slightly moist but I am not planning on long term storage after seeing the free for all when the door opened. When the excitement ends I’ll do more for long term storage and will make sure they are zero moisture.


Absolutely delicious. Extremely sweet. With the grape taste and the crunch with a slight chew at the end it’s like a grape candy.
watermelon reminds me of watermelon flavored freeze dried marshmallows like the ones that used to come in cereals.

 

[lilmissy]

Can you send me a link to the meter? I need to get one Of those.
Fyi, be careful with the tomatoes, those little seeds is what causes lots of moisture

 

[Double R]

Can you send me a link to the meter? I need to get one Of those.
Fyi, be careful with the tomatoes, those little seeds is what causes lots of moisture

General Tools MMD4E Digital... But there’s other options as well. This is just one I saw multiple freeze drier people use.

 

[goshengirl]

I have to admit, with the Auguson Farms thread and their skyrocketing prices (in some places) on freeze-dried food, I couldn’t help but think that the value of a home freeze-drier has just gone up.

 

[Double R]

@goshengirl I was thinking the same thing. Last I heard the medium freezers (which after research does more than the large over time) was 6 weeks out after ordering before shipping. With more people ordering I am guessing it will only get longer. Add shortages on parts etc and who knows what will happen.

 

[goshengirl]

@goshengirl I was thinking the same thing. Last I heard the medium freezers (which after research does more than the large over time) was 6 weeks out after ordering before shipping. With more people ordering I am guessing it will only get longer. Add shortages on parts etc and who knows what will happen.

The medium is exactly the one I was drooling over this afternoon....

 

[Double R]

The medium is exactly the one I was drooling over this afternoon....

That’s what we decided on. Between the dedicated plug/fuse etc and the fact that the times take longer for not much more product it appeared from our research to be more cost efficient to get the medium and run “more” loads with less vs less loads with more which took more time. Not sure I’m explaining that well but hopefully you get what I mean.

 

[goshengirl]

That’s what we decided on. Between the dedicated plug/fuse etc and the fact that the times take longer for not much more product it appeared from our research to be more cost efficient to get the medium and run “more” loads with less vs less loads with more which took more time. Not sure I’m explaining that well but hopefully you get what I mean.

I believe I understand your meaning. And I appreciate your research!

 

[Double R]

Next batch: Some left over onions in puck molds. 3 trays of bell peppers from the garden. Pre frozen

 

[Double R]

Finished time 27 hours.

These are delicious as is. Kept some out to rehydrate and see how they turn out. The onions are very strong but really good to eat as is. The bell peppers were also good but didn’t turn out as strong as I thought it would. Could definitely use both as “chips”.

 

[Double R]

3.0 watts when sitting idle.

1 hour into freezing

 

[Neb]

View attachment 73607
3.0 watts when sitting idle.
View attachment 73608
1 hour into freezing
View attachment 73609

Thank you for the energy cost info.

If those numbers are low enough The Princess may be hers sooner than planned.

Ben