Freeze Dryers and Freeze Dried Food (Part 2)

[Kerry Beal]

Any foodsaver with a port will do - then get one of these.

[Deryn]

You could also just put an O2 absorber in the jar and skip the vacuum part. That is best if you are using mylar too.

Canon - How did the green beans come out?

Edited August 4, 2015 by Deryn (log)

[Kerry Beal]

 

Not very exciting to look at - rhubarb puree. Needed a few more hours after the first run through so left it overnight.

[Deryn]

Bravo!

So the new pump works fine and is much quieter, the rhubarb dried ok (even if it took a bit longer - wonder if things not cycling had anything to do with that - or just that you set it up as a very short cycle anyway?), and you won't have any water in the oil because there is no oil - and no oil to change either? If that is the case, I am going to see about getting mine retrofitted too in the foreseeable future. Thanks, Kerry ... for doing this experiment for us all.

Edited August 4, 2015 by Deryn (log)

[Kerry Beal]

Works fine, quieter, no oil. I think that the extra time might not be actually extra - with the old pump I wouldn't have ever considered taking stuff out after 7 hours - that's always been too short for anything I've done.

[TonyC]

Re OIl spray when valve left open

Today I left the drain valve open accidently... the first time since I added the oil catch can.   The can did its job and I had no oil outside the pump at all!  The pump ran an hour with the valve open before I caught it.  The oil was foaming a bit and the pump was loud.  I closed the valve and the pump quieted down.

 

Re Oil Change intervals

I got 20 cycles out of the last oil before it was necessary to change it.

 

Re Kerry's Pump

I'll be watching Kerry 's post to see the ramifications of her pump change.  No oil is a big plus as is the quiet factor.

 

Re Pump Noise

My pumps starts off quite loud, quiets down once I see vacuum, then gets a little louder as it runs through the cycle.  I found that if I can keep it cool (within 10F of  ambient temps) that the pump is much more efficient.

 

Quick question:  Has anyone noticed that fruit tends to flatten and dry out almost like it does in a dehydrator?  I have placed fresh cut 1/4" sliced peaches on the trays and found them shrunken at then end of the FD cycle as if they had dehydrated on several occasions.  I wonder if I am doing something wrong.  Here in central North Carolina the temps in my garage do tend to get into the mid 90's with the FD running, and I have taken to using a fan to keep things cooler in hopes of fixing the problem.  I have noticed that FD temps don't get as low in the summer as they do in the winter.  I saw -50F in the winter, best I've seen in the summer is -39F.

 

I have had the same experience with Pineapple and Cantelope.  Curious thing about the Cantelope, the Cantelope in the lower two trays held their size and dried as expected, while the upper two trays the cantelope looked more like chips... there was also movement of the slices as if they popped like popcorn.  I found one slice outside the tray and several others layered on top of others and the adjacent space empty.

 

If you have successful settings for peaches, cantelopes, and pineapples I'd love it if you could share them.

 

Tony

[Kerry Beal]

I've had some things pop - gummies and such - I think they weren't as well frozen. Or it might just be the nature of gummies. But I do recall something about things that aren't well frozen expanding when they heat under vacuum.

 

Hubby has suggested that after I close the hatch when starting up that I unplug the vacuum from the back of the machine - plug it into the wall and run it until the door has clearly sealed shut. I've been doing this with the new pump so far - it ensures that I have a good vacuum right at the start. So I feel confident that when the vacuum comes on when I'm out of the house that there is no danger of a poor vacuum (of course I'm no longer worried about oil spray - but I still want the unit evacuating well).

[Deryn]

That flattening out thing definitely sounds like a heat issue, Tony. And heat rises so perhaps the top two trays are getting more heat overall and it is just enough, early enough in the process, that they are dehydrating slightly before they freeze-dry. On the other hand, could there be anything wrong with the heating elements/wires under the trays? Could they be 'overheating' those two trays maybe? Or could the controller not be shutting off the heat when it should?

I have no idea what the issue is obviously (I haven't experienced that problem) but I thought I would throw out a few questions for you to think about - although you are probably correct and it really just is about ambient summer heat in an un-airconditioned space.

[Canon4me]

You could also just put an O2 absorber in the jar and skip the vacuum part. That is best if you are using mylar too.Canon - How did the green beans come out?

The beans turned out great. My second batch was sliced beets out of our garden and that turned out great. I am really opening my eyes to the potential of this machine. I originally bought it for WSHTF scenario. With the idea of never needing to eat this stuff unless of a dire emergency, but I have since changed my mind to one of possibly rotating this food and eating it regularly or at least semi-occasionally. Since my wife and I eat pretty much organic, I will probably buy only organic if we are going to rotate through it. If I wasn't going to rotate it and use it just for SHTF, then I wouldn't be buying organic. Right now I run it strictly on default time. When I acquire more confidence I might alter the times, but that will take awhile. I'm still new with this machine and have to gain experience.

Where do I buy parchment paper for this? Is it available sized for these trays? And lastly, is parchment paper the same thing as waxed paper and is that ok to use? Thanks much!

Edited August 5, 2015 by Canon4me (log)

[Deryn]

Parchment paper may be called a different name where you live. Perhaps 'baking paper'? Up here it is sold on rolls or pre-cut packages sized to fit on cookie sheets. I either tear off some from a roll or cut one of the pre-cut ones in half and that fits quite well on our trays.

Waxed paper might work too since so little heat is generated by the FD process.

Edited August 5, 2015 by Deryn (log)

[Kerry Beal]

Batch 2 with the new pump. Freeze cycle for ∼9 hours, stage 2 was a little less than 24 hours I think. I had the  dry stage set for 9 hours originally - when I woke this am it was around 4 hours into the cycle so I reset so it would finish around 6 this evening when I got home from work. 

 

 

Caramel, chocolate, pecan slice cream

 

 

Wild blueberries - President's Choice brand.

 

 

Ice cream sandwiches - chocolate ice cream filled. 

[Chocolot]

Anyone do whole cranberries? How did they do?

[Kerry Beal]

I haven't so far. Don't know if I have any in the freezer I could add to the next run.

[TonyC]

Little unrelated....can anybody make a recommendation for a vacuum pump/food saver to suck out the air on mason canning jars for which I will store some of my freeze dried food?

 

Not sure if you know this but you can use your freeze dryer to pull a vacuum on your jars.  Harvest Right has a write up on it.

 

• Basically you remove the heated tray rack from the FD
• Install a tray upside down in the bottom
• Place your jars on the tray with canning lids installed and ring loose
• Close the FD door - no need for black insulation plug
• Plug your vacuum pump into an outlet
• Close the drain valve
• Turn on the pump and let it run until you 10-20 minutes (my pump takes 20 minutes to reach 0mTor)
• Turn off pump and open drain valve
• Your Jars should be sealed.

 

After telling you all this I prefer to pull a vacuum with a small inexpensive vacuum pump.

I purchased a small vacuum gauge and the food saver lid adapters.  I pull at least 29" of vacuum on each jar.

Takes less than 30 seconds per jar. 

 

I wrote about it in detail in an earlier post in this thread...  may have been in Part 1.

 

Tony

[Canon4me]

Kerry, just curious.....has HR given their endorsement or stamp of approval with the new pump you are using? I wonder why they didn't manufacture these with that pump to begin with?

[Canon4me]

TonyC, my Gamesaver Foodsaver Deluxe came yesterday and I will try it this weekend. On an unrelated question, is it important that the cycle completes during a time when you can deal with food rather than have it complete, for instance, in the middle of the night and sit in the unit for a few hours until you wake up in the morning? I have no way of predicting when a cycle will complete due to the food type, how I have it arranged on the shelves, moisture content of the food, etc.

[TonyC]

Canon4me,

Where do I buy parchment paper for this? Is it available sized for these trays? And lastly, is parchment paper the same thing as waxed paper and is that ok to use? Thanks much!

 

We buy our parchment paper from ifyoucare.com.  Here is the link

 

http://buy.ifyoucare.com/Products/Eco-Friendly-Baking-Cooking/If-You-Care-Parchment-Paper-70-sq-ft

 

My bride has perfected the tray lining process and can line them perfectly in under 20 seconds!  Here is how she does it.

 

1. She lays a tray down on the counter and unrolls, then cuts the paper 1"-1.5" longer then the tray.  She never measures, just eyeballs it.

   

    

2. Next she folds the edges up about 2"- 2.25" on each side

   

    

3. Next she flips the paper over and centers it on the tray folds side down

   

    

4. She then presses the paper into the tray.

   

    

5. Then starting from the center of the tray working out she creases the front and back edges simultaneously with her thumbs and fingers

   

    

6. When she reaches the end of the tray and creases the corners, the short edges crease automatically.  The tray is ready to be loaded.

   

We place meats, fruits, and veggies directly on this surface.  Also pour in thicker sauces and pastes ( tomato pastes, mashed potatoes, sweet potatoes, stews, and chili).  If the item is liquid such as beaten eggs, we freeze them in another pan with higher sides and once frozen place them in the tray.

 

The paper can be reused and we do if we have a batch of the same food going into the FD.  Right now we are FDing peaches, cantelopes, and other fruits locally in season.  The paper does become stiff and brittle after going through the FD.

 

This method saves paper and money.  We buy our paper 12 rolls at a time and I'm placing our 3rd order for 12 more rolls today.  

 

We store our FD food in our pantry, generally in mason canning jars. Once we had our pantry levels in stock, we rotate and eat our freeze dried foods regulary.

 

Hope this helps others in their FD adventure.

 

Tony

Edited August 7, 2015 by TonyC (log)

[Kerry Beal]

Kerry, just curious.....has HR given their endorsement or stamp of approval with the new pump you are using? I wonder why they didn't manufacture these with that pump to begin with?

Matt at HR seems quite interested in what I'm up to - he was very helpful when I initially approached him about what the specs of the pump would need to be. We've communicated several times since I fired it up and he continues to be very supportive and interested.

 

As to why they don't manufacture with this sort of pump - take a look at the price of these pumps new - it's just not on. They could not possibly put out an affordable product using a diaphragm or scroll pump that can attain the kind of vacuum required for freeze drying. A rotary vane pump can attain the vacuum and is reasonably priced.

[TonyC]

Are there any maintenance issues with the scroll pump?  I've seen rebuild kits for them, but I have no first hand working knowledge of them.  How long do they typcially last?  They are quite expensive!

 

Being quiet and no need for oil are nice benefits.

 

Will the pull the same level of vacuum?  Do they heat up as much as you original pump?

[Kerry Beal]

Don't know the answer to that one! Flying by the seat of my pants. 

 

I was worried that I might end up with a pump that required a rebuild right from the start - but appear to have gotten lucky.

 

It's quieter - don't know if I'd go so far as to saying quiet. When it's running in the basement I can still hear it in the two rooms that are above the room it's in. But I can work in my chocolate lab next to it without feeling like my ears are going to fall off.

 

This one can pull a great vacuum - and it does so very quickly. It gets warm. 

[TonyC]

TonyC, my Gamesaver Foodsaver Deluxe came yesterday and I will try it this weekend. On an unrelated question, is it important that the cycle completes during a time when you can deal with food rather than have it complete, for instance, in the middle of the night and sit in the unit for a few hours until you wake up in the morning? I have no way of predicting when a cycle will complete due to the food type, how I have it arranged on the shelves, moisture content of the food, etc.

 

I try to be home when I think my FD will complete it's process for several reasons.  First I don't like the food refreezing in the last 20 minutes of the final cycle when the pump shuts off.  If the food is cold and I pull it out in a hot humid climate, condensation immediately begins and the food will start sucking up that moisture.

 

Second, and more importantly to me, I don't like the pump shutting off before I close a valve that I have installed on the inlet of the pump.  When a standard oil based vacuum pump shuts off without a valve on the inlet side of the pump the air seeks to equalize throughout the system.  AIr will flow back up the vacuum hose into the food chamber.  It will flow from the atmosphere through the pump exhaust through the oil chamber out the pump inlet back into the the food chamber.  This brings very small amounts of oil vapor into the food chamber.  How much?  I don't know.  But any is more than I want in my FD food.  A statement here from me... This is my conjecture and conclusion... and we all know about opinions - we all have them.

 

This precaution is known in the refrigeration repair business as you do not want to contaminate the freon in the system with pump oil.  Valves are on the vacuum lines and on gauge sets to prevent just such a scenario from ocurring.

 

I may be making more if this issue than necessary, but I chose to err on caution. 

 

Here's a picture of the valve that I added to my pump. Adding the valve also allows me to easily isolate the pump, and open the drain valve to check the food dryness or ice build up without turning anything off.  After I check conditions in the chamber I simply close the drain valve, and open the pump valve and everything goes on normally other than having the FD drying timer reset.  I also changed the pump inlet ports to larger diameter.  All parts came from Lowes Home Improvement... under $20 total.

 

After having your freeze dryer for a while you'll start becoming quite good at estimating accurately when your FD cycle will complete.  We can judge pretty accurately now when a given type of food will be done and schedule around it or postpone / increase the drying time to meet our schedule requirements. Adding / substracting a couple of hours on the cooling or drying time to insure the machine stops when you want it to.  

 

    

Edited August 7, 2015 by TonyC (log)

[Kerry Beal]

Are there any maintenance issues with the scroll pump?  I've seen rebuild kits for them, but I have no first hand working knowledge of them.  How long do they typcially last?  They are quite expensive!

 

Being quiet and no need for oil are nice benefits.

 

Will the pull the same level of vacuum?  Do they heat up as much as you original pump?

Here's a discussion about scroll pumps - sounds like once a year maintenance is the usual.

[Kerry Beal]

Latest batch -

 

 

Mint that grows in my neighbours garden - the best place to get mint.

 

 

Tomatoes Provençal 

 

 

Little raspberries

 

 

Corn kernals - damn they're good!

 

 

[TonyC]

Recently received mangos from a friend in S Florida.  They were great!  We let them ripen up and tried freeze drying them.  He mentioned that the very small variety was quite fibrous, but FDing them seemed to take care of that issue. 

 

They turned out fantastic!  Both Tender and flavorful.  Mangos are great FDed..

 

We also wanted to try FDing Tuna Fish.  We puchased 4.5lb cans of Chunk Light tuna in water from Sams.  Two cans filled the 4 trays quite nicely.  The tuna FDed excellent as well.  The Tuna FDed very quickly.

 

We placed both in Mason Jars and pulled a vacuum to seal them.  Here's a sample of each.

 

[Deryn]

Fantastic, Tony. Thanks for the additions to my (things to) FD list. I have done fish before (and it came out great) but haven't yet tried canned tuna.

Edited August 15, 2015 by Deryn (log)