Freeze Dryers and Freeze Dried Food (Part 2)

[Herdy]

Any one that is a bit more technical than me got any ideas, 

I went to bed last night and forgot to shut the drain valve, woke up this morning to a room full of oil vapour mist, not splashed up on the top of my drying table though, as has happened at other dumb person moments.

Anyway, since then I have not been able to pull a vacuum, I have tried draining the oil and cleaning out the whole cover etc, even though it looked clean and I had done this only 2 batches ago.

I have tried a couple of times for about 35 minutes and it won't get off xxx.

Do you think I have stuffed the machine. 

Or any ideas what to try next.

[Kerry Beal]

I'd send an e-mail to HR to ask their opinion.

[Canon4me]

I am planning on freeze drying some home grown sliced beets tonight. Can you overlap "slightly" the produce in the trays in an attempt to get a little more in them?

Also, do most of you use the automatic setting for the freezing and drying or do you manually set it for when it is convenient for you to deal with the product?

Edited August 20, 2015 by Canon4me (log)

[Kerry Beal]

As long as the total thickness is not too much - you'll be fine.  i usually freeze between 9 and 12 hours and dry for 12 - changing the drying time once i figure out when it's going to finish.  

[Kerry Beal]

Latest batch - started Tuesday evening, freeze cycle finished around 8 am. By the time I headed off to bed it hadn't entered the drying cycle - I hadn't set the drying cycle to 12 hours so it was at the default 5 hours. When I woke to a screaming child at 4:30 the beeper was going - so I went down and reset to dry for another 5 hours and crawled back into bed. Short of time while heading out to a funeral this am - I just dialled it up so it would finish around noon. Everything perfectly dry.

 

 

Okra

 

 

2 1/2 dozen raw eggs 

 

 

Dill

[Herdy]

Any one that is a bit more technical than me got any ideas, 

I went to bed last night and forgot to shut the drain valve, woke up this morning to a room full of oil vapour mist, not splashed up on the top of my drying table though, as has happened at other dumb person moments.

Anyway, since then I have not been able to pull a vacuum, I have tried draining the oil and cleaning out the whole cover etc, even though it looked clean and I had done this only 2 batches ago.

I have tried a couple of times for about 35 minutes and it won't get off xxx.

Do you think I have stuffed the machine. 

Or any ideas what to try next.

All fixed, HR sent me some ideas and it seems the Power Flush a couple of times sorted it out, Happy happy.

[Herdy]

Does anyone else feel the need to stop and defrost during a cycle, I have had a few things mainly Berries that go on and on and never seem to finish so I stop and defrost and there is a lot of Ice, and even after the second  reset there is always still Ice touching the trays.

 

Cheese, Apples and Bacon and a few others, I have not had to do this but berries seem the worst, mostly Mulberries and those that fit this type, have been taking over 40 hours even with the defrost.

[Deryn]

Quite a number of people have talked about defrosting mid-cycle - some have it down to a science using hair dryers or heaters so they can get the load back on within minutes, not hours. Read this entire thread and you will find that is sometimes a good strategy. Some things too just should not be dried with others (or they should be dried in smaller quantities) because they, with a higher water content, can cause a problem drying other lower water content foods within what would normally be their cycle time. All part of the learning curve which we are all still going through.

[Canon4me]

I have a question about draining oil from my pump........

That screw is very hard to get at unless you lift the pump up by the handle or have the pump sit way up off the surface of whatever you have it parked on. So...........what do you guys have your pump sitting on to el fate it high enough to get at the drain screw? And does it sit on that all the time and is there a danger of it vibrating off and the pump tipping over? Thanks! Pictures of the pump sitting on it are welcome also!

[Kerry Beal]

Back when I was using the oil pump - I would lift it up and put it on the front of the cart when I needed to remove the oil. I have a piece of penrose drain (think rubber tubing) that I used to provide traction when I was opening the drain plug. I put something under the back of the unit to tilt it forward to aid drainage. 

 

No pictures sorry.

[Mr. Mike]

WOW... a LOT has been covered here since I last posted...a LOOOOoooOOOnG time ago.  There a lot of good new questions and results posts and a few of the typical "old" question topics... oil issues... icing-de-icing and food not dry enough,  how many lbs can you dry. etc...

 

For those that have not scrolled thru the previous early pages... Along,  long time ago. I still rememger  (sounds like the beginning of Americam Pie.. lol) when I put a list together. 

 

A "UL" list   my .. Mr. Mike "Universal Laws" of freeze drying list... i.e.  My experiences from the early days when there weren't many people that owned any FD's.  This should ring a few bells for the older members and maybe enlighten some new combers.

 

http://forums.egullet.org/topic/150588-freeze-dryers-and-freeze-dried-food-part-2/#entry2005558

 

I need to post more..sorry for being out of touch...I have been REALLY swamped with my business and haven't been doing much drying with my machines.

 

Hope this helps.

 

Mr. Mike

Edited August 26, 2015 by Mr. Mike (log)

[Deryn]

Nice to see you back, Mr. Mike!

[Kerry Beal]

Gotta say with the scroll pump removing the issue of oil changes from the equation I am more likely to fire up the HR to FD a batch of something. And of course all the fresh stuff at the market calls out that much more loudly.

 

 

Basil 

 

 

Three trays of ripe peaches

[Herdy]

I have a question about draining oil from my pump........

That screw is very hard to get at unless you lift the pump up by the handle or have the pump sit way up off the surface of whatever you have it parked on. So...........what do you guys have your pump sitting on to el fate it high enough to get at the drain screw? And does it sit on that all the time and is there a danger of it vibrating off and the pump tipping over? Thanks! Pictures of the pump sitting on it are welcome also!

The hose is just a bit too short for me to pull it to the edge of the shelf it is on under the drier without undoing it, so I found a small wooden box  in my shed about the same dimensions as the pump, which I pop the pump up on to drain.  I take the pump outside onto a small table to do a power flush and a remove the cover clean though.  I was going to just leave it on the box, but thought it might not be too level and I might not get the oil level correct.

[Chocolot]

Stopped in to HR today. They have expanded their operation! Matt showed me their newest product that hasn't been announced yet. (He gave me permission to mention). It is a smaller machine with a smaller price. He said it holds 3/4 the amount of their first machine and will retail for about $3000.

 

 

He also showed me the new touch display that is going on all machines. It even gives a reminder to close the drain valve:) He said if the door isn't latched properly and the machine won't create a vacuum, it will shut itself down. They are listening and improving!

 

 

[Deryn]

Thanks, Chocolot. Snazzy colour! It must not be as deep as the current one (?) then if it only holds 3/4 the amount because the number of shelves looks the same.

It is a bit sad that they have to have the machine tell us to close that drain valve. You would think we grownups would not have to be spoonfed (but sadly I know we often do!)

Any word on when the newer version may be ready for release? I won't take this to the other forum I belong to since 'I' don't have permission - but I am sure some there who could not manage the larger size might be interested.

Edited September 2, 2015 by Deryn (log)

[Kerry Beal]

I want one about 1/4 the size to take up north with me.

[Chocolot]

Thanks, Chocolot. Snazzy colour! It must not be as deep as the current one (?) then if it only holds 3/4 the amount because the number of shelves looks the same.

It is a bit sad that they have to have the machine tell us to close that drain valve. You would think we grownups would not have to be spoonfed (but sadly I know we often do!)

Any word on when the newer version may be ready for release? I won't take this to the other forum I belong to since 'I' don't have permission - but I am sure some there who could not manage the larger size might be interested.

 

They are in production now. I'm sure he wouldn't mind if you post. The entire machine is smaller, including the shelves.

[Deryn]

THanks, Chocolot. Did you take those pics? If so, can I use them and how do you want them attributed?

[Chocolot]

THanks, Chocolot. Did you take those pics? If so, can I use them and how do you want them attributed?

 

Yes, I took them with permission from Matt.  No attribution necessary.

[TonyC]

I have a question about draining oil from my pump........

That screw is very hard to get at unless you lift the pump up by the handle or have the pump sit way up off the surface of whatever you have it parked on. So...........what do you guys have your pump sitting on to el fate it high enough to get at the drain screw? And does it sit on that all the time and is there a danger of it vibrating off and the pump tipping over? Thanks! Pictures of the pump sitting on it are welcome also!

 

I made an inexpensive pump stand that allows one to easily drain the oil.  I used 2" x 8" lumber for the side legs and 1" board on top.  I used 1 1/2" decking screws to secure the top to the 2'x8" sides. Painted it black.  I built it tall enough to allow me to place a cup or small pan under the oil drain and allow it to completely empty before removng the cover to clean it up.  It is sturdy and stable, and simplifies the messy oil change issue.

 

Here a picture of my simple pump stand.

 

Re: Ice Buildup

As ice builds up inside the unit I defrost it...usually about 10 hours from when the pump starts running ( an d10 hours from the last defrost if the food still isn't dry.  After turning the unit off I use a fan to defrost and remove the ice.  I can defrost the system and have it back up in running in about 15-20 minutes.   Food trays are placed in an adjacent freezer and the tray frame is laid on top of the freeze dryer while I defrost.  I note the temperature within the freeze dryer before I shut it off, and when I turn it back on I allow it to reach 10F lower then what it was when I stopped it, then I manually kick it over to the drying cycle.  Usually the cooling cycle is an hour or less.  

 

Benefits are less water vapor in the pump & faster drying times.  Drawbacks are you need to defrost it once a day. Sometimes twice for extremely wet foods.

 

Another benefit is that I now go up to 20 cycles on the same oil before changing it.

 

Re: Freeze Drying Peanut Butter

We use natural peanut butter only....  has anyone tried freeze drying it.  If so could you share your experience. 

 

I am tempted to try but a little nervous about doing it.  I don't want a butter type explosion  (except with peanut butter) all over the inside of our freeze dryer.

 

Tony

Edited September 7, 2015 by TonyC (log)

[TonyC]

I've noticed a small problem with my FD door over the last few weeks.  I tend to open the door all the way up when I am defrosting or inserting/removing food trays.  After several months I started to see a scuff developing on the bottom of the door near the hinge.  I thought that maybe I had overlooked it when I purchased the FD, so I kept an eye on it and noticed that it was becoming more pronounced.  I took a closer look and noticed that the door, when fully opened, rubbed at the top of the FD at the edge, and more importantly the bottom of the door rubbed up against the hinge frame assembly.  The door is designed to slide about 1/4" (the hinge hole is oblong) to allow positve seating on the black vacuum ring gasket.  When the door was extended all the way out it never rubbed, but if it slid in that 1/4", the top would hit, and the bottom of the door would scuff.  The scuff was 1/8" wide and 1 1/4" tall when I finally decided to do something about it.

 

I corrected this by adding two soft clear silicone adhesive feet, at the top of the door and the adjascent FD edge.  When the door opens fully, these two contact each other (You can find them at your local home improvement box store).

 

 

The one located on the bottom is the more important to add as it stops the scuffing from ocurring on the door when it is fully opened. Using a flash while taking the picture allows the scuff to be seen.  It is invisible under normal light now but it was very pronounced until I buffed and polished it out.

 

 

I also had to replace the black rubber grommets in the door hinge.  They were falling apart and my hands were blackened when I removed them.  Luckily I had the correct size on hand!

To be fair, our FD has run non stop since we purchased it 9 1/2 months ago, and I consider these to be wear items - although teflon inserts would wear much better here.

 

Re: Thermometer Placement

 

I use a $10 AcuRite thermometer from Walmart to keep an eye on FD temps.  I place the display between the door and plug insert at the base of the gasket. I place the outdoor sensor under the tray stand.  It registers down to -51F.

 

Edited September 7, 2015 by TonyC (log)

[rotuts]

I have a question for the FD crowd :

 

its about reducing wine for  ......

 

the usual Apps ion cooking.

 

can your systems take

 

1 frozen wine   ( deeply frozen )

 

2 remove both the water and the EtOH ?

 

that would be nice .

 

Ive always thought that one does need to reduce wine to concentrate the flavor

 

perhaps remove the EtOH or not

 

but in doing so, one has to loose some of that Wine-Ey flavor

 

that's why you buy wine  :  Wine-Ey flavor

 

other wise, you might get Lowest Shelf  Vodka or everClear.

[Kerry Beal]

I have a question for the FD crowd :

 

its about reducing wine for  ......

 

the usual Apps ion cooking.

 

can your systems take

 

1 frozen wine   ( deeply frozen )

 

2 remove both the water and the EtOH ?

 

that would be nice .

 

Ive always thought that one does need to reduce wine to concentrate the flavor

 

perhaps remove the EtOH or not

 

but in doing so, one has to loose some of that Wine-Ey flavor

 

that's why you buy wine  :  Wine-Ey flavor

 

other wise, you might get Lowest Shelf  Vodka or everClear.

 

Not a success as I recall from here.

[Brent]

Hi all, 

 

Discovered this site this weekend, and spent much time reading the 747 previous Freeze Drying posts.   Thanks to all for sharing -- I've learned much.  We have been HR owners for about a year -- love it, btw -- but only into "24/7 mode" for about the last three months.

 

As was inevitable (though unanticipated), I've scaled the learning curve about vacuum pump maintenance, (aka water drain-offs, oil changes, power flushes, and pump cover disassembly and cleaning.)  We've followed the instructions given by HR.  Like many, I was surprised to see the buildup of gunk (I believe that's their official term  ) in the pump, and the effects of the accumulated water.

 

Having recently completed my third anti-gunk teardown, I thought there has to be a better way.  It seemed like filtering the oil might help, so at first I tried the obvious:  coffee filters and filtering through dense cloth.  Short story:  Not worth the effort and the mess.

 

It occurred to me that the solution might be to use an automotive oil filter.  (There is a reason they call them "oil filters", after all.) 

 

The problem is, a car's oil filter operates under pressure, and has the intake and outlet on the same side of the filter.  There is no flow "through" in the sense of what goes in the top comes out the bottom.  Hmmm...

 

I finally came up with a solution that would work around that, and here it is:  (--don’t laugh, first impressions are often misleading).  

 

 

 

The oil goes in the can at the top, passing into the filter below, filling it.  The overflow then goes out of the filter and is caught in the container beneath. 

 

The can and the filter are linked by a threaded pipe, as shown here: 

 

 

The one "gotcha" I encountered in making this is that a typical car oil filter attaches with a 3/4x16tpi threaded pipe.  I could find no such pipe anywhere.  My solution was to use instead a 3/4x16tpi bolt, and then drill a hole through it.  Fortunately, I have the equipment to do that, but most probably wouldn't.  Even then, bolts are hard material, and I dulled two drill bits getting it done.  

 

The "disk" that the can and filter rests on is just a board with a 2" hole in its center, cut in half.

 

So now I change (or perhaps I should say, “recycle”) the oil after every batch.  I immediately drain the oil while it's still hot and when the water and sediment particles are mostly still suspended.  

 

 

Someone's bound to ask about the water, which of course the filter wouldn't exclude, although it would probably accumulate in the bottom of the filter and not pass into the container.  I solve that problem by letting the drained oil sit a while, so that the water and sediment will settle, then I put it in the freezer until the water freezes.  The water & heavier gunk stay behind, while the oil still flows nicely.  Here are pictures showing the oil with the water frozen at the bottom, and the ice and sediment that remain after the oil is poured off into the filter.

 

 

Here's a before/after comparison of oil after one batch (previously new oil used for one batch of mushrooms -- yummy, btw) and the same oil after being run through the filter: 

 

 

A couple of other points:  There are obvious and easy improvements that could be made, such as using a container with a dispensing faucet (think of a lemonade jar, for example).  Also, for the technically savvy, auto-mechanic-type person who may be wondering about it, there is an anti-backflow seal that has to be removed from the oil filter, but that can be removed by cutting through it and pulling it out with needle nose pliers, which is easily done.

 

So far there has been a noticeable difference in the cleanliness of the oil, and hopefully that will be true for the buildup of "gunk" as well.  I imagine pump disassembly and cleaning will still be needed, but hopefully not nearly as often, and with a little luck, it won't be nearly as "gunky".    

 

Sorry for such a long post (especially my first one!)  Hope this is helpful to someone!

 

Brent

Edited July 18, 2016 by Brent (log)