Home made freeze dryer / Lyophilization

[Hiltonizer]

I have a need to freeze dry some stuff, and apparently.... commercial freeze dryers aren't cheap.. and there isn't really anything on the interwebs about doing it at home.

I'm sure what I have in mind wouldn't be nearly as effective as a big expensive commercial freeze dryer, but it may just get the job done.

I'm figuring on getting a cheap used stand up freezer, popping an inch or two hole in the front door, and plugging it with a shop vac hose. Run the freezer with cookie sheets of stuff I need to freeze, once frozen, shut off the freezer and run the shop vac.

I think it might just be ghetto enough to work for fishing bait and a few other small items.

Thoughts?

 

[jkelly]

So you want to decrease the pressure in the freezer using a shop vac?

Respectfully,
jkelly

 

[theGringo]

I think it might just be ghetto enough to work ...

I'll add that to my list of "famous last words".

 

[EC1]

I have a need to freeze dry some stuff, and apparently.... commercial freeze dryers aren't cheap.. and there isn't really anything on the interwebs about doing it at home.

I'm sure what I have in mind wouldn't be nearly as effective as a big expensive commercial freeze dryer, but it may just get the job done.

I'm figuring on getting a cheap used stand up freezer, popping an inch or two hole in the front door, and plugging it with a shop vac hose. Run the freezer with cookie sheets of stuff I need to freeze, once frozen, shut off the freezer and run the shop vac.

I think it might just be ghetto enough to work for fishing bait and a few other small items.

Thoughts?

You Might want to take a look at this before you consider your path. Note the temperature needed, they are not normal freezer temperatures.

Good luck.


http://en.wikipedia.org/wiki/Freeze_drying

 

[Jedhed]

Could you use a dehydrator? Seems a lot more straight forward.

 

[glostamon]

I have a need to freeze dry some stuff, and apparently.... commercial freeze dryers aren't cheap.. and there isn't really anything on the interwebs about doing it at home.

I'm sure what I have in mind wouldn't be nearly as effective as a big expensive commercial freeze dryer, but it may just get the job done.

I'm figuring on getting a cheap used stand up freezer, popping an inch or two hole in the front door, and plugging it with a shop vac hose. Run the freezer with cookie sheets of stuff I need to freeze, once frozen, shut off the freezer and run the shop vac.

I think it might just be ghetto enough to work for fishing bait and a few other small items.

Thoughts?

Things that make you go ...

 

[zeppelinfromled]

I hate to be pessimistic, but I have my doubts that it will work. But I've written this post anyway to see if I can be of any help.

A lyophilizer does not typically cool the item and vacuum it at the same time. When I was doing lyophilization for work (chemistry lab), we froze the item completely using liquid nitrogen, and then put it into the lyophilizer. The lyophilizer was just a way to put a very strong vacuum on a sealed container. So it sounds like you have the right process in your set up.

You need to make sure that the vacuum is strong enough (a lot of commercial vacuum pumps can't get down to a low enough pressure to really dry it out). You also need to make sure that your container is air tight, and that it won't collapse under a vacuum.

I think that there are two problems that you'll run into (maybe just one). The freezer needs to be air tight, including the hole that you cut into it. That's fairly easy to accomplish. Once a vacuum starts to be created inside, it'll pull everything tighter. The potentially bigger problem is that your shop vac might not be strong enough to pull enough of a vacuum.

Two other things that I would suggest, if possible. The first is a release valve. If you have a freezer with a vacuum inside, and you want to open it - good luck. A valve to let air back in will be necessary and it's probably a lot easier than disconnecting your vacuum pump. Second, fight the urge to check on it all the time. You don't know exactly how long it will take, but I would bet that it will be measured in days, if not more.

 

[MA_Shooter]

I think that there are two problems that you'll run into (maybe just one). The freezer needs to be air tight, including the hole that you cut into it. That's fairly easy to accomplish. Once a vacuum starts to be created inside, it'll pull everything tighter. The potentially bigger problem is that your shop vac might not be strong enough to pull enough of a vacuum.

Two other things that I would suggest, if possible. The first is a release valve. If you have a freezer with a vacuum inside, and you want to open it - good luck. A valve to let air back in will be necessary and it's probably a lot easier than disconnecting your vacuum pump. Second, fight the urge to check on it all the time. You don't know exactly how long it will take, but I would bet that it will be measured in days, if not more.

We have a lyophilizer unit at work for handling various solids....the post above identifies two huge problems. The shop vac does not provide adequate vacuum (you need millibar pressures, or lower - such as from a rotary vane pump) and even if it did, you would have to use a thick-walled glass/SS vessel to maintain that pressure. Don't worry about the condenser (LN2 trap), that's the least of your problems. Sorry....but McGyver would be proud!

 

[Hiltonizer]

Thanks for the input all.

I'm neither a physicist, chemist, or mechanical engineer... but it was an interesting theory.

 

[jenlynn724]

It would be a waste of a perfectly good shop vac..lol Very inventive though..

 

[tblount]

I agree with others that you'll need more vac than a shop vac will provide. If I were trying this... and I may experiment because I've done a lot of home projects ( http://perfectflyer.com/tbindex.htm ) I would refer to the youtube video how a guy used an automotive AC compressor to create a powerful vacuum.

I would setup a container like a one gallon or larger glass jar INSIDE the deepfreeze and keep the vacuum on it, with the produc inside. It would need a pin hole to allow in dry air so the water vapor will go out into the vacuum system. I would simply put the deep freezer on a timer and allow it to freeze and thaw about once every 24 hours.

My understanding of freeze drying is to get all the water (in the product) frozen, then under high vacuum, thaw it so the ice goes directly from solid to vapor... then remove the vapor (cloud). The process has to be repeated several times. A normal deep freeze may not come on and freeze fast enough --- so the most "tricky" factor is probably the timing of the off cycle --- so that the thaw period is very short.

It would probably work better just to take the jar out of the deep freeze while it thaws and keep the deep freeze as cold as possible for quicker refreeze.