Instructables

Home Freeze Dryer (Lyophilizer)...can it be done?

I love freeze dried fruits. However, they are super expensive. Does anyone know how to make a freeze dryer at home? I have no idea if it would even be possible or cost effective.

Kidvid314652 years ago
You could start with two stainless steel food service full pans sealed top to top w/ a gasket and bolts with a sealed copper tube to exhaust the air from a fish aquarium air pump on the INSIDE of the pans and leave the whole arrangment running in the inside of a refrigerator running at about 32 degrees. It should work theoretically since the water shouldn't condensate in the pump and the pump shouldn't overheat when run continuously ( not to mention it's in a refrigerator ). But I would take while ( good quality aquarium diapham pumps make about 15 psi tops ) and the results I suspect would be somewhere between real freeze dried food and very dry dehydrated food in consistency.

You need to pull a 0.06 ATM vacuum to freeze dry. Aquarium pumps don't even come close, and being able to generate 15 PSI at 1 ATM doesn't mean anything when generating a vacuum. Also, the food itself doesn't need to be cold, there needs to be a cold coil that pulls the moisture out of the air (it needs to be about -50ºC/-58ºF).

dtklein7 months ago
Mr Holland's acetone recommendation using acetone is dangerous. Freeze drying at home relatively easy, and can be accomplished with a deep freeze (or a party cooler + dry ice), a method of creating a partial vacuum (food saver is better than seal-a-meal) and a moisture/oxygen absorber.

There is a really good walk-through at:
http://www.youtube.com/watch?v=UeIxBDIfowE

If you want more techniques, there are written instructions at:
http://www.wikihow.com/Freeze-Dry

I just had an idea! make a cooling bath out of dry ice and acetone, then put your food in it and let the acetone slowly replace the water. Once you're done, put it in a vacuum chamber until all of the acetone boils out and voila, no more water! You'll have to get used to the taste of acetone and the occasional tremors, but hey, people do essentially the same thing with cannabis and butane...
Two of the main differences between freeze dried and dehydrated is the quality of the food texture when it's reconstituted and the nutritional value left in the food after the process is complete. Freeze dried maintains 100% of it's nutritional value where dehydrated only maintains 80%. The texture of freeze dried is much closer to the original plant than dehydrated. Many to most restaurants use freeze dried vegetables in their salad bars and the general public don't seem to notice. I'm looking for a personal freeze dryer myself.
Have you had any luck? The only small freeze dryers I've found so far are over $5,000, way out of my budget. I've tried finding used ones online without much luck.
Hi Ali! do you have any reference to that $5,000 freeze dryer?
Search on alibaba.com it's your best bet.
timgineer2 years ago
Freeze drying (and vacuum drying) is a whole different ball game than an American Harvest Food Dehydrator (which I have 2 of and use very frequently).

Freeze drying is very difficult. To retain texture the food must be flash frozen (think liquid nitrogen). Vacuum drying however, can achieve a possibly superior result and doesn't require freezing.

Following that a very strong vacuum (think oil filled vacuum pump) must be pulled to get the very cold ice to evaporate. Vacuum drying doesn't require quite as strong a vacuum.

The next problem is how to keep water out of the vacuum pump. The water (from the drying food) turns the oil into an emulsified sludge and that is really hard on vacuum pumps.

There are 2 options, either build a condenser (think about -60 deg C or colder, more liquid nitrogen) or use a diaphragm vacuum pump (that doesn't use oil).

Diaphragm pumps that pull the required vacuum are hard to find but available.

A condenser could be a simple as running a piece of metal pipe through some liquid nitrogen or possibly a dry ice-alcohol slurry (it gets close). Keep in mind the collected water will eventually block the pipe and will need to be drained some how.

The next trick is to find a good container that can withstand the vacuum, possibly pass in some radiant heat and not excessively off gas. Stainless steel, rubber, wax and glass work well. Plastics generally do not. Keep in mind a perfect vacuum is on the order of -15 psi. A canning jar works rather well but is small.
Dr.Bill4 years ago
I've done it with a frost free fridge.
did you end up with a quality product that was easy to reconstitute? What did you freeze dry?
jillpettis4 years ago
I found this: http://www.ehow.com/how-does_4794057_freeze-drying-home.html
Haven't tried it though.  In the comments a poster says this only works with frost free freezers.
What about just freezing your product in the fridge and putting it in a Bell Jar with a vacuume pump.  Free vacuum pumps exist in every discarded refrigerator. . .  If the defrost is too slow pipe the vac to the bell jar/pump into your fridge or freezer.
spandox5 years ago
I beg to differ. One "advantage" that a freeze drier has over a dehydrator is the structure of the finished product. Because the water is sublimating from ice to vapor it leaves the end product often more airy and crispy (there is air where the water used to be - and the surrounding tissues are completely dry and often brittle). it is completely different experience snacking on freeze-dried peas verses chipping your teeth on dried peas. There needs to be a vacuum chamber with a running vacuum pump and a condenser chamber to trap water. In essence the water in the frozen food is required to keep a "partial vapor pressure" around it. The water sublimates and then is either drawn out by the vacuum pump or condensed in the chamber that is kept colder than drying chamber. In order for this to work you need to draw a vacuum and have the food very near but just below 0. Once you think you have most of the water you can let the drying chamber get to just above zero for awhile. I hope this helps you build one.
rich_moe5 years ago
Freeze-drying is just a process to remove moisture and liquid from fruit/vegetables to decrease bacterial growth. Rapid air-drying or dehydration works just as well and does not require the expense or the hardware. You can purchase small heat/fan combo dehydrators from an appliance store, or you can do what I saw on the Food Network Show 'Good Eats', with Alton Brown do. He used a simple 20" box fan, some cheesecloth, a furnace filter, and some bungee cords to make a simple dehydrator. He called it the "Supersuck 5000". It just moved air across the items, wicking away the moisture. I still like my American Harvest Food Dehydrator, though. There are some really nice DIY dehydrators here on the instructables website as well.
For the energy conscious, self-reliant types, there's a great article from Mother Earth News that included instructions and drawings for building a solar food dehydrator. It was in the August/September 2006 edition, or you can click the following link and view the article online.

Have fun.

George

https://www.motherearthnews.com/Do-It-Yourself/2006-08-01/Build-a-Solar-Food-Dehydrator.aspx
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!