DIY desiccant for moisture control?

[Yoss]

First post! hope its in the right place...

When I built a fermentation chamber out of an old chest freezer one of the things I noticed was all the condensation. I was afraid of eventual mold problems so googled around and found a few options. Disposable desiccants that you have to keep buying and "rechargeable" ones (like the eva-dry) that get mixed reviews and seem to be poorly designed. I eventually went with the Eva-dry 500 in my 7 cubic foot chest freezer. I haven't had to recharge it yet so I'm keeping my fingers crossed that it will recharge properly and not burn my house down.
When I saw this article I remembered all the disapointed people from the Amazon reviews so I followed the link to the white paper. (Warning science ahead) Link
So after reading about it:

• Its already a food safe chemical with the FDA (some of the other reactants and side reactions may not be)
• It seems to outperform most other desiccants, especially at lower relative humidities.
• It can be "recharged" without excessive heat. They put a vacuum on it at about 95 C, but maybe it would recharge without the vacuum if you just threw it in the oven at a slightly higher temperature?
• bulk reagents are available through the internet or chemical supply company.

The only problem I see is the pressure, you would need a pressure vessel that can handle 3 bar (43 psi). Perhaps a corny keg? I dont know how well a stir bar/stir plate will work with that, maybe you could get away with occasional swirling.

I could see someone trying this for a DYI project and throwing it in one of those arm and hammer fridge boxes. It probably wouldn't be any cheaper than just buying what is on the market now, but not everyone does DYI for the cost savings. I don't really have the time to try it out but if anyone here does please let me know how it works out!

 

[m3n00b]

I've been using damp rid in my chest freezer and still get a ton of condensation.

 

[JonathanS]

I use a combination of 2 Eva-dry dehumidifiers and the small size open plastic container of damp rid in a 13 cu ft keezer. I have to change out the damp rid at least once a month and recharge the eve-drys every 2 months or so.

Still get a minor amount of ice build up on sides and bottom of freezer but its managable. I also used two 12v computer fans mounted on the lid (blowing down) to keep air moving around in the keezer.

 

[Stealthcruiser]

Major, heavy Science with big words!

What do it say?
What is the chemical?

 

[marinosr]

This article was interesting, Yoss. Thanks!

I don't think you'd have a problem finding a vessel that can handle 3 bars of pressure. A coke can at room temperature is at around 2.5 - 3.5 bars, depending on your definition of room temperature. A growler with a luer lock valve could do this quite nicely.

I'm sure recharging the dessicant can be done at normal pressures... they just applied a vacuum to dessicate it as thoroughly as possible so as to test the max. moisture capacity.

A fan blowing in your cooler can help cut down on condensation by reducing the temp difference between the evap coil and the air.

 

[Stealthcruiser]

WHEW!
Waded through it again, and let me see if I have this straight:
They were using the pressure vessel to "form" the Magnesium Carbonate, yes?
Are you gathering that if this Magnesium Carbonate were available over the counter, (re: "Upsalite),it could be used free standing as an easily rechargeable desiccant?

I can see "dehydrating" it under the temp and vacuum, or at an elevated temp alone.

In it's application for a Homebrewer, you would not need it in a pressure vessel, to use as a desiccant...........Is that correct?

Thanks!

 

[limulus]

I have the large size tub of DamRid and the EvaDry 500 in my 7cu ft keezer. I still get lots of condensation and now I have some mold. That means I have to empty the whole thing and sanitize it. I had no problems until last month when the humidity came up.

 

[Stealthcruiser]

Did some more searchin', seems it was developed by accident, or so the text says.
Discovered / created at Upsala University, in Sweden, and they have since formed a company.
Check out:

www.disruptivematerials.com

 

[pjj2ba]

We use this in the lab. drierite

A bit pricey, but infinitely reusable. There are likely cheaper sources. Basically it is anhydrous Calcium Sulfate - something many of us put in beer!

 

[Yoss]

WHEW!
Waded through it again, and let me see if I have this straight:
They were using the pressure vessel to "form" the Magnesium Carbonate, yes?
Are you gathering that if this Magnesium Carbonate were available over the counter, (re: "Upsalite),it could be used free standing as an easily rechargeable desiccant?

I can see "dehydrating" it under the temp and vacuum, or at an elevated temp alone.

In it's application for a Homebrewer, you would not need it in a pressure vessel, to use as a desiccant...........Is that correct?

Thanks!

Yes, the pressure vessel is just used to form the gel substance that is later dried at normal atmospheric pressures.
It sounds like it could be used free standing, maybe in a container with a fine mesh top or side that would allow moisture to be absorbed.