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Curing chamber problem

Posted: Mon Sep 17, 2012 14:38
by atcNick
I'm testing out my curing chamber with different temp and humidity settings. After doing a test run at 68F and 88% humidity (for fermenting conditions) I set it back to 57F and 75% humidity. I cant get it below about 85% humidity after a full day being at that setting.

I have a frost free freezer as a curing chamber which ran at 40-45% humidity before I installed a humidistat and humidifier.

The only reason I can think of why humidity is not going down is that it's been raining here for the last couple days and humidity is 99% outside. Would higher outside humidity cause this problem even in a frost free freezer? My curing chamber is located in my garage.

I have not drilled any holes into the freezer for the purpose of venting/fanning air out, I dont think that would help anyways since the outside humidity is higher.

What do you curing chamber experts think?

Posted: Mon Sep 17, 2012 17:35
by Baconologist
Takes a while for the humidity to adjust sometimes, especially without much air exchange.
What's the RH in the room?

Posted: Mon Sep 17, 2012 17:41
by IdaKraut
Try a pie tin filled with any one of the following desiccants: calcium chloride (Damp Rid or Dri-Z-Air or sidewalk deicer which lists only calcium chloride), rock salt or kosher salt, or clear kitty litter pearls (silica, also found in desiccant pouches when you buy items that are meant to stay dry).

Rytek Kutas, in his book, also mentions using sodium acetate crystals which will maintain a steady 75% humidity.

I simply use Crystal Clear Litter Pearls brand of cat litter with good results.

Posted: Mon Sep 17, 2012 17:49
by atcNick
Baconologist wrote:Takes a while for the humidity to adjust sometimes, especially without much air exchange.
What's the RH in the room?
Im not sure. The freezer is in the garage, the outside humidity is 99%. I took the humidifier out a couple hours ago to see if the humidity would go down. Its down to about 75% now. I have a back up humidity sensor. Just a regular round analog one with a needle and its showing 62%. Hmm...

The backup is near the top of the freezer, the one with the digital readout has the sensor installed about the middle of the freezer.

Is this a normal variance? 62% vs 75%?

Posted: Mon Sep 17, 2012 18:29
by Baconologist
Can the hygrometer be calibrated?
You really do need one that's of good quality and can be calibrated.

Posted: Mon Sep 17, 2012 18:55
by atcNick

Posted: Mon Sep 17, 2012 23:56
by Cabonaia
Nick -

I have the same advice as Baconologist. Give it time.

I wired a light bulb socket into my curing fridge and put it on a dimmer switch. If it gets too humid in there, I turn it on low. It does try to warm things up a bit, but then the fridge turns on and fights back effectively, because the bulb is not very hot when it is on low. Meanwhile, the humidity goes down. I'm not sure this makes sense, but that's what happens. You have to pay attention if you do this - it's a short term fix if the humidity gets way out of control.

Posted: Tue Sep 18, 2012 00:32
by ssorllih
The light bulb on a dimmer is a very good choice because you can choose the rating of the light bulb and the brightness.

Posted: Tue Sep 18, 2012 00:58
by atcNick
Cabonaia wrote:Nick -

I have the same advice as Baconologist. Give it time.

I wired a light bulb socket into my curing fridge and put it on a dimmer switch. If it gets too humid in there, I turn it on low. It does try to warm things up a bit, but then the fridge turns on and fights back effectively, because the bulb is not very hot when it is on low. Meanwhile, the humidity goes down. I'm not sure this makes sense, but that's what happens. You have to pay attention if you do this - it's a short term fix if the humidity gets way out of control.
So the purpose of the bulb is to warm up the freezer so the freezer kicks on, allowing the auto-defrost to work? Or does the heat somehow help lower the humidity?

Posted: Tue Sep 18, 2012 02:49
by uwanna61
Nick
All good advice from the members. Keep in mind the humidistat is designed to control a small room, what we are using it for is an even smaller space. With that said, I will run my humidistat at a slightly lower setting than what the set point would be. Example, I have had days in the summer when the outside humidity is high and the humidity would be up in the cabinet. If my set point is at 75% and the actual is 85% in the cabinet, I will drop the set point down to say 65- 68% to better control the humidity in the curing cabinet. I also have a 40 watt bulb setup in my curing fridge and it works well stabilizing the temp & humidity, definitely use a dimmer switch. I had a 100 watt bulb in the beginning and wow it would heat up. Also, a small computer fan running as low as possible may help with air circulation.
Good luck
Wally

Posted: Tue Sep 18, 2012 03:57
by Cabonaia
atcNick wrote:So the purpose of the bulb is to warm up the freezer so the freezer kicks on, allowing the auto-defrost to work? Or does the heat somehow help lower the humidity?
Hey Nick - I turn it on because it creates dry heat. I use a converted fridge, so there is no auto-defrost at work here. The heat just helps lower the humidity. It does it fast - sometimes too fast. You have to keep your eye on it and dial it in.

I set up the bulb/dimmer in order to provide heat when I want to incubate before drying. But several times I turned on the light when I opened the fridge so I could see better. Then I closed the fridge and walked away without turning off the light. THAT is how I discovered the drying effects of a light bulb. :mrgreen: Nearly ruined a batches that way.

Posted: Tue Sep 18, 2012 04:48
by ssorllih
This is where the relationship between absolute humidity and relative humidity comes into play. Relative humidity is always a percentage on the amount of water vapor that the air can hold at a specific temperature. At 100% humidity we are on the verge of having fog. But if the air temperature rises then the relative humidity goes down. The absolute humidity may remain the same in terms of grams of water vapor per cubic meter of air but because the air is warmer it can hold more water vapor before fog forms at that particular temperature. It is possible to have fog form at 80° F but not at all likely unless someone is pouring hot water out on the ground or there has been a rain shower on a very hot day and the pavement in the parking lot is heated up in the sun and the evaporating ground water is showing a thin fog in the cool air after the storm.

Dryer breath

Posted: Tue Sep 18, 2012 17:16
by el Ducko
Maybe it would help to think of it this way:
(1) light bulb heats up air in box, causing refrigerator cooler to switch on.
(2) evaporator coil gets cool, cooler than incoming air dewpoint, condensing moisture from incoming air. Moisture runs off as a liquid, and is discarded.
(3) cool air continues into box, where it mixes with warmed air. The result has a lower dew point (moisture content) than the original air.

Result: Drier air. Dryer air. Both. Clearer? :roll:
If you thought sausage microbiology was fun, wait 'til sausage thermodynamics!
"Coming to a [meat smoker] near you."

Posted: Wed Oct 17, 2012 18:16
by atcNick
I may have already posted this. Im having an issue with my curing chamber that I havent seen anyone else mention on this or other forums. Im getting pooling water at the bottom of the curing chamber (stand up freezer). It's a frost free model but it seems like the water from the humidifier is condensing on the floor of the freezer. So much so that it ends up leaking out and onto the garage floor. Its really only an inconvenience but I cant seem to figure out why I and no one else is having this problem.

Posted: Wed Oct 17, 2012 19:03
by ssorllih
See line 2 of Ducky's explaination.