# Air flow in curing chamber



## Apophis13 (Apr 19, 2020)

Hi All

New to the forum and to curing(not cured anything yet). I recently got a fridge to try my hand at building a curing chamber. I understand the basics and have read quite a bit of the information out there. I have a temperature and humidity control (InkBird)with a humidifier and a dehumidifier.  The one thing I am a bit confused about is the airflow and changing of air in the chamber. It seems like replacing the stale air is important and some people just open the door every couple of days while others set up a fan to suck the air out. My idea is to create a hole in the side of the fridge and attach a PC case style fan and run it once a day for a few minutes, sucking the air out. but I have a few questions. 


Will this be enough air exchange?
Is airflow in the chamber while the fan is not running important? 
Do I need another vent to let fresh air in when running the fan?
What are other methods people use?
I want it to be as automated as possible so but also the best solution based on science. Sorry if this is a question asked a lot but I can't really find a good explanation on the parameters around how much air needs to be moved and what the reasons are. 

Thanks


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## indaswamp (Apr 19, 2020)

How many cu. ft. is the refrigerator you are using? Knowing this will help fine tune your set up. It is easier to control the humidity the in a larger space. 

And with most set ups using a standard upright frost free refrigerator, air exchange is not necessary if you are using a dehumidifier. The whole point of air exchange is to remove the humidity, which the dehumidifier will take care of. Also, if you live in a high humidity area like I do, where the RH inside your home is 45~60%, then air exchange is futile and will not solve the problem of high humidity inside the chamber because you will be pulling in humid air- not dry air. As the warm humid air cools, the humidity actually goes UP. This defeats the purpose of the air exchange.  

As far as air movement, there will be plenty enough during the cooling cycle when the refrigerator kicks on. In some cases, it could actually be too much air flow (regardless of humidity) which is why home made curing chambers can tend to have some mild case hardening compared with commercial  set ups. Also, the humidifier and dehumidifier will contribute to airflow while they are running.


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## indaswamp (Apr 19, 2020)

With regard to the Inkbird humidity controller...

It is best to use 2 inkbird humidity controllers so that you can control the humidity within a range, and not a set point (a cheaper option compared to the Auber and yet still have the ability to maintain a range). This will prevent the humidifier and dehumidifier from fighting each other continuously. Set the humidity controller on the low side, say 72~75% and allow for overshoot to stabilize around 80%. Set the dehumidifier controller to power on at say 86% RH, and shut off at like 83% RH. This will prevent the dehumidifier from overheating the top of the chamber walls (trying to push the humidity down to the 80% set point), which in doing so will prolong the cooling cycle (as the refrigerator tries to cool the walls/remove the heat) and that prolonged cooling cycle means that the fan is running longer, drying out the salami too much....

It is a very fine balance between humidity, temperature and air flow in a home made curing chamber.
Also, I installed a relay on the humidifier circuit. The humidifier will not power on while the refrigerator is running. This is to prevent the accumulation of condensation on the evaporator coil and walls. If allowed to accumulate, you will get a humidity spike immediately following the cooling cycle that your dehumidifier will have trouble handling...and it will be on for too long, heating the top of the chamber walls....the cycles will be too fast, and the fans will run too much, your salami will dry too fast........creating case hardening...


Anyways, hope this helps. Some of the things I have learned running my chamber.


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## indaswamp (Apr 19, 2020)

Also- you can calibrate your humidity controller with 2 parts salt, 1 part water (by weight-use an accurate scale) in a small container. Place this and the sensor in a ziplock bag overnight, The RH should read 75%, if not the note the offset.


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## Apophis13 (Apr 20, 2020)

Hi 

 indaswamp


Thanks for the quick reply. Very good info. will try without a fan 1st. I live in Melbourne Australia so the average RH is between 48 and67% . My fridge is 320 L (Metric for the win) wich is 11 cu. ft.

I will have a look at using two controllers for humidity once  I get started and get my head around the intricacies of my set up. 

Thanks for the help.


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