DIY Smoker that controls humidity?

Jim_McCollum_69553

I built a home smoker already and it works alright, made plenty of great food.  I am planning on building a new model, and wanted to make one that could more precisely control humidity.  Some humidity sensor/controllers online (e.g., http://www.auberins.com/index.php?main_page=product_info&cPath=37&products_id=263) look like they'd do the trick, but they don't operate at high temperatures.  This isn't a critical problem, as often I smoke and cook food in separate steps, but it would be nice to find a humidity sensor/controller that operated at 225F.

Any ideas, comments on this idea, etc. welcome.  Thanks!

Chris_Young_80640

Humidity control in smokers tends to be very tricky. Nearly all humidity sensors that I am aware of (and I've looked at a lot) don't do well at high-temperature or humidity above 95%. Certain very specialized humidity sensors (chilled mirror dew point style) can do higher temperatures and humidity, but the smoke in the air quickly fouls the mirror, rendering it useless. 

Combi-oven manufacturers understand all of this, and they all do some very exotic things to try to control humidity accurately. Indeed, the patents on how a particular brand of combi-oven measures humidity tends to be one of the most valuable assets of these companies. Rational, for example, measures a very small pressure differential behind the spinning fan (this is the reason you only get two speeds, slow or fast, on the combi oven fan for a Rational) to measure the humidity. 

Anyway, I digress, the easiest thing to do is to create something like a simple wet-bulb thermometer to measure humidity (this is how $100k+ commercial smokers tend to do it). It's not perfect, and it's probably only going to be accurate to +-5%, but that's usually good enough.