Relative Humidity in your Smoker - Meat Processing Equipment 303

Jonathon

Relative Humidity

Attend this advanced-level class from Meatgistics University by watching the video, reading the article and post any questions you have!

Relative humidity is a measurement of the amount of water vapor in the air at any given time in a specific environment. This is calculated in a few ways but we are going to do it in this article by the difference between a “Dry Bulb” and a “Wet Bulb”. Commercial smokehouses will often have something called a psychrometer that will measure and calculate this for us, but we assume you do not have one of these so we will show you how we did it it with the Smoker Soaker Towel

First, we took 2 Madgetech Wireless Thermometer Transmitters draped a Wet Sock over one of them, and placed that wet sock into a bowl of water to keep it moist through the smoke cycle. The other one we placed about 2 inches directly above the other one. This gave us a wet bulb/dry bulb reading that we could use to calculate the relative humidity using the Weather Prediction Centers calculator.

Why you should care about Relative Humidity

There are 3 main reasons that RH matters to you and your smoke schedule. 1st is that the higher the relative humidity is the less your smoker will fluctuate in temperature. 2nd is that a higher RH will stop your product from drying out during the cooking process. 3rd is the one we are most concerned with and that is that it will help prevent "the stall", where your product sits between 130 and 140°F for what seems like forever. It does this by making it harder for the moisture that your meat has pushed to the surface to evaporate off of the surface of your meat. This is similar to what your body does when it sweats, think about how much hotter it feels outside when the humidity is high, same basic thing here.

Walton's Smoker Soaker Humidity Towel

We recommend you get a large water pan and place it in your smoker on the bottom rack on top of a solid pan. Then wet your Smoker Soaker Towel and drape it over the edges of the pan, making sure that the center of the towel is down in the water. This will allow the wicking material of the towel to pull water up from the center of the water pan. The towel increases the surface area for evaporation and is made of material specifically designed to increase evaporation.

Results of Relative Humdiity Testing

We started with an RH of 12% with just the water pan. Then when we added our Smoker Soaker Towel and tested it 30 minutes later we got a reading of 39.5 (Dry Bulb 181 and Wet Bulb 142). 30 Minutes later we had an RH of 47% (Dry Bulb 174 and Wet Bulb143), and then we had another reading of 47% (Dry bulb 181 and Wet Bulb 149). So, we were able to increase the relative humidity by 400% with the Smoker Soaker Humidity Towel!

Full Chart

Feel free to look at the chart below to see the results of our smoke schedule!

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eschmid2

Hi !

First thanks for the video I really loved this and wow that’s a huge difference with the soaker towel to get to 40+% RH. I few questions:

Was the water preheated before adding it to the water pan? If so what temperature? Was it taken to boil point?
The information you gave is not sufficient to get the relative humidity … the calculator you referenced calls for entering temperature and dew point, your instructions say to use the calculator with wet bulb and dry bulb temperature readings. Dew point requires a calculator also, it requires wet bulb and dry bulb temperature. Most wet bulb dry bulb charts online only go up to about 130 F. Can you provide a link for a calculator you use for smoking with wet bulb an dry bulb capability to 212 F?
Can you point to any information how you could do such an experiment for smoking temperatures above 212 F such as 250 F? Everything changes after 212 F when it comes to humidity and I have been searching for a method to get RH at a smoking temperature of 250 F. I do not have access to expensive professional smoke house monitoring systems so this would be something for us small guys!

Thanks for your great educational video’s !!
Eric