Is starting temperature and general burn stability key?


 
J

JohnA

New member
I have been using my own temperature controller (hardware and software) and have had mixed results. Although I have not settled on PID values optimal for my setup, it is not clear to me yet that those settings on their own determine results. I say this because after a few runs it seems as though at start of "cook" (in quotes because there is no food in the grill) the PID controller doesn't seem to ever really stabilize in a way that makes using the controller worth it.

However, after things get going for a while (including me initially manually controlling the baffle) it really seems to get rock solid after the initial start. Is this to be expected? For sure even with the overhead of the manual start it is worth it due to the generally long cook times. Once things get going I can keep temperature within a few degrees of the set point.

Is this typical? Or should I expect the PID controller to handle even the initial start as well?
 
I think the problem you might be having is if youre talking about putting the food on (Food acts as a heat sink, and lid off equals lost heat) your blower tries to play catch up because it thinks it is falling behind. Many people have had issues with this since a lot of the pellet grills came out with them, and the same issue has popped up for those who install them on kettles or bullet smokers. It can just take a bit of time for things to settle in as long as the door stays closed.

(T-ROY on Youtube talks about removing his blower until the pit comes up to temp so it doesnt start a runaway burn)

It may just be that you have to fine tune your setup on start up because variables such as humidity and temperature can affect how our grills/smokers handle airflow and thus efficiently burn fuel. You already have noticed once things are dialed in it is pretty much rock solid for you. A slightly less possible occurrence is that your thermostat in the grill(If a pellet) may be bad. That can cause an inability to maintain temperature, but I dont think that is the issue you are having due to how steady you say it holds after the initial setup.


If you are worried about fluctuation affecting your cook right as you are starting, I would not worry about that. You arent talking about leaving a roast on at 400 degrees when you intended to start it at 275, and leaving it for two hours until it is extra crispy. If it is as solid as you say, it may just be the personality of your grill and its own operating quirks.
 
Kudos on your homemade controller! I have a couple commercial units--used them some early-on--then abandoned them for no real logical reason. Keep in mind I'm only as sharp as a marble as I say this but after a few trial-and-error runs I kept the controllers off until the pit temp approached my targets and then I turned them on. In my feeble mind if I turned them on during the initial startup they had an "oh my God" period and took matters into their own hands, which wreaked havoc.
 
As you figured out it's a complicated dynamic .

But what you do not want is that blower on high, igniting new coals, which puts white Acrid smoke on your food

This is a problem at the beginning and even later in the cook. As best solved by starting with enough coals and having enough coals burning..... And not letting them go out. A controller will let them go out to bring the temperature down, and then blast them with air to get them burning again to get the temperature back up.

If you start without enough coals that blower will go on high for an hour trying to bring that temperature up to your set point

Smooth even temperature and air is what you need. Pretty much what happens naturally
 
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