Temperature Control nightmares

[Mcdddy]

Hi - I have a hell of a time controlling temps on my KK. When opening the lid temps want to take off. I have been going back and forth using bellows with temp controller and then just using vents sometimes in the same cook. Using drip pan for heat deflector for my low and slow smokes. My GF smoker - so easy fill charcoal in chute ignite close up turn on fan control - watch rock solid temps +\-  a 1-2deg F as long as I want. I’m getting so frustrated spending so much effort to get even modest control. Below pretty good control until taking off ribs to wrap.

[Syzygies]

There's a classic book from the early days of aviation that all pilots read: Fate is the Hunter

The author was on a final flight before a long-awaited fishing vacation. The plane was making awful noises. He finally crawled into a wing cavity to explore, telling his copilot to do nothing. He then ignored the issue, and flew cautiously to a safe landing. There was a welcoming party. The other two planes of his type, same service history, had crashed while he was airborne. A long investigation concluded that the only way to avoid crashing was to do nothing. He took this as an omen, and retired.

I believe that you're oversteering. Perhaps you're also starting with too much fire; always light just enough charcoal to pass command to the temp controller.

See how close to sealed you can close the upper damper without putting your fire out. Partially close the valve on the bellows, if necessary. Wait twenty minutes between reactions.

I like to file things into psychological categories. Controlling a fire, like some but not all cooking tasks, gets better when one stops "caring so much".

I tend to place my controller temperature probe through the top lid hole that normally holds the analog thermometer, with an alligator clip (roach clip) as stop. This can read cold at first, and hot later, but I've had better luck controlling fires this way than with the standard advice to position the probe an inch away from the meat. It eventually doesn't matter; for low & slow the entire cooker converges on the same temperature, after this initial imbalance.

Edited September 15, 2023 by Syzygies
This is a family newspaper.

[tony b]

One of our "cardinal rules" here in KK land is "Don't chase the temperature." Folks think they have to keep making adjustments in their vents to hit a target temperature. One of the basics of BBQ is that a precise temperature is not required - there's no "magic" temperature for perfect BBQ. Rule of thumb is +/- 50F of what you're aiming for is "close enough for government work." 

I think @Syzygies was on to something about the size of your initial fire. You said, "When opening the lid temps want to take off." That's counterintuitive to my experience and the old BBQ saying of "If you're looking, you're not cooking." as opening the lid lets out heat. The short infusion of fresh air from opening the lid (unless you keep it open for a while) shouldn't cause a spike in your temperature. One check on this is to see how much charcoal you've burned through on a short cook, like ribs. If you've burned through most of the basket, you probably had too big a fire to start with. A chimney full of lit charcoal is way too much fire for a low & slow cook in a KK. 

Another variable is what charcoal are you using? You didn't say in your post. Most quality lump hardwood charcoal burns fairly slowly and evenly. Some of the cheaper stuff (i.e., Cowboy) which is made from scraps, burns up in a flash and very hot. Give Fogo or Jealous Devil a try. Many of us here on the Forum use those charcoals with good results. 

Keep us posted on your experiences and we'll see if we can get you on the right track. 

[C6Bill]

If you are using a controller make sure those bottom vents are closed and never touch them. When you go to wrap the ribs open the lid snd take the ribs out and immediately close the lid. Once wrapped open the lid and put them back in and close that lid. After I do that I always close my top vent about an 8th of a turn. Then walk away. Hope that helps

[David Chang]

i am a fireboard user and we have a lid detection setting where you can disable the fan when there is a sudden drop in temp (lid open)

i'm not sure if you can enable something like this in the billows app. if not, the fan may be overcompensating when you opened the lid as seen in the green spike. also what is your max fan speed set to? if max speed, it's going to be trouble..

also, are you using the yellow billows damper?

 

Edited September 17, 2023 by David Chang

[C6Bill]

Good point on the damper David

[5698k]

I can’t help but think there’s too much fire lit, and you’re choking the fire. I have no issues with opening my lid mid cook, with no temperature spikes.

I have my controller set up, light a small amount of coals and close the lid. I’ll open the top a full turn, and monitor the temperature increase. Once the temp is within 50° of my set point, I’ll set the top just off the seat. You want the fan to work to keep temp where you want it. I simply don’t have the issues you’re describing, so I can’t help but think that there’s a set up issue.


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[jonj]

This is the Billows damper setting I use:

Just barely open with the damper plate. Let the fan work on the intake and output sides both.

[Cheesehead_Griller]

I've had my KK for a bit over a year now. Temp control was something I stressed about when I began my journey. I was guilty of the whole "temp chasing" by making adjustments continuously. Using either just the vents or a temp controller, I learned one thing. Lesson learned is that the top vent only needs to be opened 1/8 of a turn to keep temps at or below 250F. I was opening it 1/4 or 1/2 and would experience temp runs like you have. Additionally, I no longer use Fogo XL or large charcoal like that. Basic Fogo is my go-to and I've had much more consistent temps. 

[Mcdddy]

Sorry everyone I just have so many questions. First off I have both a fireboard and flame boss temp controllers - in this cook I was using the flameboss. I use fogo premium and cocochar. First, For low and slow I need to use some sort of deflector so I can get indirect cooking - is it better to use the Kk drip pan ( I have double insulated) or I have heard some use aluminum foil over lower grate - one layer or how many layers? Doesnt the foil have a tendency to move around or float from the hot air rising? How do you keep it down in place? Also, I think I am using too much charcoal - Dennis had me thinking a full basket of charcoal for a 6 hour cook is perfectly fine. Rum & Cook says he uses basket splitter pretty much always esp for low and slow 1/4 basket rarely 1/2 basket. I haven’t been using my splitter and have been loading up the basket 1/2 to 3/4 full. How open on bottom vent if top is 1/8 turn for 225-235?

Wondering if I should just ditch the fan and just monitor grate temp with flameboss or fireboard. Then just learn vent settings?

Thanks for everyone’s input. 

 

 

 

[Mcdddy]

On 9/16/2023 at 10:03 AM, tony b said:

One of our "cardinal rules" here in KK land is "Don't chase the temperature." Folks think they have to keep making adjustments in their vents to hit a target temperature. One of the basics of BBQ is that a precise temperature is not required - there's no "magic" temperature for perfect BBQ. Rule of thumb is +/- 50F of what you're aiming for is "close enough for government work." 

I think @Syzygies was on to something about the size of your initial fire. You said, "When opening the lid temps want to take off." That's counterintuitive to my experience and the old BBQ saying of "If you're looking, you're not cooking." as opening the lid lets out heat. The short infusion of fresh air from opening the lid (unless you keep it open for a while) shouldn't cause a spike in your temperature. One check on this is to see how much charcoal you've burned through on a short cook, like ribs. If you've burned through most of the basket, you probably had too big a fire to start with. A chimney full of lit charcoal is way too much fire for a low & slow cook in a KK. 

Another variable is what charcoal are you using? You didn't say in your post. Most quality lump hardwood charcoal burns fairly slowly and evenly. Some of the cheaper stuff (i.e., Cowboy) which is made from scraps, burns up in a flash and very hot. Give Fogo or Jealous Devil a try. Many of us here on the Forum use those charcoals with good results. 

Keep us posted on your experiences and we'll see if we can get you on the right track. 

Consistent temps during the cook I have always considered tantamount to good BBQ and temp swings the enemy of good Q. Not sure what your referring to +\- 50 deg - are you referring to prior to putting the meat on being totally fine?  I’m not so concerned with aiming for 235 and hitting 250-260 or more before I put meat on and staying at that temp but I am concerned about not maintaining that temp throughout the cook.

Edited September 19, 2023 by Mcdddy

[Cheesehead_Griller]

7 hours ago, Mcdddy said:

Sorry everyone I just have so many questions. First off I have both a fireboard and flame boss temp controllers - in this cook I was using the flameboss. I use fogo premium and cocochar. First, For low and slow I need to use some sort of deflector so I can get indirect cooking - is it better to use the Kk drip pan ( I have double insulated) or I have heard some use aluminum foil over lower grate - one layer or how many layers? Doesnt the foil have a tendency to move around or float from the hot air rising? How do you keep it down in place? Also, I think I am using too much charcoal - Dennis had me thinking a full basket of charcoal for a 6 hour cook is perfectly fine. Rum & Cook says he uses basket splitter pretty much always esp for low and slow 1/4 basket rarely 1/2 basket. I haven’t been using my splitter and have been loading up the basket 1/2 to 3/4 full. How open on bottom vent if top is 1/8 turn for 225-235?

Wondering if I should just ditch the fan and just monitor grate temp with flameboss or fireboard. Then just learn vent settings?

Thanks for everyone’s input. 

 

 

 

For reference, I have a 32BB. I use either a sheet pan or foil as a heat deflector. Foil will not move on you. Note, if the meat is going to drop a lot you may want to put a pan on top of the foil to catch the drippings. For a six hour cook, I'd recommend using the basket splitter. For a long 12+ hour cook I'd recommend a full basket of lump. 1/4 or 1/2 for a short cook would be more than sufficient. Bottom vent should be open maybe the first notch or two. Not too much though to keep it at 225F. 

[jeffshoaf]

The references to too much charcoal are referring to how much charcoal you have burning, not how much you have in the basket. The kk's are so well insulated and efficient that you require very little burning to get to lose and slow temps. It's tempting to start a big fire and get to temp quickly but you really need to light just a few pieces of charcoal and bring the temp up slowly. Having a full basket is just insurance that you don't run out of charcoal mid-cook; it doesn't go to waste since you can easily kill the fire at the end of a cook by closing all the vents and then reuse it for your next cook. The basket splitter is useful for making it easy to switch the type of charcoal between cooks and to create direct and indirect cooking zones.

If you have too much charcoal burning, your temp controller is most likely smothering it to keep the temps down, so when you open the lid the sudden in-rush of air fuels all of that smothered charcoal and let's it flare up, causing the temperature spike - it's the back draft affect.

Regarding a deflector, if you only have a little charcoal burning, you rarely need a deflector in a kk; I only use one if I'm using a drip pan to catch drippings for aus jous or gravy.

[tony b]

@jeffshoaf makes some excellent points, as do the others in this post. 

My +/- 50F comment was about not fretting if you're cooking temperature is not exactly where you aimed. As noted, don't try and chase the temperature. You'll just get frustrated - and it really doesn't make a whole lot of difference in the final result. 

I 2nd the comment about the amount of charcoal in the basket - it's the amount of charcoal that gets lit, not how much total is in the basket. Snuff the leftovers for another cook. One of the benefits of the KK. 

I generally only use a single sheet of AL foil on the lower grate for an indirect cook. All you're trying to do is block the Infrared radiation of the fire from reaching the food. You only need to cover as much of the lower grate as the footprint of the food above to allow airflow. If you wrap the foil ends around the grate rods, you shouldn't have any issues with the foil moving about. 

Another thought about using any temperature controller & fan units - keep the damper on the fan output fairly closed (1/4 open). Make the fan do the work to push the air through the grill. Keep the top vent just barely open, open it just until you see smoke escaping. One of the things that can happen (a chance that this is what caused your spike) is that a good breeze blowing across the top vent can cause what's called "vacuum drag" and actually pull more air through the grill than the controller wants, leading to a "runaway." Once the grill temperature gets a few degrees above the controller's setpoint, the controller quits effectively working, as it can't lower the temperature back into the control band. You're at the mercy of Mother Nature at that point for the breeze to calm down and the fire to die back down so the controller can take over again once the temperature recovers to the setpoint. Keeping the top vent and fan dampers mostly closed will help prevent that runaway from happening. 

[C6Bill]

On 9/19/2023 at 1:34 AM, Mcdddy said:

1 First off I have both a fireboard and flame boss temp controllers - in this cook I was using the flameboss.  ......

2 How open on bottom vent if top is 1/8 turn for 225-235?

3 Wondering if I should just ditch the fan and just monitor grate temp with flameboss or fireboard. Then just learn vent settings?

Thanks for everyone’s input. 

 

 

 

1) I dont think Flameboss does a good job on the lid open detection, but there is a setting to lengthen the time the fan stays off buried in their menu. I'd stick with the fireboard, it seems to do a better job of that, but that is just my opinion. My main issue with flameboss was their probes. I really liked the product other than the probes. But i think fireboard is a better product. 

2) Just remember if you are using a controller close that bottom vent, if that is open at all while using a controller you will have trouble maintaining a consistent temp. I did it once just from force of habit, opened the bottom vent for 235 and then setup the controller and walked away, couldnt figure out why my temp wouldnt settle down until i went back and looked and saw what i had done lol

3) Ditch them both until you learn your vent control, do a short low and slow with ribs during the day so you can master the vents, they are really easy on the KK so you'll have a real good idea after one cook without a controller. I just took pics of the vent settings for future reference until i had it figured out.

[Mcdddy]

C6Bill I hunted all over flameboss app and couldn’t find lid detection settings to change.

[Mcdddy]

When are people starting their ATC’s ? After a desired temp reached with manual vent control or from very early on after coals lit and lid closed? 
I have had probs with the Lump I light catching lump around it on fire throughout the cook in the past and fire dipping and temps dropping. I thought maybe this was due to using less than a full basket and not using a basket splitter to force the charcoal to stay in contact especially vertically. If I’m using less than a full basket I should definitely use basket splitter?

[jonj]

I start mine without the temperature controller and wait until the KK is close to, but hasn't yet reached, target temperature. 

[jeffshoaf]

18 hours ago, Mcdddy said:

When are people starting their ATC’s ? After a desired temp reached with manual vent control or from very early on after coals lit and lid closed? ?

I usually start the controller as soon as I light the fire but I initially set the temperature 75-100°F lower than my actual target temperature and then step it up as the KK approaches the current set temperature. This helps keep the fan from blowing fill blast and getting too much charcoal burning during the preheat and/or overshooting my planned cook temp.

[tony b]

I have a Guru. I set it up to go right from the start, right after starting the fire. Let the controller & fan do its thing. Most overshoot problems come from windy days and getting vacuum drag across the top vent. Best way to prevent that is to have the top vent barely off its seat and to close the damper on the fan output to less than 50% closed. Since doing this, I've rarely had an overshoot problem on a long low & slow cook.