Crashing temps on PBC again *sigh*

[New2Cue]

This morning I got the PBC going, and at the last minute figured that I'll monitor the temps. It was cranking along steadily at 275, threw the ribs on, and not even a half hour later my Maverick is yelling at me that the temps are below 220. After cracking the lid to get things re-established, I moved both racks to one of the rebars, and put the other rebar into only one of the holes leaving the other hole open. It's been at 270 for the last couple of hours and hasn't budged.

Not sure exactly what my issue is. I'm wondering if it's the high humidity here (I'm in the DC area and it's miserable). I did a long brisket cook a few weekends ago and the temps were steady the whole time. It's a bit frustrating.

I thought about modding the lid to add one of those Weber dampers (saw the mod on youtube). Cheap solution, but I just got a WSCGC which has an temperature control inlet built into the kettle. So, I'm considering just getting some kind of fan unit that maybe can work across both cookers.

Has anyone else added a Weber damper to the lid? I also posted this on the accessories board, but any recommendations for ATC devices that can work across both the PBC and the WSCGC?

Thanks in advance!

[N227GB]

I don't think ambient air humidity is the culprit. We have daily afternoon rain showers here on the gulf coast all summer long.

Are you following the lighting procedure stickied here in the forum?

[New2Cue]

Yep, I've tried it all different ways and still have issues after three years and probably 50+ cooks

[MBMorgan]

High temperature and humidity can both affect the PBC ... just like they affect aircraft performance. Basically, high temp means a given volume of air contains fewer air (and therefore oxygen) molecules than normal. High humidity means that the increased number of water vapor molecules will displace some of the air molecules that would normally be there.

I did a quick calculation for your area on a hot, humid day:

• Altitude: 100 ft above sea level (I guessed at this for your area)
• Temperature: 90 deg. F.
• Altimeter setting: 30.3 (that's what is is right now in DC)
• Dew point (related to humidity): 80 deg. F.

Under the above conditions, an airplane (or your PBC) will perform as though it's sitting at just over 2100 ft. msl.

At 2100 ft, I calculated that your lower vent should be about 1/2 open (roughly 50%) ... which would look a bit like this:



I'd suggest that you try this during hot, humid times of year and see if it helps.

[tdimond]

I might have to dust off my thermo skills.

Are you using standard temperature and pressure for the nominal amount of oxygen that is available? What relative humidity level?

Some of this also depends on the conditions when Noah calibrated the lower vent opening.

[MBMorgan]

tdimond - To be honest, there are some good density altitude calculators and this is one of my favorites: https://wahiduddin.net/calc/calc_da.htm

I've used it as a pilot a number of times and even though I'm a retired geophysicist, I didn't feel like reinventing this particular wheel. I'm sure that SL STP is the baseline condition but I don't know what the dev used for baseline relative humidity.

[MBMorgan]

tdimond - fortunately there is a good reference section that explains the math and underlying assumptions.

[Brewmaster]

I installed a https://www.amazon.com/LavaLock%C2%A...B28W0XH13YVQHQ helps keep the temps where you want them with large cooks

[New2Cue]

I saw those - they look interesting. Do you have to cut the triangles out? How easy is it?

Also, one concern I have about drilling into the PBC is whether it will rust in the exposed spots. Did you paint or otherwise refinish it?

Thanks again!

[JGo37]

Good mod - I would get a damper or chimney from a UDS supplier before using the Weber damper...

[Brewmaster]

It was easy to install and I did it 2 years ago, no rust at all, the smoke coming out has enough fat content that rust can't start

[jecucolo]

So I think you might just be running some fatty ribs. If MBMorgan ("science the sh@t out of it") solution doesn’t work just pick up a small twig from the yard and just prop one side of the lid. It really doesn’t take too much additional air to get the temp up.

[New2Cue]

That was another thing I was considering - that the fat drippings were extinguishing the coals. Would take a lot though, no?

[Thomassen]

My temps are going South, too, but not as far as yours. Starts at 350-375, drops to 270-290 for a couple of hours, then drops to 240-250. I'm basically at sea level.

[Polarbear777]

I went the other way and installed a fan controller. Whether I have the normal intake open or not, it certainly takes care of the problem.

Did 6 racks of ribs today and then corn then smoked cashews then set to 375 for "cleaning mode".

[New2Cue]

Looks steady - maybe a fan is just the best option.

[jecucolo]

Before you go spend a bunch of money go to the pit barrel forum. There is a sticky topics that give some very good help starting the pic. fzxdoc has put some real good instructions on lighting techniques. If in high altitude it is 15-10-10 low altitude it is 10-10-10. The nice thing when using these methods is the fire gets off to a roaring blaze which will usually get your temperature where you want it. @jerod used to load up his pbc with multiple briskets and high moisture was something he spoke about often. Starting the PBC really is the key to good temps.

[HawkerXP]

Agree!

[New2Cue]

I’ve used Noah’s method, the PBC forum’s method, etc. and run into that problem. I’m wondering if the lower vent needs to be opened more on hot, humid days.

[Jerod Broussard]

I've never had luck messing with the bottom much beyond what is recommended. The real help with temp comes from above as stated above. My thread for installation. All I have is a dremel and a drill.

https://pitmaster.amazingribs.com/forum/grills-and-smokers/charcoal/pit-barrel-cooker/184911-thinking-up-another-pbc-mod

[New2Cue]

Thanks Jerod - cool mods! Do you worry about the exposed steel rusting?

[Jerod Broussard]

I got so much rust on this thing (original powder coat) I ain't skeered. I'm really kinda waiting for the bottom to fall out.

[smn1285]

I’m in MD, so I assume our weather conditions are identical. I’m not having temp dipping issues with my PBC. I’m smoking 2 pork butts tonight and will let you know if anything goes wrong. But I’ve been successful with it holding steady around 270-280. I do all the normal lighting procedure stuff... fill the basket, 40 (yes I count) coals in the chimney. I let the chimney go 8 mins, then I dump the coals and let the PBC come up to temp, as opposed to staring high and going down. This has seemed to work for me in the last 1/2 dozen cooks or so.

[New2Cue]

I’ve done it that way too - just unsure what is going on. Yesterday I had a less full basket so maybe that was part of it.

[RobertC]

This morning I got the PBC going, and at the last minute figured that I'll monitor the temps. It was cranking along steadily at 275, threw the ribs on, and not even a half hour later my Maverick is yelling at me that the temps are below 220.

I feel your pain. PBCs have a bug (high latency and poor modulation) that has been turned into a feature ("Set it and forget it!"). I think you can expect that once you drop food into the cooker you'll lose a bit of heat; in addition, when the basket is less-than-full, you'll get a larger variation in temp as each briquette represents a larger fraction of the total fuel load. I would try a full basket load and "overshooting" the target temp by a little bit.

[New2Cue]

Thanks man. I'm doing an overnight brisket cook tonight. I individually stacked each briquet in the basket to maximize the coals in the basket. We'll see if that works a little better, as I want to be able to get some sleep tonight

[smn1285]

Individually stacked?!?! Sheesh, I hate counting 40 for the chimney.

[jecucolo]

There are a couple of other thing you might try. Change to Kingsford profession or B & B charcoal. They burn hotter. Also Spinaker has the OCD method of stacking the charcoal. See photo. It works good.

[New2Cue]

I did something like that tonight but arranged them in rows for the first level, then two rows flat on top. Not as pretty as Spinaker but the basket was pretty heavy.

[Spinaker]

Looks great to me!

[hogdog6]

I love you OCD guys 😜. I’m with smn1285 counting out 40 is more than I want to deal with.

[smn1285]

New2Cue how’s your cook goin? I put my 2 pork butts on about 30-40 mins ago. My PBC temp is holding around mid 240s so far.

[New2Cue]

Got a 10 lb brisket on at 11:30. Temps were slowly crawling up to 315 in the barrel but I had to redo hook placement because the brisket was scratching the top of the basket. By the time I re-hooked, temps jumped to 450. I closed the barrel, temps fell the 370 and have been around 330 ever since.

I give up - I can’t figure it out. I’m wondering if having a full basket helps stabilize temps?

[New2Cue]

I’ve gotten away with fewer briquettes on shorter cooks before, which makes me think that temps and humidity might play a factor.

Good luck with your butts!

[smn1285]

So I woke up around 5:30am and the PBC was at 190ish, butts at 167. It’s almost as if the drippings did extinguish one small section of coals. So I got a stick and moved the coals around, and I’m back up in the 230s. I also think I’m bad at evenly spreading the lit chimney from the start.

[Rfuilrez]

I use a temperature controller on my PBC. But, I don’t evenly spread the coals. I put most of the coals on the side of the basket opposite the air intake and only a small amount on the side with the air intake.

I also never count or pretty up anything. I just dump what looks to be a good amount into my chimney and get it going and then fill the basket.