WSM 18 running away


 
PeterD

PeterD

TVWBB Super Fan
I've got a disaster in the making for my brisket cook tonight and I have zero clue what happened or what to do about it. I've had wild temp swings on this thing in the past but tonight it's completely out of control. I have a Flame Boss controller, I lit about a dozen coals and put them on top of a heaping ring of unlit as I've been doing since 2008. Tonight the temps stabilized briefly and then shot off to the moon. I've got both bottom vents closed, the blower fan unplugged, the top vent open only about 10% but thick white smoke is coming out the rim in waves.

I opened it up to put some water in the water pan...and the damned water pan flipped over and spilled onto the coals and evaporated instantly. I righted the pan, put in more cold water, put the lid back on (again, top vend just open a little) and it shot right back up. I haven't done anything differently than in the past but something is obviously very, very wrong inside here.

I've got a 12# Prime brisket on the top grate and I'm afraid the thick white smoke is going to ruin it, not to mention cook it 10 hours before service at these nuclear-like temps. HELP!

WSM.jpg
 
The only thing I can think of is that you have a gap between the centre section and the lower bowl, or the door, unlikely as that is.
Or the flame boss went mental, and ignited more coals than usual, which set the wood alight as opposed to it smouldering. (Hence the billowing white smoke).
Did you find out what the problem was Peter?
 
Looks like the wood chunks caught fire. They were buried under a layer of unlit coals so it shouldn't have happened. When they went they also set my entire charcoal bed going full tilt as if I was grilling. There was almost no source of oxygen in the fire pit and the top vent was just open about 1/4 of the way. I don't get why this happened.

I typically have that happen deep into an overnight smoke. I follow Harry Soo's method of putting 4 or 5 chunks in first then covering them over with unlit, but I also add 1 or 2 more chunks higher up so that when these go they impart their smoky flavour into the meat at an earlier time. The decision to go out and buy a new pellet smoker is getting easier with each cook.
 
The last brisket I did was using the Soo method with an almost full layer of whiskey barrel stave chunks on the bottom. Filled the ring to overflowing, sidewinder ignition, went to bed. It was Kismet! Since I’ve never used any kind of ATC system I can’t speak to the wild issues that some folks seem to have. I added a few shovels of charcoal about 06:00 it was one of the easiest I’ve ever done. Wrapped and toweled about 13:00 and sliced around 16:00 and it was amazing! I will repeat this cook using the bourbon/merlot chunks I got from Fruita wood for my birthday! August 26 if anyone wants to send me a beef day card!
 
PeterD said:
........There was almost no source of oxygen in the fire pit and the top vent was just open about 1/4 of the way. I don't get why this happened.....
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Having the top vent open will still create a chimney effect, and the smoker will suck in air from any little nook & cranny it can find, even through the closed lower vents, as they are not fully air-tight.
 
TonyUK said:
Having the top vent open will still create a chimney effect, and the smoker will suck in air from any little nook & cranny it can find, even through the closed lower vents, as they are not fully air-tight.
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I was hesitant to close the top vent completely at the time. Whatever combustion was going on was dirty enough as evidenced by the thick white smoke, but I was afraid this would make it even worse.
 
Stability has been...ahem...problematic, but the cook seems to be proceeding. It's wrapped in butcher paper with waygu beef tallow at the moment, 195°F and climbing. I had to refuel after I got up this morning, then I wrapped at 9:50am. It's been in there now for exactly two hours.

What I did notice is that the bark has a very weird taste undertone, and I think this is the acrid combustion smoke having taken its toll early on. It felt like there was some fine particulate or something in the little bit I tasted when I wrapped. I'm guessing it has another hour or two to go, then I plan to let it rest at room temp until the internal drops from ~206° to 180°, then I'll re-wrap it in fresh butcher paper (with more beef tallow), and it will sit towel-wrapped in a cooler for at least three hours. We usually serve it between 4:30 and 5:30pm.

Here's the tale of the tape thus far:

wsm1.png
 
Jeff Boudman said:
Sounds like things are looking up.
What rub did you use?
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Just posted a separate thread about this in fact. I had lost my original recipe from about 10 years ago in a hard drive crash in 2019, and I forgot the proportions of everything. For this brisket cook I used a tablespoon of Morton's Kosher Salt, a tablespoon of black pepper (I think it's finer than 16 mesh, but not powdery-fine either), a half tablespoon of ancho chile, a 1/4 teaspoon of cayenne, and a teaspoon of coffee. I have serious reactions to onion and garlic so those are a no-no.
 
OK, so the followup from yesterday. I continued to have temp control issues, and for whatever reason any coals placed in the pit ignited fully and quickly. I gave up on finishing the brisket in the smoker. Once wrapped into the oven it went. And I burned the everliving hell out of my right hand taking it out. Suffering for my art and all that.

I got it up to about 203 or 204 internal and the Thermapen went in like buttah. I let it rest a bit at room temperature but not as long as I'd have preferred. With the 1st (thankfully) degree burns on my hand and a party that we were already an hour late for I cut short the initial rest at about 190, re-wrapped in fresh butcher paper and beef tallow, sat it in the cooler surrounded by towels for 3.5 hours. Tylenol #3s for the win; I was a hurtin' puppy lemme tell you. Severe lack of sleep plus a cooking anomaly was a recipe for disaster.

The point went over with residual cooking but nobody cared. It vanished. I set a timer...from first slice until crumbs was 4.5 minutes. The flat was the best I've ever done in terms of tenderness. Drape test and pull tests were perfect. Not much of a smoke ring, but I'd attribute that to the temp spike and the meat going from 35 degrees to 120 in almost no time flat. Bark was perfect as well. Wasn't thrilled with the rub, and definitely not as peppery as usual.


2021-07-03 14.05.58.jpg20210703_181805.jpg20210703_181652.jpg
 
It was amazing. The mouthfeel from the Wagyu tallow really makes a difference. I didn't think it would, but holy heck, it does. Hand is better, thankfully (tip of each finger got it, and the pad of my thumb got the worst of it). Still popped some regular tylenol to take the edge off.
 
Peter, was your lid seated properly? I had a similar issue once - piece of gunk/grease had formed in that area and it kept the lid from sealing. Huge temperature spike and the vents did nothing to control it. That 1/8 inch opening let enough oxygen in that temps ran wildly. Cleaned that up and no issues since.

Good to hear your cook turned out well!
 
Tye R. said:
Peter, was your lid seated properly? I had a similar issue once - piece of gunk/grease had formed in that area and it kept the lid from sealing. Huge temperature spike and the vents did nothing to control it. That 1/8 inch opening let enough oxygen in that temps ran wildly. Cleaned that up and no issues since.
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That was the first think I checked, but it's also where all the smoke was billowing out. When the WSM is running cold I make sure to prop the lid open a bit and the temps come up, so when they were spiking like mad that's what I looked at first, along with ensuring the two vents at the bottom were closed fully.

I had just cleaned the firebox out with Zep grill cleaner a couple of weeks previously and at the time I also scoured off all the creosote/etc.
 
I've got a disaster in the making for my brisket cook tonight and I have zero clue what happened or what to do about it. I've had wild temp swings on this thing in the past but tonight it's completely out of control. I have a Flame Boss controller, I lit about a dozen coals and put them on top of a heaping ring of unlit as I've been doing since 2008. Tonight the temps stabilized briefly and then shot off to the moon. I've got both bottom vents closed, the blower fan unplugged, the top vent open only about 10% but thick white smoke is coming out the rim in waves.
PeterD said:
I opened it up to put some water in the water pan...and the damned water pan flipped over and spilled onto the coals and evaporated instantly. I righted the pan, put in more cold water, put the lid back on (again, top vend just open a little) and it shot right back up. I haven't done anything differently than in the past but something is obviously very, very wrong inside here.

I've got a 12# Prime brisket on the top grate and I'm afraid the thick white smoke is going to ruin it, not to mention cook it 10 hours before service at these nuclear-like temps. HELP!

View attachment 31791
Click to expand...
Are you running your WSM "stock" or with door and lid gaskets? I know lots of folks say they aren't needed/necessary but I think they are helpful in preventing air leaks/temperature control issues. Lava lock i the brand that comes to mind. I also prefer the Cajun Bandit door over the stock weber door. Looks like the ATC actually overshot set point and then couldn't recover - this could be an air leak issue, or some chance that the ATC fan is too big for the cooker.

Looks like flame boss advertises a 21 or 41 CFM fans with variable speed - I wonder want the minimum cfm is for the fan, if it's 10% of max that's still a lot of air for an 18" WSM in terms of "air changes" in the cooker. The 18" WSM's interior space is probably < 4 cubic feet, so if the fan is blowing at 2 scfm it would replace all the air in the cooker in < 2 minutes which is probably too much air flow to maintain low temps.
 
The Flame Boss's fan control is very granular and in dozens of past cooks it's always been absolutely spot on. One change from this cook was I put on a few lit on top of the unlit and then spent the next 20 minutes trimming the brisket. Usually I put it on the pit a minute or two after dumping the lit on the unlit pile. I guess the ATC just put a bit too much air into the smoke wood and it lit off uncontrollably.

I have a Cajun Bandit door but no aftermarket seals. I think this will have been the last smoke on my WSM. I am now strongly in the market for a pellet smoker. I need a simple easy to use smoker and lately the WSM has just been a damned headache to use, to clean up and play with food on vertical racks.
 
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