Fire's Out!

[PeterD]

Hey all,

Had something "unique" happen to me earlier today. I put between 45 and 50 pounds of meat (3 butts and an überbrisket) on my 18" WSM. The charcoal ring was full to overflowing with CompK and a Minion start done with a handful of briquettes. Temps were set on the Stoker to 250 and I went to bed in full confidence that Meat-a-palooza was well on track. Weather conditions were low-70s with 94% humidity. Ick.

My wife wakes me up at 8 telling me the pit temp has dropped to 150. A quick check through the door revealed nothing but white ash. The food was quickly transferred over to a 250 degree oven and I did a full cold restart and the cook continued 90 minutes later. Although the catastrophe was averted nicely I'm left wondering why I used a full ring of fuel in less than 8 hours. Temps held rock-steady at 250 then fell off gradually. There was no spike, nothing. I've gotten 16 hours or more out of a ring that full of CompK in the past. Any idea what went wrong here? Was it the heavy meat load? Bayou-like humidity? Both? I'm trying to understand the physics of this thing.

Many thanks in advance.

 

[Bob Bass]

Most likely just the large meat load. As meat load increases, so does the fuel usage.

Also, in past tests, wasn't it found that comp k burns faster than blue k ? (just a thought...)
Although those tests were not controlled test (w/ a stoker or equiv.), I wonder what your results would have been with blue k.

Bob

 

[K Kruger]

How much lit did you use to start?

 

[JRPfeff]

Most likely just the large meat load. As meat load increases, so does the fuel usage.

Bob

I doubt that meat load can affect combustion. Combustion in solely contingent on fuel, flame and oxygen supply. The meat could slow the rate of warming of the WSM, but not the combustion of the charcoal.

I think this is related to the high humidity and the charcoal absorbing excess moisture from the air.

jrp

 

[Bob Bass]

Remember - he is running a Stoker !

The Stoker will try to maintain the setpoint temperature with additional combustion air and hence more fuel.

One item he might want to look at is where the Pit Probe was located.

 

[PeterD]

I used about 15 lit (give or take a few) and my pit probe was 1.5" off the grate, about an inch or so beside the point. The charcoal ring was heaped up and there were about 8 chunks of hardwood in there.

There were only two factors different in this smoke from others. Usually I'm doing one brisket, two butts or a couple of racks of ribs. This time both grates were chock full, and the brisket was draped over three foil-wrapped bricks. The second is I rarely cook when it's that hideously humid and sticky. A typical overnighter will be a lot less humid but about the same temperature.

I could see that the different formula of CompK vs Blue K might be a valid factor, but I've gotten 16+ hours out of CompK in the past. In fact, I get 14-15 hours out of it on almost every overnighter. The smoker was lit just after 11pm and started to cool off from 250 at 6am, steadily decreasing to fully out at 7:45am. Some other factor definitely affected the burn temp. I was under the impression that the meat load wouldn't really affect anything as it was just going along for the ride, as it were. The fire was going and maintained at 250--the meat just happened to be there in the same space.

 

[Jerry N.]

My guess is that the temp wasn't correct and the Stoker tried to compensate for that by running th efan and burning the fuel. Assuming your thermometer is accurate, I'd guess the combination of how much meat you had and the probe's proximity to the meat generated a bad reading and the Stoker kept churning to get the preceived temp up. I'm thinking it would be hard to tell due to the fact that there was so much meat on there, but did it finish early - indicating that the actual temp was rather high?

 

[Gary S]

Your meat would act as a heat sink too. With the temp set to 250 the Stoker would be calling for heat and the fan would stay on. Once your smoker reached temp the fan would stop but with that much uncooked meat the smoker would lose heat, start to cool down and the cycle would repeat but each time the fan would be running excessively and burning more fuel. I think it was nothing more than the meat load.

 

[Bob Bass]

Peter,

I relocated my pit probe after seeing where a noted championship pitmaster located his pit probe. Instead of just passing the pit probe into the wsm through a commercially available temperature probe grommet, the probe's silicone heat shrink tubing now rests inside the grommet with the tip fully exposed to the heat coming up from down below. We keep a clear path so that the probe is measuring the rising heat as it is applied to the 'smoking chamber'. Only downside is the probe now sees every minor heat source temperature fluctuation without first being somewhat dampened by the meat load.

hth

Bob

 

[PeterD]

I think I'm tending to go along with Gary's explanation. That makes the most sense to me, although the humidity is also a question mark. I rarely cook (or do much of anything else outside) when it's that goopy so I have no experience one way or the other. I only know that when it's a 90% humidity night my cigars don't smoke well and go out frequently and that's what made me think that the wet air may have played a part. But yeah, the heat-sink of 45 pounds of meat that went it at 35 degrees probably put too much of a drain on the available fuel supply. This will be the last time I'm doing that much at one time. For next year's party I'll do the pr0k the day before and just have the one brisket going the day-of.

 

[Dave Russell]

Comp K wasn't the issue. Too much meat in too small a space with probe too close to all that meat. Stoker simply ran fan too much in order to try to raise temp and burnt up all the fuel.

 

[Gary S]

This will be the last time I'm doing that much at one time. For next year's party I'll do the pr0k the day before and just have the one brisket going the day-of.

I would not be afraid of doing that much meat again, I would simply adjust my approach to the cook. I would not use an ATC at least not in the beginning. I would load the smoker as you did but let it come up to temp on it's own. All vents open. I would not be using a water pan for sure. I'm thinking foil the empty pan or a clay saucer. With that much meat you should be able to maintain a pretty stable temp but you would have to be prepared for a long cook.

I have read as much material as I could find on the WSM mods and I can say from my own experience adding a second dome vent sure makes a big difference in the performance of the 18.5 WSM. It's able to come up to temp much faster and can achieve HH very easily. You could easily reduce your cook time by changing the air flow from 3 to 1 to 3 to 2. Once you are at temp you are still going to have the "Meat Sink" issue to deal with but it won't be to the extreme and you can begin to shut down the second vent as the internal temp of the meat increases. It's all a matter of balance.

 

[PeterD]

For the once-a-year that we do meat-a-palooza it doesn't make sense for me to mod the smoker or anything else of that nature. Usually it's just me and my wife. Occasionally we'll have a third person over. I only ever foil when doing ribs, which I do without the ATC. My big cooks are all overnighters and I prefer to have the benefit of a controller and the peace of mind it brings to be perfectly honest. Since I put as much fuel in the ring as was possible, and it burned down to nothing that fast, I think just doing two cooks would be ideal. It also means less work for me to do at the party--the wife can handle reheating the pork and setting up the chafing dishes while I'm concentrating on the brisket cook.