Smokin-It pushing smoke out?

[toejam]

Got a quick question. I'm smoking a store-bought, pre-cooked, smoked ham. Yeah, it's already supposed to be smoked, why am i re-smoking it - there is no smoky flavor in store-bought hams! Anyway, I put the ham in the smoker, Smokin-it #3.5d, and noticed I had to change the controller settings. It was set for:
stage 1
Smoker temp - 225
Cook until - time
Cook time - 2.00
Stage 2
Smoker temp - 225
Cook until - time
Cook time - 2.00
... all the other stages were the same ...
I needed to change stage 1 duration from "time" to "food temp" "145 deg"
As I was changing the settings for stage 1, the smoker (which had already started and had started kicking out smoke) started to shoot smoke out the vent. That smoke came out like there was a fan pushing it out - which we know there is no fan in the Smokin-It # 3.5D. The burst lasted 1-2 sec and then was done.
So, I'm curious as to why I got a burst of smoke shooting out of the smoker as I changed the settings.

 

[JLeonard]

Unsure about your question....
But, I love a double smoked ham!

Jim

 

[Inscrutable]

Interesting. Never saw anything like that in my #3 Analog. Seems awfully brief to have been from a brief temp spike.

You might post in the SI forum

 

[old sarge]

It might have been a silent belch since it was of short duration. Relax and enjoy!

 

[Dave in AZ]

Expansion of air. Initially air was ambient temp as you messed with controls. As wood heats up, it releases methane. At some point there, you got above ignition temp for the wood and methane. Small bit of methane ignites, increases temp of air inside smoker.

Suddenly the volume of smoker air increases a bunch as it goes from 80f or whatever your ambient was to 150 or such after quick burn, pushing resulting smoke out hole. Pressure equalizes and temp drops, smoke stops coming out.

The smokin It is susceptible to a quick flash burn due to how airtight it is, you can build up a good bit of methane before a coal ignites it. A lot of times when folks first open door around 5 min or so, oxygen rushes in, makes spark, and there is a big flash bang.

I have the 3.5D also. I used to make charcoal and also methane by heating sawdust without air... it's quite dangerous in volume. Will scare you first time you get the fire flare in the smokin it. Several threads here and on smokin it forums on this. Nothing to worry about, but I am careful first time I open door around 5 min. I also use an external smoke generator that blows smoke in, as well as a suction fan on top, so don't get this anymore.

 

[toejam]

Expansion of air. Initially air was ambient temp as you messed with controls. As wood heats up, it releases methane. At some point there, you got above ignition temp for the wood and methane. Small bit of methane ignites, increases temp of air inside smoker.

Suddenly the volume of smoker air increases a bunch as it goes from 80f or whatever your ambient was to 150 or such after quick burn, pushing resulting smoke out hole. Pressure equalizes and temp drops, smoke stops coming out.

The smokin It is susceptible to a quick flash burn due to how airtight it is, you can build up a good bit of methane before a coal ignites it. A lot of times when folks first open door around 5 min or so, oxygen rushes in, makes spark, and there is a big flash bang.

I have the 3.5D also. I used to make charcoal and also methane by heating sawdust without air... it's quite dangerous in volume. Will scare you first time you get the fire flare in the smokin it. Several threads here and on smokin it forums on this. Nothing to worry about, but I am careful first time I open door around 5 min. I also use an external smoke generator that blows smoke in, as well as a suction fan on top, so don't get this anymore.

Wow! That sounds very plausible. It actually happened twice and the smoke shot out of the vent so fast it made a whooshing sound.

Ok, if it is methane ignition a few questions pop up:
- how do we prevent/minimize this?
- are there flames in the wood box, or in the cooking chamber? If in the cooking chamber, is this flashing the food that's being cooked? Do I have to worry about the entire load of meat being cooked getting charred?
- if you use a suction fan, how does that impact the smoke generation? Right on the top of my head I'd figure you'd be burning through your wood a lot faster.

I've got my work cut out for me, gonna scour the forum archives for comments on this methane ignition/explosion.

 

[toejam]

Ok, I detected a trend on some of these conversations - this is ocuring with pellets, which is what I was using (trying to get rid of old inventory). If this occurs mostly with pellets, i'll just dump the old pellets and only use wood blocks.

Still scouring through the forum comments about this flash burn/methane explosion topic.

 

[DougE]

Pellet grills can go boom for similar reasons. If you have a flame out and try doing a relight without clearing the pot (provided yours doesn't have a startup bypass like Camp Chef) you end up with way too many pellets in the firepot since the controller starts feeding more pellets in like a normal startup. The result is excess gases while the ignitor is trying to light the overloaded pot. Once ignition finally happens, the excess gases ignite with spectacular results. I know your's isn't a pellet grill, but the principle is similar.

 

[Dave in AZ]

Happens with any wood. Usually only an issue until the first glowing coal appears, after that any methane produced just burns off as it is made. Doesnt produce much heat, it is the exact same as turning on propane grill and not lighting it for 20 or 30 seconds.

You don't need a fan on top, I do that when I want to dry stuff out like snacksticks. The smokin It or Cook Shack are so tight that moisture doesnt leave otherwise, it's like a sealed oven.

You don't have to worry about burning meat or anything. Just know that a flammable gas builds up as wood is heated, and until the first coal, it's gathering in your smoker. If you whip open the door at the right time, a gust of air and O2 can make that 1st coal, and you get a flash. Or it happens on its own without much fanfare if you leave door closed.

Also, if you use alternate smoke methods like actually lighting some on fire, like Amazn things, or the Bella smoke generator, then this never happens. Only if you toss wood onto a mild heat source like electric element and let it gradually heat up until it reaches ignition temp.

 

[dr k]

Wood gas igniting with too many chips or pellets. Can blow the chip loader out the side of Masterbuilt smokers, blow smoke rings out the top vent and can chug like a train.

 

[toejam]

Thanks for the feedback. Sounds like I should not have an issue with this, just be aware that it can happen.