Can Humidity Cause Creosote?
 

Sometimes my butts collect creosote, and it's not from using green wood. Saturday night, it was pouring rain and the air was 100% humid when I started the cook. The next morning there was dense fog and the air was still 100% humid. I noticed an off color in the smoke all night - almost whitish/yellow. I could smell creosote in the air. Sure enough, I tasted it in the Q on Sunday. I am beginning to suspect that 100% humidity is causing creosote. Thoughts?


I was cooking 4 butts with "barn seasoned" hickory, cherry and apple (dry as a bone) on a 1995 Pitts & Spitts UTSB3060. I packed and lit 10 or so logs initially at midnight, then reloaded with 4 more at 8 am. The cooker ran at 210 most of the night.

It is not so much the humidity as it is the barometric (air) pressure.

A smoker with borderline draft will draft less at low pressure (rainy day), than it will a high pressure (sunny day).
Draft is the flow of air through the smoke chamber, so less flow of air means you have a bigger potential for creosote formation on the meat.

People that use green wood to smoke with typicallly have a very hot fire with a strong draft to avoid this effect.

I'd say your main problem is that you put a bunch of logs in the firebox and let the fire smolder for a long time thus producing a lot of slow/stale smoke which over-smoked the pork butts. If you would've used charcoal i doubt you would've had this problem but you almost treated this cook as i would my woodstove and damp it down to give a long burn time. Although i get my stove very hot before i damp it down so that's it's hot enough to get a good draft going. I also agree completely with Sirporkalot that air flow was a major part of your problem.

When use my stick burner i go through a fair amount of wood because i don't want a smoldering fire, i want a good clean burning fire and it is more difficult to accomplish that on a rainy/damp day. But i'd never just pile a bunch of wood in there and let the fire "creep" along, even on a beautiful day. I also think that 210° might be part of the issue since the smoker it's very hot therefore effecting the daft, then you add in the humidity factor and if the smoker was out in the weather the rain was cooling it off even more. My suggestion is to ramp the temps up to 250° and build small/hot fires. Takes more tending but you don't end up with bad tasting butts.

I'm not familiar with your particular cooker, but I am familiar with the manufacturer. What stands out to me is that you loaded up 10 logs at first? Unless they were small splits that's a pretty big load of fuel, and if it all lit early in the cook I'm having a hard time understanding how it cooked at 210* and burned clean for that period of time, no matter what the humidity was.

Did I misunderstand your initial post?

Sounds like an unclean fire. Perhaps too much wood in the smoke chamber to get enough air between your wood to burn clean.

Creosote is just steam and unburned carbon based products, to minimize creosote your exhaust needs to be 100% open at all times. Always make sure your exhaust outlet is bigger than your intake outlet.

Thanks for all of the feedback Guys, I really appreciate it.

My draft is good. It looks like a locomotive right from the start. I must admit that I do pack the firebox full for overnight cooks. I light the bottom center area behind the damper with the loglighter, and wait several hours for the temps to regulate, dialing the damper back until it holds at 210 (BTW - 210 on the gauges usually means 225 in the middle of the cooking area). It tends to burn from the center outward through the night and not everything at once. In the morning, the outter logs still have their shape with a deep bed of coals in the middle. I was going to say that this is how I've been doing it for the 7 years I've owned it, but now I am wondering if I have been doing smaller batches of wood more frequently on daytime cooks. My problem my be occuring during overnight cooking only.....hmmm.

My chimney has a 6" flue - much bigger than the intake. It does have a cap, which can collect condensation that drips down on the upright part of the cooker.

For the next job, I think I will remove the cap, put less wood initially, and allow ample airspace between the sticks.

Thanks again everyone. Very helpful, as always.

Richard

Here is a link to a unit like mine: http://www.pittsandspitts.com/UTSB3060.htm

Have you ever tried dialing in at 250 on the gauge and maybe getting 225 @ cooking area, just kinda thinking you might burn more efficiently with a little hotter fire. Just a thought:)

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great question and a good answer!