Curious Observations on my 18.5


New member
I've been running a number of dry burns on my WSM 18.5 while I attempt to tweak my new ATC. Basically I load up the fire box and add 3/4 chimney of KBB. I'm running these test at 225* and 325* with the top vent fully open. Performance has been very good with respect to temperature regulation and prompt adjustments to temperature changes in cook temp. The system is working quite well and maintains the temp for hours as expected.

Part of this study was to observe any ash activity. I did this by incorporating my new stainless water bowl (thanks Chris) which is very clean and very shiney. Any ash produced floats on the water's surface and is easy to see particularly since no meat is involved.

Some ash has been observed but it does not appear to be any more significant than what a non-ATC WSM produces. However, this is not what got my attention.

At the end of these dry cooks, the water in the bowl is very dark brown, not something one would see in a standard black bowl. This isn't ash. I assume it is creosote which had condensed in the water. This doesn't bother me since I never utilize the water bowl for anything other than moisture production. But others do make gravies in this bowl by collecting drippings from the cook. This cannot be a good thing for those who consume this.

This may be common knowledge out there, I don't know but it's definitely something one should consider.
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TVWBB Wizard
Yeah it's fine to make an assumption but with all due respect that's all it is unless you've proven-out a given thought. While I didn't make it in my water bowl I made smoked ice on purpose last week. But I also never use drippings from the water bowl for gravy; if I want to collect drippings I use a separate pan :)


Well, I hate to break it to y’all, but smoke is composed of fine particulate from the combustion process. I worked in the clean room industry for many years, and a class 1 clean room can filter airborne contaminants down to 1 micron in size. Smoke particles are about half that size - versus a human hair which is about 60 microns.

Particles from wood smoke are between 1/2 micron and 1 micron, so yes, that brown stuff you see in your water is smoke (particles). And we find it especially delicious on our meats!

Creosote is a blackish brown oily substance and tends to come from poorly burning or incompletely burned fires (poor combustion).