A demonstration of creosote Part 1

  • Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
SMF is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

crankybuzzard

Smoking Guru
Original poster
OTBS Member
SMF Premier Member
Jan 4, 2014
5,611
2,932
Montague County, TX
“I have a black sticky mass building up in my smoker”

“My meat has a bitter flavor on the outside”

“I love my ribs, but my lips tingle and get numb after eating them”

These are a few things that are mentioned here on the SMF when folks have a concern with what’s happening to their meats in the smoker, and the above are generally an indication of creosote build up.

The first question we tend to ask is; “Is your exhaust port wide open?” A lot of the time we’ll get the answer that it wasn’t wide open and the next cook comes out without issue.

For the last few weeks I’ve been contemplating some ways to show the difference between an open exhaust and a closed, or only partially open exhaust on a smoker. Below, you’ll see part one of this endeavor.

First off, what is creosote? Creosote is a tar like substance that is generated through pyrolysis of organic materials. Basically, the smoldering of wood, or pellets, in a low oxygen environment. This residue will adhere to most surfaces of your BBQ pit and your meat, or other food, products that are inside of the smoke chamber, and leave you with the look, taste, or sensation listed above. Oh, it’s also carcinogenic…

To keep all tests on the same playing field I made sure of the following items:

• The heating element was turned on and was running a constant 100°, controlled by a recently tested PID.

• The same size of jar was used on both tests

• The same number of ice cubes were used on both tests

• The same amount of pellets were used in each test by weight

To perform the test, I first started the heating element inside of my electric pit. Once it was up to 100°F I then placed the pre-lit A-MAZE-N tray, with apple pellets, into the pit at the normal location I place it, a ½ pint jar of ice water was placed on a rack at about the mid-point of the smoke chamber, which is the location I seem to use the most.



I then closed off the exhaust port on the top of the pit, and the timer was then set for 3 hours of smoke.


After 3 hours, I removed the jar of water with tongs and brought it into the house for observation. There was a noticeable color change to the water, the exterior of the jar was quite sticky, and the smoke smell wasn’t pleasant, it was quite acrid. Using a dropper, I tasted the water and found it to be extremely bitter tasting, bitter to the point that I had to take a shot of whiskey to rid my mouth of the taste!
laugh1.gif




I then reset the sample to the same specifications as above, but this time I opened the exhaust fully and obtained a new jar of ice water to sit in the smoke chamber for 3 hours.


The results of this jar were quite different after 3 hours in the smoke. The exterior of the jar wasn’t as sticky, the color of the water wasn’t as yellow as the first sample, and the smell, while still strong, wasn’t as acrid as the first test. The flavor of this water was a subtle hint of bitterness, but NOTHING like the first sample was. I still cleansed my tongue with a shot though!
yahoo.gif




As you can see, there is quite a difference between the 2 jars of water.


So, what are my findings thus far, with the exhaust port closed, creosote has the opportunity to heavily form and condensate onto items that are within the smoke chamber. With the exhaust port open, a lighter smoke is obtained that doesn’t have the same acrid smell and bitter flavors.

Conclusion for this test, leave your exhaust port open.

Why did I do this? I’m a geek at heart and love to experiment. More will be coming to show in greater detail how creosote forms and adheres to meats…
 
Great Test, Charlie! 
icon14.gif


Another 8 or 10 tests you wouldn't care if it was smoking at all. 
cheers.gif


Bear
 
icon14.gif
 

That shows cold meat....   Is it time for a jar that is up to smoker temperature ??
 
Last edited:
Very cool experiment.  This should be a sticky, in whichever section the mods feel it should go.  I am sitting here at lunch and about 5 minutes before I read this, one of my colleagues whose husband just bought a smoker was telling me that she doesn't like the smoky taste of the food he makes in it.  Probably because he is brand new to it and common sense tells people they need to keep the smoke in.  I will ask her if he keeps the top vent open or closed.  

I would also like to give you Points, for making the sacrifice of drinking whiskey in the name of science.  You make us all proud and your selflessness should be an example for all.  In fact if I wasn't at  work right now, I would have one in your honor haha

Great post!
 
Good example of the two extremes
icon14.gif
. I am not at all surprised that with no air flow through the smoker that it was not at all nice. As part 2 are you planning on repeating the test with the vent half open to see if it is closer to the fully open or fully closed result?
 
 
icon14.gif
 

That shows cold meat....   Is it time for a jar that is up to smoker temperature ??
YEP!  This test was for basically an almost cold, to warm, smoke scenario. 

The next test will be just that.  Same scenario, but at 225-250°, and I'll probably extend the smoke time to roughly 6 hours, kind of the "middle range" of time for the regular items we smoke (chicken, ribs, brisket, etc...)  Also, 2 (larger) jars per test will be utilized, one with ice water and the other with ~70° water to simulate cold meat vs. room temp meat going in.

I also have another test I'm writing up the plan for now, but I need to find a couple of mediums to use.
 
Last edited:
This is a good illustration of how over smoking cheese is accomplished.

If you had pulled the jar with the vent closed when it reached the same color as the one with the vent open, wouldn’t they have tasted the same? This is why I suggest smoking to a desired color rather than by time. The color that you smoke too will depend on your individual taste. In addition, by cleaning the smoke, you will find more smoke flavor without the creosote buildup.

Example: http://smokingfoodwithmrt.com/smoke-direct-vs-indirect

If you continue with your test, you will notice that the closer the smoke and jar temperatures are to one another, there will be fewer deposits accumulated on the jar.

Good job, point,

Tom
 
First of all THANK YOU for the a truly amazing, well-done test, and for taking the time to document it and post the result. This is really useful.

I'm still not entirely satisfied with my MES 30 Gen 1, specifically because of the smoke quality. I'm pretty sure that many things I did when I was a newbie fifteen months ago ended up creating creosote. I sure did get some tongue-numbing nuts, and believe me, you don't want your nuts to numb your tongue.

I switched to using the AMNPS, and that helped some, but I found that I still got bad smoke at low temperatures. Your test reveals some of what may be happening, although I always keep the vent wide open, and also added a mod in place of the chip loader which significantly increases the airflow through the smoker

I know there are threads about the importance of TBS, and other posts about improving the quality of the smoke. Some of these talk about the water pan (pretty clearly a bad idea to use in an MES); some talk about temperatures (the colder the smoking temperature, the more likely to have creosote problems); the venting (the subject of this thread); the source of the smoke; and more.

Of all of these, the mailbox mode seems like the most likely thing that would further reduce the bitterness. Do you have a mailbox mod and, if so, would you be willing to do one more test using that? I have been meaning to build some variant of the mailbox mod, in hopes that creosote would condense in the mailbox and/or the duct connecting the mailbox to the smoker, but since it requires an hour or two of work, I was looking for some additional, concrete reasons why it would be a good thing.

If you do the test, I'll pay for the whiskey.

[edit]P.S. I'm simultaneously following this thread:

Clean, Cool Smoke via Thermodynamics

That thread leads to this blog post:

Smoke Direct vs. Indirect

which begins to answer some of my questions about using an external smoke box.

These two threads together are providing all sorts of great ideas of how to get a better result.
 
Last edited:
 
The first question we tend to ask is; “Is your exhaust port wide open?” A lot of the time we’ll get the answer that it wasn’t wide open and the next cook comes out without issue.
The word "wide" is quite important here as many discussions revolve around the difference between the top vent being "Wide" open or "Partially" open. Having the top vent fully closed is obviously a problem (as you have shown) but is it necessary that it is "fully" open? The previous test with 1/4, 1/2 and 3/4 open would be helpful.
 
Last edited:
To me, this also signifies the importance of using dry pellets as well.  Leaving them in the hoppers of the pellet poopers outside for days on end can't be helpful, imho:  I'd think that they should be nuked before each burn to make sure that there's not any moisture (hello, humidity) that's been absorbed.
 
 
This is a good illustration of how over smoking cheese is accomplished.

If you had pulled the jar with the vent closed when it reached the same color as the one with the vent open, wouldn’t they have tasted the same? This is why I suggest smoking to a desired color rather than by time. The color that you smoke too will depend on your individual taste. In addition, by cleaning the smoke, you will find more smoke flavor without the creosote buildup.

Example: http://smokingfoodwithmrt.com/smoke-direct-vs-indirect

If you continue with your test, you will notice that the closer the smoke and jar temperatures are to one another, there will be fewer deposits accumulated on the jar.

Good job, point,

Tom
I agree with you Tom about how easy it is to over smoke cheese. I am not so sure about judging it totally by colour though as it will depend on the smoke. I usually find that with the thin smoke, if you can see colour it is already over smoked with some woods.

Yes, having the ice cold water in there will certainly magnify the effects of the tar in the smoke.
 
 
To me, this also signifies the importance of using dry pellets as well.  Leaving them in the hoppers of the pellet poopers outside for days on end can't be helpful, imho:  I'd think that they should be nuked before each burn to make sure that there's not any moisture (hello, humidity) that's been absorbed.
When preparing the pellets, the microwave is your best friend 
icon14.gif
 
 
The word "wide" is quite important here as many discussions revolve around the difference between the top vent being "Fully" open or "Partially" open. Having the top vent fully closed is obviously a problem (as you have shown) but is it necessary that it is "fully" open? The previous test with 1/4, 1/2 and 3/4 open would be helpful.
If I get enough interest in this little project of mine, I have quite a few different tests I would like to do, 1/4, 1/2, 3/4, etc is on the list as well.

I have an MES, but I chose not to use it since it's on a cart in the garage and quite difficult to get to.  However, after getting a couple of PMs, and seeing that a lot of the potential issues folks are having are with this type of smoker, I'll probably perform the remainder of the higher temp tests with the MES.  That will also show a definite position of the exhaust port since it has a pattern, so to speak.
 
 
I agree with you Tom about how easy it is to over smoke cheese. I am not so sure about judging it totally by colour though as it will depend on the smoke. I usually find that with the thin smoke, if you can see colour it is already over smoked with some woods.

Yes, having the ice cold water in there will certainly magnify the effects of the tar in the smoke.
That's another reason that I used the apple pellets, light colored and light smoke overall.

I have 20 pounds of mesquite pellets, that would make for a very different color and overall creosote experience.  But, always a but, I do plan to continue using my smoker and don't want to have to spend 8 hours burning it out and cleaning it up when this is all said and done.
 
SmokingMeatForums.com is reader supported and as an Amazon Associate, we may earn commissions from qualifying purchases.

Hot Threads

Clicky