Temperature Control with 18.5 inch WSM

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Original poster
Jan 8, 2014
Ralston, Nebraska
I've had numerous issues trying to keep a low temperature on my 18.5 inch WSM. The temp would hold where I want then would start to go up or down. I'd adjust the vents to try and bring it back to where I want it to be. It's be awhile since I have done a smoke due to family medical issues, but my WSM is still fairly new as I have done about 6 smokes with it.

The temperatures have seemed to run hot because what I thought would take several hours to do was done in much less time. Do I need to adjust all vents or just maybe 1 or 2 to maintain the proper temperature. I've also posted some questions with the TVWBB previously. Any assistance is very appreciated.

For the first dozen smokes or so a WSM may run hot and a bit erratically. The coating of soot and or grease needs to build up on the inside and seal little leaks and cut down on reflected heat. Give it a few more smokes and it'll fall in line.

Welcome aboard!
Basic set up and temp controll for WSM's:
  • Fill ring either 1/2 full for all the way full with unlit charcoal. 1/2 ring for smokes of 8 hrs. or less full ring for longer smokes. You can bury a few fist sized chunks of wood in the charcoal as well if you wish.
  • Light 1/2 a chimney of charcoal and let it get FULLY lit, then dump it in the middle of your unlit charcoal. I use big tongs to shift it into a little pile if needed.
  • Wait 5 minutes, assemble the smoker with all vents 100% open and no water in the pan.
  • Wait for the lid therm to come up to 200°, fill the water pan with HOT water, put the lid back on and wait for it to come back up to 200°. This is where I like to add 3 or 4 fist sized chunks of wood, lets them get up to temp and past the billowy smoke stage before adding the meat.
  • At 2nd 200° mark fully close two of the bottom dampers, let the temps come up to about 10° bellow your target temp, then adjust the 3rd damper to 50%-75% closed. Wait 10 minutes, watching temp guage carfully, if it is climbing to fast close the vent another 10%-20%, repeat as needed.
  • When you are steady at your target temp put the meat on close it up. Check therm after 10 minutes and adjust that 3rd vent if needed. You should be able to cruise at a given temp with little to no input from you for the entire smoke.
  • Side note - DON'T PEEK! When you lift the lid to spritz, mop, peek, tweak, whatever, it dumps your temps, but it also stokes your fuel by giving it a big input of air. This can lead to rollercoaster temps.
Now since your WSM is new it will burn hotter for the first dozen smokes or so. So you will need to damp it down sooner and may even have to close the 3rd vent entirely, the top vent will always stay 100% open. Once you get it running at a steady temp. make note of your vent positions and you will be able to dial it in much faster on your next smoke.
How low a temperature are you targeting?  I've never had problems with 225* in my 18.5" model. 

The next question would be have you verified the accuracy of the thermometer being used?
Hi all- I just got my 18" wsm last week. I have done 4 smokes on it so far(2 practice
/break ins and 2 food smokes). I am also have a bit of difficulty dialling in a good solid temp for a steady amount of time.

Rodriguez- I have done the minion method twice like to have described it. Do you find with only leaving one bottom vent open that the charcoal only burns on the side with the open vent?
I've been trying to maintain a 225 deg temp. The smoker would seem to increase and decrease depending how I set the lower vents. I have a Maverick ET-732 and have checked temp also using a Thermoworks Thermapen. I have only performed a half dozen smokes so far. I suspect from other responses that I need to do many more to get the build up on the inside of the smoker to help get my desired temp. I will trying using primarily 1 vent to control the temp. Any other suggestions are greatly appreciated.

Thanks for the various suggestions Johnny. I will try these out. I guess I'm a little inpatient thinking after a few smokes that my WSM would be ready to go. I do understand that it is going to require more. The temps did not seem to hold very long. Is it best to leave two of the bottom vents closed and leave the other one partially open? Thanks again for your suggestions.
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