Problem with Pork Butt temp swings on WSM 22” and CyberQ

[MattyP-MA]

I’m getting better and better with every smoke, but I haven’t done a Boston Butt in a year. It’s a 9.25lb butt that I started this morning with the CyberQ fan maintaining a temperature of 250*. I filled the water pan 3/4 full with like warm water. Everything was going nicely at 250* for the first 3.5 hours and then the temps started spiking to 280 or more. The water in the pan was a rapid boil, so I cooled it down with more water but that just ended boiling.

The only thing I could come up with is using a 2x4 to keep the lid up and provide cooling. The swings seems to stay between 250-275*, but sometimes go above or below briefly depending on the wind or lack there of. The dampers are closed at the bottom except for the fan port and the top damper I’ve messed with a bit. When it was working fine this morning the top vent was open about a pencils width.

I also noticed that the 3/4 full bag of Weber coals seems to have burned quicker than I remember. The charcoal ring was filled with briquettes and 4 pieces of apple chunks. The outdoor air temp is 45* in here MA.

Any suggestions for next time. Thank you.

 

[Fred BW]

I'm kind of thinking maybe you opened the lid and didn't give it enough time for the fire to die down some.
When the water started getting low,I'm sure that helped the temp to rise. You opened it up to add water,and air fueled the fire.
It can easily take a 1/2 hour or more for the fire to snuff back down where your temp control can kick in.
Putting a 2X4 in the lid to cool it down gives the opposite effect. It gives the fire more oxygen. Lighting more charcoal.
In my opinion 275 is not a problem,and the temp i try to cook most things. Swings up to 300 are nothing to get alarmed about.
Might try closing the top vent a little more,and be patient.
If you can't get the temp down with the bottom vents closed after 1/2 hour to 45 minutes you about have to have an air leak somewhere.

 

[MattyP-MA]

I only opened the smoker when the fan’s high temp alarm sounded. At that point the bottom vent was closed and the only top vent was cracked to a pencil width. That was a consistent temp for 3.25 hours using the minion method. It was only when the alarm sounded that I went looking to remedy the problem. I smoke everything at 250 to allow for the increase temp should it swing, but this was 275-300+ untill I found the right height to keep the dome open.

I think I need to use the some gasket kits to tighten up the door and lid top, bc there are obvious leaks.

 

[Fred BW]

I only opened the smoker when the fan’s high temp alarm sounded. At that point the bottom vent was closed and the only top vent was cracked to a pencil width. That was a consistent temp for 3.25 hours using the minion method. It was only when the alarm sounded that I went looking to remedy the problem. I smoke everything at 250 to allow for the increase temp should it swing, but this was 275-300+ untill I found the right height to keep the dome open.

I think I need to use the some gasket kits to tighten up the door and lid top, bc there are obvious leaks.

Yea,leaks would be my bet. I would probably also try Kingsford blue bag. I myself only use Weber charcoal when i want extra heat and longer cooks. Don't get me wrong. I don't think weber charcoal is the problem. I just think it's kind of expensive for every day use.
But with your vents the way they were the fire should have been on the verge of going out. It would be on my 18 anyway.

 

[MattyP-MA]

To your point, the full ring of charcoal did die down, but I’m not sure at what point in the cook. It may have been around 110* internal and that may have been around 1.5-2 hours from completion. When I realized it was dwindling, I started to throw some handle fulls into the basket. Maybe 30 briquettes. The 9.25 butt took 9 hrs to reach a 97* internal temp..

Fortunately, I purchased a bunch of Weber briquette bags last year when HD was selling them for $4 a bag. I’ll give King blue a try.