Heat loss mid cook - how long does it take to recover?


 
I've been smoking on my WSM for about three years now and ran into an issue this past weekend that has me at a bit of a loss.

I was smoking a fairly large rack of spareribs. Temp was locked in at 225*. I use an iq120 ATC and recently re-calibrated my probes so I'm confident of my temperature readings. The ambient outside temp was about 80 degrees and dead calm (which is strange for Wyoming).

The WSM was cruising along for about three hours and as best I can tell never moved above 230* or below 225*. Unfortunately, after about that third hour a large thunderstorm rolled through. You don't get much advance notice on some of this high mountain storms so before I could get everything covered up the rain started dumping and we got wind gusts above 40mph. The outside temp with the storm also dropped into the low 60's. The storm lasted about 15-20 mins, and once it was done my internal temp in the WSM was down to 172*. It probably took me another half hour of stirring coals, etc. to get my temp back to the 225* range.

The end result was that it took me much, much longer to cook these ribs than I would have expected - even with the loss of an hour or so to the storm and then the recovery. I ended up pulling them after a little over 5 hours simply because we had to eat but they were nowhere close to ready. Cooked through, certainly, but not done in the sense we all know ribs should be. I estimate they could have stayed on the smoker another two hours to get them where I wanted them.

So here is my question after all that long-winded context: If you have a dramatic heat loss mid-cook, should it take that same amount of time to recover and be back on track, or is it almost exponential in the sense that losing a half-hour of time at your target temp actually means you'll probably need an hour, or two hours or more, in additional time to catch back up?

Put another way, if your product in the WSM is gradually increasing in temperature as it cooks at your target temp, but then starts falling in temperature due to external forces, how much longer does it take to re-attain that gradual increase in temperature? My guess after this weekend's cook is that if you lose a half hour in the middle, you'll need to add much more than that on the back end.

Curious for any thoughts from some of the experienced hands on here. Thanks.
 
From my own experience, I've had heat loss (because I didn't use enough fuel :mad: ) . I added more briq's and within 20 minutes (maybe a bit more but I've never made that mistake again) it was back to normal.

I'm wondering if rain got in and because you hadn't cleaned out the ashes from previous smokes ???? that the ash turned to sludge and blocked the bottom vents, thereby preventing proper air flow from bottom to top. Rain will roll off the top of the dome straight into the smoker, not down the outside. It's got nowhere else to go seeing as the lid sits inside the middle barrel. Need a roof over the WSM (either a table umbrella--without the table or a solid wood shelter) to keep 100% of the rain off the WSM).

Just a guess here. Keep that in mind.

edit-->the outside temperature drop would have little to no effect on your inability to raise the temp. People smoke at 30 below so cold is not really a factor.

You also lose heat when you take the lid off as you suggested, the time is about 25-30 min increase in cook time every time you take the lid off. That's why I rarely spritz anything while it's cooking. Too much heat is lost for little (IMO) benefit.
 
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Several thoughts - actually theories: if water seeped into the bottom bowl, it could have acted as a heat sink both from the mass of the water, but more so for the energy/heat that is required to cause the water to evaporate.

The other could be the charcoal was damp - even though the coals were burning, they may have been burning with less intensity, or cooler, from being damp.
 
Because the center section of the WSM fits inside the fire dome down below, it takes on a considerable amount of water when it gets rained on. That certainly could be part of your problem, Joe. You also lost 50 degrees of pit temp in a short period of time and had a fairly long recovery. Your ribs likely cooled down a bit and it took some BTUs to turn that around and get it going in the right direction again. You could be fairly accurate in estimating that you might have to double the "down time" to figure when your meat would be done.

This happened to me a couple of times during overnight cooks, where the weather dropped while I was blowing zs and I lost temp in the pit. You're right -- it's always a long climb back. I don't usually wrap, but on these occasions that's what I did to get back on track. You might consider some judicious wrapping if that happens again.

One more tip. If you keep your WSM outside (even with the Weber cover), try turning the center section upside down when you store it. It fits the top and bottom fine and the rain runs right off without getting inside.
 
I've got a very old and delapidated deck table with an umbrella that goes through it. I've had to drag it over to get the umbrella over the smoker. I've got the gaskets and it seems to keep the water from going in but it can still get in through the vent. But that wind is pretty killer on temp too.
 

 

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