Smoker temp drop question

[Swamp_moss]

Hello again all. I’ll try to keep this brief and to the point.

I’m aware there are tons of threads on the Akorn about temperature control but I am struggling to find the answer to a specific question. If someone could link me to a thread already about this that would be awesome.

Put my butt on this morning at 281. Smoker recovered to 270 in 20 minutes. From there it has slowly dropped all the way to 225 as of 5 minutes ago. I don’t feel this is a normal fluctuation for my cooker. My question is, can the water evaporating out of the butt (8lb from Harris Teeter) cool the pit temp 40 degrees over the course of 5 hours? It is really steaming out there now (no water pan, just a pan to catch grease and the diffuser).

I don’t understand why I cannot make it settle in at a temp this go round. It’s never been super easy for me but I can usually get it to ride in a 10 degree span for most of a 10 hour cook without too much adjustment

 

[fivetricks]

Hmm. Seems like a fuel or air issue.

Not sure where you live or what your weather is like today, but high winds and colder than normal.outside temperatures will also have that effect.

 

[Swamp_moss]

Hmm. Seems like a fuel or air issue.

Not sure where you live or what your weather is like today, but high winds and colder than normal.outside temperatures will also have that effect.

Thanks for helping me brainstorm. Temps are mild, 47 when I started ~60 now. Was very rainy this morning but little to no wind.

Left a very big open area in the center of my coals and had two small fires going. Easiest run I’ve had getting up to/maintint temps to begin with and all about sunrise things tanked. They stabilized back around 253 and when I got back from lunch they were at 225. No adjustment whatsoever. Finally I went out and really cranked the throttle to get it back up to 275 and now I’m finally humming along. I really want to believe in the “get the temp set, add meat and leave it alone” strategy but that has not worked for me today.

Can water evaporating out of the butt cause this much of a lowered temp? Thanks again

 

[mike243]

Don't know if it can but rain falling on it will drop the temp quickly as it sucks the heat right out of it.

 

[Swamp_moss]

I should’ve mentioned it is under a tent. This thing blows my mind. It kept climbing to 290, I barely (guys I can’t emphasize how small of an adjustment I made to the top vent) closed it and now she’s dropping like a rock.

Don’t get me wrong I’m not expecting anyone to fix my problem, but it is incredibly frustrating. Even when it “settles” it isn’t settled.

 

[noboundaries]

To answer your question, no, water evaporating out of the butt will not cause a 40F chamber temp drop. A cold butt, straight from the fridge can absolutely cause a temp drop as the meat absorbs available heat. That's what is known as a heat sink.

Let's assume you stabilized the chamber temp at 275F before you added the meat. That means your heat triangle of fuel-heat-air is in a state of 275F equilibrium. If you never added the meat, it would burn at 275F until the fuel was exhausted or the heat was reduced by insulating ash.

But, you added cold meat to the smoker. Understand, you stoked the fire triangle with excess air when you opened the smoker to add the meat. It is now burning hotter than 275F due to the excess air.

You close the lid and reset the balance of 275F for fuel-heat-air assuming you do nothing to your vents. But, the overstoked fire appears to make the smoker recover part (or all) of your chamber temp.

The meat starts absorbing heat. The chamber temp drops. Your fire is still burning at a 275F balance, but the meat, closer to the thermometer, is absorbing heat away from the fire. If you did nothing, over time the chamber temp would rise as the meat temp rises.

By resetting your vents to "crank the throttle," you are now burning hotter than 275F. The chamber temp will rise beyond 275F as the meat temp rises. You can end up chasing temps for the entire smoke as the meat temp rises. Now you're trying to choke a fire to get temps back where you want them.

So, if you followed all that, the bottom line is get your fire stabilized at your desired chamber temp. Add the meat and leave everything alone when the chamber temp drops because it will rise again as the meat temp rises.

 

[Swamp_moss]

To answer your question, no, water evaporating out of the butt will not cause a 40F chamber temp drop. A cold butt, straight from the fridge can absolutely cause a temp drop as the meat absorbs available heat. That's what is known as a heat sink.

Let's assume you stabilized the chamber temp at 275F before you added the meat. That means your heat triangle of fuel-heat-air is in a state of 275F equilibrium. If you never added the meat, it would burn at 275F until the fuel was exhausted or the heat was reduced by insulating ash.

But, you added cold meat to the smoker. Understand, you stoked the fire triangle with excess air when you opened the smoker to add the meat. It is now burning hotter than 275F due to the excess air.

You close the lid and reset the balance of 275F for fuel-heat-air assuming you do nothing to your vents. But, the overstocked fire appears to make the smoker recover part (or all) of your chamber temp.

The meat starts absorbing heat. The chamber temp drops. Your fire is still burning at a 275F balance, but the meat, closer to the thermometer, is absorbing heat away from the fire. If you did nothing, over time the chamber temp would rise as the meat temp rises.

By resetting your vents to "crank the throttle," you are now burning hotter than 275F. The chamber temp will rise beyond 275F as the meat temp rises. You can end up chasing temps for the entire smoke as the meat temp rises. Now you're trying to choke a fire to get temps back where you want them.

So, if you followed all that, the bottom line is get your fire stabilized at your desired chamber temp. Add the meat and leave everything alone when the chamber temp drops because it will rise again as the meat temp rises.

Thanks for the help NB. Only thing is I didn’t chase at all until the temps fell below 220. A slight adjustment open, 30 minutes later no change. Rinse repeat again. That’s when I had to adjust more aggressively. There is no middle ground today. I’ve pulled the butt at 202 IT and plan to let the grill sit at the current vent settings until I go to bed to see IF it will settle out

Again I appreciate the help

 

[mike243]

I would leave the top wide open and try to adjust the heat with the bottom vents just saying

 

[forktender]

Adjust the heat by adding or taking away in coming air flow and fuel, not by closing the out going damper/ smoke stack. The only reason the damper is there is to snuff the fire and keep the rain and critters out of your smoker, its not there for temperature control. Let the meat temp and chamber temp settle in and always add a handful of coals, wood or whatever fuel you're using when you add the meat. And open the air inlet or fire box door for a few minutes until the temp starts to rise then back it down to where you normally run your smoker, maybe just a touch more open until the meat and smoke box temps stabilize.