smoking WSM: Controlling Fire Temp w/Exhaust Vent...Email from Harry Soo

[Roguejim]

This is according to Harry Soo. Contrary to just about everything I've heard about vent adjustments on a WSM, or any smoker for that matter. I hear Harry is rather familiar with WSMs.

  Should work on a kettle, no?

""Of the three components I mentioned: intake, fuel choice and amount, and the exhaust, the most effective component to maintain constant temperature is not the intake nor the fuel. It’s the exhaust. Many beginners I come across are not aware of that. All seasoned pitmasters know how to intuitively draft their pit using “clean” smoke to color and flavor their barbecue meats. The draft refers to the vacuum effect when you open or close the exhaust vent of your pit.
When you open the exhaust vent on the WSM, you allow hot air to leave the pit and this creates a vacuum suction to draw air in from the bottom intakes. Thus, by skillfully manipulating the top vent, you can control your WSM like a pro. Many beginners constantly fiddle with their intake dampers in hopes to maintain a constant temperature with less success than leaving the bottom vents untouched and fiddling with the top vent to control the draft within their WSM."
 
http://www.slapyodaddybbq.com/2014/03/fire-control-and-seasoning-a-new-weber-smokey-mountain-pit/

 

[Bumper]

I'd wait for the bbq heavyweights to find this and post, but I do most of my temp control on my weber kettle from the top vent and it seems to work, so seems right to me.  That said I mainly use it for grilling and roasts

 

[midwestchilehead]

It can be done, but I have never closed down the top vent on my WSM to control temperature. I get plenty of control with just the bottom vents. And doesn't Harry Soo always use Stokers to control his fire?
 
Now on the komado, that is a different story. You have to use both top and bottom vents to get to the right temperature.

 

[Jeff H]

I'd wait for the bbq heavyweights to find this and post,

 
Well, this certainly isn't me but I'll give my 2 cents anyway.
 
If it isn't broke, don't fix it. I have zero issues maintaining temp in the wsm using only the bottom vents. With the water pan full and burning using the minion method, it is actually pretty hard to screw up the temps. The smoker just naturally wants to stay at 225-250 with the bottom vents only about 1/3 open or less. There is no real fiddling. Just check once an hour or so and adjust as necessary.

 

[LUCKYDOG]

My smoker/grill is pretty drafty I leave the exhaust completely closed and regulate with the intake. Once I get to temp I slowly start closing the intake till I get the temp Im looking for to hold. I imagine that with a lot of the "closed" smokers with a door and latch and air tight smokers this would work. But I dont think the intake is wide open either. 

 

[tctenten]

 
Well, this certainly isn't me but I'll give my 2 cents anyway.
 
If it isn't broke, don't fix it. I have zero issues maintaining temp in the wsm using only the bottom vents. With the water pan full and burning using the minion method, it is actually pretty hard to screw up the temps. The smoker just naturally wants to stay at 225-250 with the bottom vents only about 1/3 open or less. There is no real fiddling. Just check once an hour or so and adjust as necessary.

 
 
Far from an expert as well....I think this is right on.   A couple of times when my temp has spiked on windy days, I have closed the top vent a little to bring the temp down quicker.

 

[Roguejim]

From Harry Soo, 8/13.
 
"When I run my Stoker, the top vent is full open.  All the bottom vents are closed except the vent used to mount the stoker.















When I don't run my Stoker, my WSM runs best with one bottom vent full open and top vent full open.  After 3-4 hours, I open the second bottom vent.  After 7 hours I open the third vent.  This assumes I don't refuel my WSM.
 
Just to clarify, my article is for a normally aspirated WSM.  That, is, my instructions are for those WITHOUT an automated blower system."















 
 
Isn't it true that Weber also recommends controlling temps on the WSM via the top vent?  Just sayin'. 

 

[Kikaida]

Soo is a pro to be sure, but I agree with Jeff H. These smokers are designed so well that its hard to screw things up. Temperatures just want to stay in the zone, especially with a full water pan. Plus I want the smoke to roll out freely, nothing worse than over-smoked, resin covered bitter meat. Stifling the smoke and having it roll around in the chamber longer...over the course of hours...seems counter productive.

 

[grantmichaels]

Well, I kind of agree, in that I set the lower vents to be mostly stopped-down, and control the temperature by varying the top vent.
 
I think it's a bit deceiving to say I control it with the top vent, though, because the constriction and real-life control is coming from limiting the bottom one.
 
So, I think it's a matter or semantics ...

 

[Jeff H]

Well, I kind of agree, in that I set the lower vents to be mostly stopped-down, and control the temperature by varying the top vent.
 
I think it's a bit deceiving to say I control it with the top vent, though, because the constriction and real-life control is coming from limiting the bottom one.
 
So, I think it's a matter or semantics ...

 
 
You bring up an interesting point but here is a twist that I just thought of. Maybe it matters, maybe not.
 
3 bottom vents and one top vent. If you are running more than one bottom vent fully open or all 3 of them 1/3 open, then there is some constriction going on anyway. How much is too much??? IDK?!?
 
On a 225 degree cook with a full water pan the bottom vents aren't open that much but on a 300 degree cook with the water pan dry, all 3 vents are pretty much fully open.