Managing airflow in the WSM


 
K

KenB

TVWBB Fan
I just read a review on amazon for the WSM from Harry Soo. I always thought the intake vents were used to control the temps in the cooker but Harry states that the exhaust should be used. I was told that the exhaust vent should be fully open all the time while cooking or bitter taste in the meat would result. How many control temps from the exhaust vent?
 
I do, but only very rarely, when it gets impossibility hot. The key, I think, is to be sure the exhaust vent is open more than the input vents. That keeps the air moving through the cooker. I've never experienced the bitter taste. I would imagine that you really need to choke off the fire to end up with that result. Like much of what you read on forums, many things get repeated so many times, that they generally become accepted as true. I refer to that as the conventional wisdom. The conventional wisdom usually has some basis in fact, but that doesn't necessarily make it true in all cases.
 
I use the top vent routinely. As long as it's open more than the bottom three to maintain a chimney effect you don't get bitter stale smoke.
 
Seems odd to say that the exhaust vent or top vent needs to be open more than the input or bottom vents. There are three bottom vents and it would seem typical for those to be open more than the top vent. I realize that when you're running low and slow, it can be the case that with only one vent partially open (which is the way I run when shooting for about 275°), the top can be open more than the bottom, but at the start of the cook and in high heat cooks, the bottom vents (when taken as a whole) will most always be open more than the top. So basically, the top vent is generally the limiting factor in hitting higher temps. That's why if you crack the lid or even go as far as installing another top vent, you will hit much higher temps.

As for controlling temp with the top, I have generally kept the top vent open all the way and have had no problem hitting my target temp. There have been times when the fire got away from me and I did close the top vent for a short time. I noticed nothing different about the taste of my food. I think it's better not to, but for a short time, it worked and I tasted no ill affects.
 
Jerry N. said:
Seems odd to say that the exhaust vent or top vent needs to be open more than the input or bottom vents. There are three bottom vents and it would seem typical for those to be open more than the top vent.


I realize that when you're running low and slow, it can be the case that with only one vent partially open (which is the way I run when shooting for about 275°), the top can be open more than the bottom, but at the start of the cook and in high heat cooks, the bottom vents (when taken as a whole) will most always be open more than the top.
Click to expand...

Generally, my bottom vents are nearly closed, and the top vent is fully open (unless the temp gets out of control). Just my experience, but to me that seems like more exhust venting, than intake venting.
 
My take is a little different on this. Since I use a controller (HeaterMeter) on my WSM22, I have my top vent partially open and two of my bottom vents closed and the third bottom vent controlled by the controller with a tiny fan. When I look at the graphs of my cooks I see that the fan is on most of the time but mostly at very low speeds and I am able to maintain exceptionally stable pit temps. If anyone is interested, I could post a picture of the graph I just took that will illustrate this. The key is it does not take a lot of venting on a WSM to keep a good low and slow cook going. All night, my biggest spike was less than 10 degrees. I does not take a lot of air flow once you know your smoker.
 
I control temperatures with the bottom vents and keep the top vent fully open. However, if the WSM gets too hot with the bottom vents closed, then I partially close the top vent to reduce the heat. If there is not a lot of smoke coming out of the top vent, then I think it is OK to close it down.
 
Bob Ivey said:
My take is a little different on this. Since I use a controller (HeaterMeter) on my WSM22, I have my top vent partially open and two of my bottom vents closed and the third bottom vent controlled by the controller with a tiny fan. When I look at the graphs of my cooks I see that the fan is on most of the time but mostly at very low speeds and I am able to maintain exceptionally stable pit temps. If anyone is interested, I could post a picture of the graph I just took that will illustrate this. The key is it does not take a lot of venting on a WSM to keep a good low and slow cook going. All night, my biggest spike was less than 10 degrees. I does not take a lot of air flow once you know your smoker.
Click to expand...

And I believe Mr Soo uses an ATC also, so your post offers a good explanation.
Before Weber added a lid therm most of us used a therm that stuck into one of the vent holes by using an old wine cork or silicone plug. We basically shut that vent down by a third and I don't recall or experienced any foul tasting smokes.

Tim
 
Interesting. I will try Harry Soos method this week of controlling temps with the top vent and only using one bottom vent. I will also try no water. I have been using the top vent open and using water and burning through a ton of charcoal.
 
If I remember right, Weber recommends as a starting point top vent wide open and bottom vents open half way. Then control temp by closing down the bottoms gradually.
There are 3 on the bottom so sometimes easy to forget to keep that chimney flow going with just 1 on the lid. There more than just 1 way to control the heat. Whatever works
best for you after experimenting.....
 
KenB said:
... using water and burning through a ton of charcoal.
Click to expand...
There's a hint in there, somewhere...

As you mentioned, going the no water route may help you, if you also start with less lit coals.
 
Last edited:
You must log in or register to reply here.

 

Back
Top