Exhaust Control

I've always ran the stack wide open and controlled heat with the intake. same as you that's what I've always heard

I think it depends on your smoker, the “newer” Texas style pits are meant to run wide open where as some of the older designs would take advantage of closing the stack. Also, the comp style pits like Jambo also use the stack opening to control temps, they are designed for the stack to run a certain percentage closed (or open)

On my Shirley Paul recommends running the stack wide open but some owners report better smoke taste if they close the stack down claiming that the pit design is so efficient that you don’t get enough smoke taste. The new Goldie’s pit is designed to close the stack a certain percentage to increase smoke flavor as well, they went as far as engraving the underside of the stack vent so you can see what the percentage is. Again, each pit is a little different.

I've always run my Lang with the exhaught and intake wide open. I control the temperature by the size of the fire. I don't sweat the load over non substantial temperure variations.

I run my Workhorse 1975 with the stack damper closed 2/3 or 1/2 depending on the cook. It really depends on how fast your pit drafts. Do a biscuit test with the stack wide open and if your hot spot is in the middle, you can close your stack damper down to slow the airflow when needed and move that hot spot far to the right. When I went on a Texas bbq tour, a lot of the 1,000 gallon pits had the stack damper closed 1/2 to 3/4 since those pits drafted so fast.

Open

SkaterSmoker said:

I run my Workhorse 1975 with the stack damper closed 2/3 or 1/2 depending on the cook. It really depends on how fast your pit drafts. Do a biscuit test with the stack wide open and if your hot spot is in the middle, you can close your stack damper down to slow the airflow when needed and move that hot spot far to the right. When I went on a Texas bbq tour, a lot of the 1,000 gallon pits had the stack damper closed 1/2 to 3/4 since those pits drafted so fast.

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And to follow up, I don't close my stack damper to adjust temps. I use my fire size for that. Creating a the perfect draft is my goal when using the stack damper. I want my hot spot far to the right, which indicates enough airflow to remove moisture from the cook for rendering, and it's slow enough to add good smoke flavor. Look at the Franklin backyard pit, Franklin built it to draft perfectly as the default setting - the hot spot is far to the right dictated by the firebox size and firebox vent openings in combo with the stack height and diameter. For my 1975, I have to do some adjustments to get similar results.

This is an interesting topic. I am new to offset cooking but have always heard that you never want to starve the fire of oxygen or run the risk of dirty smoke. I kind of thought that you could starve it on either end whether you close down the FB or the stack damper. I may be wrong but if there is less going out, there can't be as much coming in.

But the thing that never occurred to me is how closing down the stack a little could affect the flow in the cook chamber differently than if you adjusted down the FB damper. It would be my guess that both could affect the airflow and hot spot locations, but maybe do it differently and to more or less of a degree of impact. Good topic.

agreed, it's an interesting bit of the process and a pretty good topic of discussion. I guess one of the things I dont really pay attention to is how much draft I'm getting or how much I should be getting. I wish someone had a good write up on this aspect (i suspect someone has at some point). surely there are some calculations that can be performed to figure out stack height/diameter, damper opening percent, etc just like there are for the design of the firebox and opening size into the cook chamber.

my ok joe is a bitch to keep consistent, it's constant tweaking of the intake damper and temp swings are huge (in my opinion), I try to run around 250-275 thru most cooks, but it's always swinging between 215-325, up and down, it causes me to make tweaks like every 10-15 mins if I want to stay remotely consistent. I really only have a problem when I get caught up doing other things around the house and lose track of time and I check the remote monitor and temps are up/down. if I get a break and chill for a bit I have the remote right next to me and I can keep the temp consistent but the cooker itself requires a fair amount of work to stay where I want it. it's actually one of the reasons I'm looking to get a bigger/better pit, everything I read tells me bigger pits are easier to keep consistent temps on and I'm sure some of that is the thermal mass of the cook chamber itself but surely some of that is the design of the draft/firebox/damper/stack relationships.

good topic

I'm not an expert on airflow or anything like that, but I can go by my experience and others with a similar pit as my 1975. When I first got my pit I ran it with the stack wide open, which had a very fast draft with the hot spot almost in the middle. What myself and several other 1975 owners noticed is that the food would come out with barely any smoke flavor, cooking times were very fast, and personally I noted my briskets were a little dry and crispy. Since using the stack damper and slowing the airflow and moving the hot spot to the right, my briskets have an incredible smoke flavor. They're not as dry or crispy either. I recently heard a top 50 pitmaster say the slower airflow keeps more humidity/moisture in the cook chamber creating a more tender brisket. I think each pit is different, so I think it's necessary to do testing with several different biscuit tests with different airflow settings, and then testing smoke flavor on short cooks. I cooked several 3" inch rib eyes with different airflow settings to gauge smoke flavor, because an oversmoked steak is very noticeable.

Here's an YouTube video I did on damper settings during a brisket cooking explaining the airflow and hot spot. Ignore the dirty smoke thing, I burn a clean fire in every damper setting, it's the slower airflow that gives the smoke flavor:

https://youtu.be/QClqddVHYNc?si=-7KGnyZX8UpWkEde

I, too, use the size of the fire (amount of fuel) to control temps. Both intake and exhaust wide open to provide for a clean burn and light blue smoke.

I guess another question as well. baffle plates. how much to they interfere with the draft? can they be used effectively to 'tune' where your hot spot hits? it sounds like something that might be worthwhile on a poorly designed smoker

SkaterSmoker said:

I'm not an expert on airflow or anything like that, but I can go by my experience and others with a similar pit as my 1975. When I first got my pit I ran it with the stack wide open, which had a very fast draft with the hot spot almost in the middle. What myself and several other 1975 owners noticed is that the food would come out with barely any smoke flavor, cooking times were very fast, and personally I noted my briskets were a little dry and crispy. Since using the stack damper and slowing the airflow and moving the hot spot to the right, my briskets have an incredible smoke flavor. They're not as dry or crispy either. I recently heard a top 50 pitmaster say the slower airflow keeps more humidity/moisture in the cook chamber creating a more tender brisket. I think each pit is different, so I think it's necessary to do testing with several different biscuit tests with different airflow settings, and then testing smoke flavor on short cooks. I cooked several 3" inch rib eyes with different airflow settings to gauge smoke flavor, because an oversmoked steak is very noticeable.

Here's an YouTube video I did on damper settings during a brisket cooking explaining the airflow and hot spot. Ignore the dirty smoke thing, I burn a clean fire in every damper setting, it's the slower airflow that gives the smoke flavor:

https://youtu.be/QClqddVHYNc?si=-7KGnyZX8UpWkEde

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That is a really good video. Very informative, thanks for sharing that.

Like how people up North/West/East comment on Texas pits

Y’all have some interesting thoughts fo sho

SkaterSmoker said:

I run my Workhorse 1975 with the stack damper closed 2/3 or 1/2 depending on the cook. It really depends on how fast your pit drafts. Do a biscuit test with the stack wide open and if your hot spot is in the middle, you can close your stack damper down to slow the airflow when needed and move that hot spot far to the right. When I went on a Texas bbq tour, a lot of the 1,000 gallon pits had the stack damper closed 1/2 to 3/4 since those pits drafted so fast.

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Listen to this man.

Headgear said:

That is a really good video. Very informative, thanks for sharing that.

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agreed, great video

ttkt57 said:

Listen to this man.

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Haha, I appreciate the vote of confidence!

Get’n Smokey said:

Like how people up North/West/East comment on Texas pits

Y’all have some interesting thoughts fo sho

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I’m curious what your thoughts are on this topic since you live in the area with so many offsets on display? I’m always looking to expand my knowledge. Thank you.