How much air flow on a backyard offset

[Lynn Dollar]

How much is too much ?


Here's a vid from Harry Soo when he visited Franklin Barbecue's pit room and talked with Max . Max explains how the first part of the smoker can not be used because of direct heat from the firebox, and how the best heat is at the stack end. Which would be where the air flow would be weakest but it would have the best convection


Vid should start with Max explaining



https://youtu.be/ebCGuEZPCOE?t=284


Now here's Terry Black's in Dallas, that uses Moberg smokers, and they're not using the first four foot of the smoker, putting splits in front to block the direct heat, and putting foil on the brisket to keep it from burning

Same thing at Creekside near Austin where Harry Soo also visited , they have to protect the brisket from direct heat



https://youtu.be/Jq3rltHR7UI?t=35

 

[Lynn Dollar]

Now that was on 14 foot , 1,000 gallon propane tank offsets.


Downsize that to a 20 X 40 backyard offset.


Here's some ribs I smoked at 275* on my Old Country Brazos, trying to go all Aaron Franklin and smoke with the FB door open. I first looked in on these ribs at 2 hours and they were bottom burned from direct heat due to too much air flow. They were on the stack end of the grate. Ribs were no where near done.


I had the same thing happen on a pork butt cook. I was getting direct heat into the cook chamber, might as well as had the meat over coals on my Kettle.



So I bought tuning plates, thinking they would protect the meat and continued to try to cook with the door open. Not a good thing, that was. I finally got smart and started using the smoker the way it was designed, and that's with the door closed and using the damper to control air flow. I've been happy with the results.

 

[Lynn Dollar]

Moral of the story, IMO, I think way too much is made of air flow on backyard smokers. Air flow and convection are not a problem, in fact, its just the opposite.

 

[SmoothBoarBBQ]

You've figured out what works for you and your cooker, but I think really you are likely running too large of a fire. I've run small offsets (Yoder Cheyenne 20x36) and I never had issues with the bottom side of the meat burning. That Yoder was a piece of garbage so I had to keep the firebox door open at all times or else it would suffocate the fire in the firebox. The damper was on the firebox door and it was mounted too high, so the heat would go from the fire and directly out the damper rather than into the cook chamber. haha The key to keeping a small offset running strong is a small, hot fire. Of course your mileage may vary.

Airflow is massively important when you're dealing with smokers, and that piece of garbage Yoder was a perfect example. People on this forum (and others) hounded Yoder for years before they finally admitted there was a problem with their design, and they have made new / redesigned versions of their cookers to address the drafting problem. The lack of airflow / draft made cooking on that smoker an absolute chore and a pain in the butt. So I generally will disagree with your notion that airflow and convection don't matter in backyard offsets.

 

[Lynn Dollar]

If you're pushing air through a 14 foot 1K propane tank, yeah, air flow is important.


On a 40 or 48" backyard smoker, nope. You need enough air to burn a clean fire.

 

[thedude9999]

If you're pushing air through a 14 foot 1K propane tank, yeah, air flow is important.


On a 40 or 48" backyard smoker, nope. You need enough air to burn a clean fire.

That doesn't mean airflow isn't important, it means your have different needs. You don't burn a small, clean fire without proper airflow. You don't pull the smoke and heat through the cook chamber without proper airflow.

I cooked on an OKJ Highland for a long time before upgrading to a better pit . Lack of airflow on that cooker (yes, I sealed it all up) was it's biggest problem, even more so than the thinner gauge steel.

 

[Lynn Dollar]

That doesn't mean airflow isn't important, it means your have different needs. You don't burn a small, clean fire without proper airflow. You don't pull the smoke and heat through the cook chamber without proper airflow.

I cooked on an OKJ Highland for a long time before upgrading to a better pit . Lack of airflow on that cooker (yes, I sealed it all up) was it's biggest problem, even more so than the thinner gauge steel.

Yeah, well, I said, you need enough air flow for a clean fire. Whatever that may be for that particular smoker.



But too much air flow will draw direct heat into the cook chamber and burn the meats. Which is why Terry Black and the other joint, used foil on their meats because that large smoker needed that much air flow.


Max even said that for the Franklin smoker, they got too much direct heat on one end, got the good convection on the stack end. A backyard smoker's cook chamber is too small for that.

 

[thedude9999]

I don't think there is a generic answer. They need enough based on your cooker, the type of wood you are using, how well seasoned it is, weather, altitude, etc.

I find it interesting to listen to folks like Franklin talk, but what applies to their cookers doesn't apply to what I do in the backyard. I don't cook with my door open, I cook with it shut and the vent's 1/3 to 1/2 closed on average. I get nice thin blue smoke, good temperature regulation in the 250 - 275 degree range, and most importantly, tasty BBQ.

 

[Shagdog]

On a direct flow, its not so much that there's too much airflow by the firebox, its just that its so dang hot! Airflow is a wonderful thing, without it your bark isn't nearly as good. My shirley has a ton of airflow, and that's never been an issue. The difference with the shirley is that its reverse flow. Even on that, the corner nearest the fire box just gets hotter. The bigger fire you're running, like say, to heat a 1000lb propane tank, the more heat you will have right out of the firebox. tuning plates help mitigate that, but its still an issue on direct flow.

 

[AUswimKC]

I think you’re missing your own point.

For those large cookers, they need a certain amount of heat temperature coming out of the firebox to make the whole volume useable. At those temps the end by the firebox is not useable.

For a backyard smoker, as others have said, you’re likely using too big of a fire. Everything in life is a compromise. Have full 100% airflow, build a much smaller fire with smaller splits and feed it more often. This is what I choose as it limits the chance of both burning the meat and burning a dirty fire. The trade off is more babysitting and maybe more fuel burned.

You’re choosing to build a bigger fire that can be controlled by limiting the air flow and that doesn’t need to be babysat as often. The trade off is a bigger chance of having a dirty fire or zones too hot near the firebox.

Neither is wrong. Neither is right. I choose A, you choose B. I also choose B on steroids when I choose to sleep at night and use the BGE, but that’s a whole different story.

 

[SmoothBoarBBQ]

If you're pushing air through a 14 foot 1K propane tank, yeah, air flow is important.


On a 40 or 48" backyard smoker, nope. You need enough air to burn a clean fire.

You're the guy over here burning your meat. Perhaps....just perhaps, you don't have it all figured out the way you think you do.

 

[SirPorkaLot]

Moral of the story, IMO, I think way too much is made of air flow on backyard smokers. Air flow and convection are not a problem, in fact, its just the opposite.

I disagree.

Draft (airflow) in an offset is everything.

Baffles or separation between the firebox and the cook chamber is key to even temps, not airflow

 

[Lynn Dollar]

I disagree.

Draft (airflow) in an offset is everything.

Baffles or separation between the firebox and the cook chamber is key to even temps, not airflow

I'm not saying that.


I'm saying its very easy to have too much air flow.



And I don't think its about even temps end-to-end........ its about the amount of direct heat entering the cook chamber.



I can get even temps end-to-end by the temp gauges, but then a biscuit test tells me I've got more direct heat on one end. Biscuit tells the real story.



I can also move the heat around inside the cook chamber, by how far I open the FB door. But the heat I'm moving around, is direct heat.



Notice Franklins backyard smoker has one temp gauge on the far stack end. That tells me , he's not even thinking about the FB end.

 

[Lynn Dollar]

I think you’re missing your own point.



For a backyard smoker, as others have said, you’re likely using too big of a fire. Everything in life is a compromise. Have full 100% airflow, build a much smaller fire with smaller splits and feed it more often. This is what I choose as it limits the chance of both burning the meat and burning a dirty fire. The trade off is more babysitting and maybe more fuel burned.

.

Yes, I understand that. I cut my splits down. And I work very hard at keeping my temp swings to a minimum. I even chart my smokes with Thermoworks Gateway.


When those ribs burned, I was shooting for 275*, or in that range. I was totally shocked to look at those bottoms after 2 hours.


They were burned from direct heat because I had the FB door open and using air flow to shove the direct heat into the cook chamber, the same burning Terry Blacks put foil on their meats to prevent, and what Max talked about on Franklin's pits.



I was trying to improve my smokes by increasing convection. What I have found, is closing the FB door and quit trying to ramp up the air flow, is far better . I'm not worried about convection. Smoker gets plenty of convection using air through the damper.

 

[ColoradoSmoke]

What kind of smoker do you have? Just curious.

 

[Lynn Dollar]

What kind of smoker do you have? Just curious.

Old Country Brazos.


I've had it a bit over two years , in learning how to use it, I researched old threads on this site and this one influenced me to cook with the FB door open. That end-to-end even temps could be obtained that way.



https://www.bbq-brethren.com/forum/showthread.php?t=213947


And it increased air flow, which also supposedly, would increase convection. But that did not happen, I got bottom burn on my meats and posted about it here, where others say they've had the same problem.


Marvda1 had it right then, he was cookin with the door closed , using the damper



If my splits were any smaller , I'd been using chunks


https://www.bbq-brethren.com/forum/showthread.php?t=271381


I don't think these backyard cookers need a lot of air flow. And that's an important consideration now that I'm thinking about upgrading.

 

[thedude9999]

Is this with or without tuning plates?

On a small cooker, running at higher temps can heat the tuning plates up quite a bit, and you end up with radiant heat cooking from underneath.

On my 20" Horizon, with the plates, I can can get the lid thermometers within 5-10 degrees, but the temperature at the grate is 50 to 100 degrees different, due to the radiant heat.

A small gap between the firebox and the edge of the plates helps (how much depends on the cooker). As does moving the fire closer to the door vs the cook chamber, if you have the space.

 

[Lynn Dollar]

The burnt bottoms were without tuning plates.



I did buy some plates from Old Country, decided they were more trouble than they worth and just stuck to rotating the meats.


I also discovered the Brazos ran a lot better with the door closed , and reducing the air flow. I think Franklin and his book and maybe John Lewis, have created too much hype about air flow and that was being applied to backyard smokers. That really became evident after I see how he's cut the air flow down on his backyard smoker.



But after doing a biscuit test, I'm starting to work with the tuning plates again.

 

[SmokyDick]

People overthink smoking in every way possible and make it harder than it needs to be.

 

[104timberwolf]

I use an old Brinkmann offset smoker. I’m guessing the cooking chamber is 16 inches in diameter. I bought a 1/4 inch tuning plate and place a large aluminum pan of water on top of that and under the food. I leave the dampers wide open in order to burn a clean fire. It will run at 250-275 consistently with tending. I agree that fire size plays a large part and I’m constantly monitoring the fire.