How much air flow on a backyard offset - Page 2

Lynn Dollar · 08-27-2020, 04:00 PM

Quote:

Originally Posted by ColoradoSmoke

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/s...d.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/s...d.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 · 08-27-2020, 04:16 PM

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 · 08-27-2020, 04:28 PM

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 · 08-27-2020, 04:30 PM

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

104timberwolf · 08-27-2020, 05:29 PM

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.

Lynn Dollar · 08-27-2020, 05:54 PM

BTW, what's helped me the most, is the LSG Fire Basket.

My FB is 20" long. The LSG basket is 12" long. This has enabled me to keep the fire away from the cook chamber, cutting down the direct heat.

That's also when I began smoking with the door closed.

NYC 'Que · 08-27-2020, 05:57 PM

The amount of required airflow is relative to the size of the fire. Don’t care if it’s a 30 gallon smoker or a 30000 gallon smoker. Science is science.

Sent from my iPhone using Tapatalk Pro

NYC 'Que · 08-27-2020, 05:58 PM

Quote:

Originally Posted by SmokyDick

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

Amen and thank you.

Sent from my iPhone using Tapatalk Pro

NYC 'Que · 08-27-2020, 06:00 PM

Quote:

Originally Posted by Lynn Dollar

BTW, what's helped me the most, is the LSG Fire Basket.

My FB is 20" long. The LSG basket is 12" long. This has enabled me to keep the fire away from the cook chamber, cutting down the direct heat.

That's also when I began smoking with the door closed.

I know I’m going to get crap for this but that fire basket was designed to compensate for a flawed fire box. You’d never need such a grate in a round firebox.

Sent from my iPhone using Tapatalk Pro

Rockinar · 08-27-2020, 09:08 PM

The lesson you learned is not about airflow. The lesson you learned is why people should not buy a 36" offset and everyone recommends 42"+

I agree with SmokeDick. People WAY over think everything.

busmania · 08-27-2020, 09:34 PM

Quote:

Originally Posted by 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.

I built my smoker pretty much specifically to eliminate the burned bottoms I got using my yoder wichita because of the radiant heat. I find slowing the airflow down to where I can still burn a clean fire helps the quality of my food tremendously. In fact, my next build I will work to find the perfect balance of minimal air flow (Which on an offset is still a ton of air flowing over the food) and a clean fire by how wide the fb to cc hole is and how big the exhaust collector hole is on the chimney side. I don’t use tuning plates either, I have almost even temps left to right. In short, I do think too much air flow is as bad as too little. But I have no proof or anything which is why my next build will be built to specifically test these theories.

SmokinAussie · 08-28-2020, 04:14 AM

Quote:

Originally Posted by SmokyDick

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

Naaah. It's harder than it needs to be which is why people overthink it.

It's why we're here bro!

Cheers!

Bill

marvda1 · 08-28-2020, 09:50 AM

@lynn dollar, how far open did you have the firebox door? pictures that i have seen of people that use the firebox door, have the door open only about 1/4 of an inch or less.

Lynn Dollar · 08-28-2020, 10:57 AM

Quote:

Originally Posted by marvda1

@lynn dollar, how far open did you have the firebox door? pictures that i have seen of people that use the firebox door, have the door open only about 1/4 of an inch or less.

That was about 1 1/2 years ago and I've slept a few times since, but I believe at that time I'd found 2" open to be my sweet spot.

Although I'm pretty happy with the Brazos, my only interest in this air flow question now, is that I'm looking at possibly upgrading. Trying to figure out how much there's to be gained for money spent.

Ya know, if Franklin's called me right now, asking me if I was ready to buy, IDK what I'd do, I would probably decline because " when in doubt, don't " . For sure, I would ask a lot of questions.

I had ruled out an LSG 24 X 48 because it used tuning plates. Now I'm not so sure tuning plates are a bad thing.

I just have a whole lot of questions to get answered before I drop that kind of money. I'd hoped this post would generate some discussion that would help.

Lynn Dollar · 08-30-2020, 07:26 AM

Something else I need to bring up here about my Old Country Brazos and how it differs.

There's a baffle between the FB and cook chamber. It chokes down the air intake. At its widest point , there may be 3 " of air intake.

This creates the Venturi Effect, the speed of the air flow increases. And highly likely, it shoots into the cook chamber. Opening the door increases air flow through the constriction, and really shoots the heat to the stack end.

So what's happening with my Brazos, being able to move heat end-to-end with the FB door, is probably not applicable to other smokers that do not have that severe air flow constriction.

Your results may vary.

And there's definitely a difference in heat out of the FB. The vids I've posted from Franklin's pit room and the Moberg smokers, back that up. In the Franklin pit room they call the heat " direct heat " . Others may not.

Mad Scientist on YT talks about this here, and if Y'all understand where he goes with this, then fill me in, its over my head. But he's talking about direct heat.

Vid should start at about 44 minute mark.

https://youtu.be/9fb9gEQ5804?t=2509

BTW, the Vortex in your Kettle has a Venturi Effect. It restricts air flow through the Kettle, air flow speed increases and shoots up to the dome, where the curvature of the dome then circulates it through the Kettle, creating extreme convection and improving your wings. Its not the high heat that makes the Vortex work, its the increase in convection that it creates. Though the dome of the Kettle will really get hot from the direct heat shooting up, the air cools quickly as it flows back down.

And the Vortex works even better, if you line the charcoal grate with foil and cut out inside the Vortex, to direct more air flow through the Vortex .......... and keeps your Kettle cleaner from grease drippings.

08-27-2020, 04:30 PM	#19
SmokyDick Full Fledged Farker Join Date: 07-13-18 Location: KY Name/Nickname : Rich	People overthink smoking in every way possible and make it harder than it needs to be.
	1 members found this post helpful.

08-27-2020, 05:54 PM	#21
Lynn Dollar is One Chatty Farker Join Date: 01-19-18 Location: Oklahoma City Name/Nickname : A man named Lynn	BTW, what's helped me the most, is the LSG Fire Basket. My FB is 20" long. The LSG basket is 12" long. This has enabled me to keep the fire away from the cook chamber, cutting down the direct heat. That's also when I began smoking with the door closed.
	1 members found this post helpful.

08-27-2020, 05:57 PM	#22
NYC 'Que On the road to being a farker Join Date: 05-07-20 Location: Bronx, NY Name/Nickname : T.J.	The amount of required airflow is relative to the size of the fire. Don’t care if it’s a 30 gallon smoker or a 30000 gallon smoker. Science is science. Sent from my iPhone using Tapatalk Pro __________________ Workhorse Pits 1975, MAK 1 Star, PKTX, Weber Kettle 26

08-27-2020, 04:16 PM	#17
thedude9999 On the road to being a farker Join Date: 05-24-20 Location: Toronto,ON Name/Nickname : dude	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.

08-27-2020, 04:28 PM	#18
Lynn Dollar is One Chatty Farker Join Date: 01-19-18 Location: Oklahoma City Name/Nickname : A man named Lynn	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.

08-27-2020, 05:29 PM	#20
104timberwolf Full Fledged Farker Join Date: 11-02-13 Location: Montgomery, Alabama	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.

08-27-2020, 09:08 PM	#25
Rockinar is One Chatty Farker Join Date: 07-19-13 Location: Houston, TX	The lesson you learned is not about airflow. The lesson you learned is why people should not buy a 36" offset and everyone recommends 42"+ I agree with SmokeDick. People WAY over think everything.

08-28-2020, 09:50 AM	#28
marvda1 Full Fledged Farker Join Date: 08-21-12 Location: saginaw, texas	@lynn dollar, how far open did you have the firebox door? pictures that i have seen of people that use the firebox door, have the door open only about 1/4 of an inch or less.

08-30-2020, 07:26 AM	#30
Lynn Dollar is One Chatty Farker Join Date: 01-19-18 Location: Oklahoma City Name/Nickname : A man named Lynn	Something else I need to bring up here about my Old Country Brazos and how it differs. There's a baffle between the FB and cook chamber. It chokes down the air intake. At its widest point , there may be 3 " of air intake. This creates the Venturi Effect, the speed of the air flow increases. And highly likely, it shoots into the cook chamber. Opening the door increases air flow through the constriction, and really shoots the heat to the stack end. So what's happening with my Brazos, being able to move heat end-to-end with the FB door, is probably not applicable to other smokers that do not have that severe air flow constriction. Your results may vary. And there's definitely a difference in heat out of the FB. The vids I've posted from Franklin's pit room and the Moberg smokers, back that up. In the Franklin pit room they call the heat " direct heat " . Others may not. Mad Scientist on YT talks about this here, and if Y'all understand where he goes with this, then fill me in, its over my head. But he's talking about direct heat. Vid should start at about 44 minute mark. https://youtu.be/9fb9gEQ5804?t=2509 BTW, the Vortex in your Kettle has a Venturi Effect. It restricts air flow through the Kettle, air flow speed increases and shoots up to the dome, where the curvature of the dome then circulates it through the Kettle, creating extreme convection and improving your wings. Its not the high heat that makes the Vortex work, its the increase in convection that it creates. Though the dome of the Kettle will really get hot from the direct heat shooting up, the air cools quickly as it flows back down. And the Vortex works even better, if you line the charcoal grate with foil and cut out inside the Vortex, to direct more air flow through the Vortex .......... and keeps your Kettle cleaner from grease drippings.