Firebox Vents Vs. Door

redblotch83 · Post by **redblotch83** » April 26th, 2017, 2:34 pm

Hi guys!

I built a 48" x 24" reverse flow almost 2 years ago thanks to y'all's help via plans from smokerbuilder.com. The last thing I have left for the build are the firebox vents. Hoping to have you guys help me make a decision about adding (or not adding) the vents. I've been cooking for awhile now (mainly Texas style briskets and pork butts with white oak), but it seems like my meat doesn't quite have the dark smoky bark that I've seen in a lot of pictures. I wrap after the stall with butcher paper, but I've seen stuff from Franklin's in Austin who uses the same technique that's much darker after a cook (but they also don't use reverse flow, they use traditional offsets - the only other variable which I obviously can't control since I built a reverse flow). In my cooks I control the temp with the smokestack flap and the door. Would you experienced pit masters think I could get more smoke on my meat if I just used vents? Or is this just a result of the reverse flow? Any advice or thoughts is welcome! Thanks again for everything!

-Rob

redblotch83 · Post by **redblotch83** » April 26th, 2017, 2:59 pm

Also wondering if building a proper fire basket helps? I currently just have a flat piece of #9 3/4" expanded welded on top of 3 pieces of 1" angle. Fire stays going really well and it's really easy to keep a solid temp. Wondering if what i've seen folks build in regards to fire baskets would help my cause. Keep the fire more contained? and not built up on a pile of ash?

mp4 · Post by **mp4** » April 26th, 2017, 8:09 pm

I don't think the fire basket would make a difference. I would think the wood type and temp has the biggest impact.

forty_creek · Post by **forty_creek** » April 26th, 2017, 8:54 pm

What temp you cooking at?
What's your BP Gap percentage vs your throat?
What size cooker?
Where's the stack located?
Will vents help, I would think so. You should be able to better control your temp (however your temp control is good)? Controlling your temp with the exhaust damper is opposite of how I operate my RF. I open my exhaust wide open and control temp with the FB intakes.
Now how does this affect smoke meat coloring? You may be getting a really clean burn from too much O2. Resulting in less smoke in the CC...maybe is my thinking. By restricting the exhaust I do not believe that will help with smoke coloring. Most pics appear darker due to lighting. I just deleted a pic last night of a chicken thigh. One was poor lighting which made the chicken look much darker than it actually was. The picture with better lighting looks like something from a cookbook. I do not have the pic on my phone. I will try to get it and post it soon (day or two). I didn't cook the chicken thigh either but it was cooked on my pit this past weekend.

My questions are just me thinking out loud. If there were intakes on the plans and the pit was built to the plans except for the intakes...I would definitely add the intakes. If you ever had the privilege of sitting and talking to some of these guys like OB1, their experience, science and math behind the proper build are something you cannot buy. However you bought the plans so I would personally stick to the plans. They do not draw plans without building and testing the theory first. Please do not take me wrong...I'm just downloading my thoughts.

I'm sure a much wiser more experienced SmokerBuilder will come along soon and see that I just went BTU out of my arse...

All that to say I would add the intakes. Make sure the bottom of your fire rack isn't below the intakes. Place your intakes as low as possible...IMO

Good Luck

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redblotch83 · Post by **redblotch83** » April 27th, 2017, 1:06 pm

Thanks guys!

All other things are to spec based on plans (BP Gap % vs throat, smoke stack diameter and height). Full plans are the 48" x 24" reverse flow smoker, square firebox on the right. Stack is located exact place as plans - direct center about 2 inches or so from the outside of the cook chamber on the same side as the firebox. I cook at 250 and it's really easy to keep temp, but maybe that's the case, maybe I'm getting too much 02 and it's such a clean fire that I'm mainly just creating heat. Most of the time (90% of the cook) I have the nice blue smoke coming out of my stack.

My reasoning for not adding vents is because a couple of the professional pit masters I was trying to emulate said the door was their biggest control element and they always cooked with it open. Since I've been cooking for a year and a 1/2, I've been able to hone in using the door and the vent on the smokestack. But maybe because the fire is getting so much oxygen, it's getting too hot, and thus most of my smoke is going out the firebox door as opposed to the smokestack. Because during a cook, the smokestack is maybe 1/2 an inch open at it's widest point.

So if I add the intakes, the plans suggest placing them essentially (1/2 an inch off center) of the firebox and 2 inches from the bottom. You suggest placing them as low as I can and to make sure the fire rack is above the top of the intake. How do these intakes deal with soot that builds up on the bottom of the firebox? Does that cause the fire to get choked off as the cook goes on? Or will the intake ensure a clean air path? Guess I can slap them in and do a test fire!

Thanks
-Rob

Post by **Rodcrafter** » April 27th, 2017, 3:12 pm

Its been my experience that, the longer I allow the meat to be exposed to the smoke and the seasoning I use is what makes the meat darker. Like paprika and sugar make a red tint bark. and black pepper and salt leave a blacker color. if I wrap it early it won't get too dark anyway.

forty_creek · Post by **forty_creek** » April 27th, 2017, 6:34 pm

Red, I would install the intakes as they are on the plans.
RC is dead on as always!
That's why he's:
the MAN
the MYTH
the LEGEND

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Post by **Big T** » April 27th, 2017, 8:14 pm

Post by **Rodcrafter** » April 28th, 2017, 11:47 am

Hey come on FC take a picture of you wearing your new apron.

Fishgod · Post by **Fishgod** » April 30th, 2017, 10:51 am

I am probably the last person to take advice from but I have watched a bunch of Aaron Franklin videos, and read his book. I have also looked at about every offset and RF build thread I can find. With that said I have been thinking about this one.
Aaron's smokers are built for flow across the CC at grate level. The FB is mounted high and he has a huge collector/stack at grate level at the other end. With his design the smoke/heat has to travel across the meat at grate level exposing the meat to all that wonderful TBS.
On your design which I see the stack is in the top right corner. Does it extend down into the chamber? What might be happening depending on the stack placement is that your meat is getting cooked mostly with the heat and little exposure to the TBS. Or at least not as much as Aaron's design. With the meat on the bottom shelf and you getting that good of air flow the smoke is coming out of the baffle plate up across the top and out. If that is happening maybe tacking a diverter on the top left to push the smoke down towards the grate. say a small plate angled 45 degrees towards the bottom grate. I would be an easy test and your not really altering your smoker much. Easily removable.

forty_creek · Post by **forty_creek** » April 30th, 2017, 11:52 am

RC, I'm gonna frame it!

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forty_creek · Post by **forty_creek** » April 30th, 2017, 12:00 pm

Hahaa I found the pics... I mentioned earlier in this thread

Lighting makes a tone of difference... I think I'm on the right thread. Red was talking abt color of meat after cooks.

Anyways these thighs were d-boned by my buddy last wkend at the gathering. They were hittin!

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Post by **Rodcrafter** » April 30th, 2017, 4:56 pm

They were great too. I need to work on my chicken cooking. You guys did really good on the chicken I had at the gathering

Making memories!

redblotch83 · Post by **redblotch83** » May 2nd, 2017, 12:01 pm

Fishgod wrote:I am probably the last person to take advice from but I have watched a bunch of Aaron Franklin videos, and read his book. I have also looked at about every offset and RF build thread I can find. With that said I have been thinking about this one.
Aaron's smokers are built for flow across the CC at grate level. The FB is mounted high and he has a huge collector/stack at grate level at the other end. With his design the smoke/heat has to travel across the meat at grate level exposing the meat to all that wonderful TBS.
On your design which I see the stack is in the top right corner. Does it extend down into the chamber? What might be happening depending on the stack placement is that your meat is getting cooked mostly with the heat and little exposure to the TBS. Or at least not as much as Aaron's design. With the meat on the bottom shelf and you getting that good of air flow the smoke is coming out of the baffle plate up across the top and out. If that is happening maybe tacking a diverter on the top left to push the smoke down towards the grate. say a small plate angled 45 degrees towards the bottom grate. I would be an easy test and your not really altering your smoker much. Easily removable.

Great thoughts. My stack is flush with the top of the CC. Do some people extend it lower into the CC? It might be neat to look into a "collector" type stack on the end. Has anyone done something like this with their build? Also, the diverter is a good suggestion too. My dad has a infra red camera, but he's in texas and I'm in california so we haven't had a chance to see how the air is flowing inside the CC. Hopefully soon! Thanks again everyone for the great advice (per usual).

Cheers!

redblotch83 · Post by **redblotch83** » July 12th, 2020, 5:21 pm

Hey guys!
I know it's been awhile, but I want to revisit this topic. Kids and work got in the way the last year or so, but with all this time off because of cover I'm jumping back into smoking again.

So, I installed the vents called for in the plans (24x48 cylindrical reverse flow with square firebox). Vents are 5.5 inches by 2 inches. One on each side. Since installing, I've had issues keeping the chamber low enough to smoke. If I close off the vents lower than 1" a piece my fire goes out. And if they're open larger than that, the chamber creeps up over 275 encroaching on 300. I'm trying a combo of dampening the smoke stack, but feel like doing that slows down the draw.

At first I thought it was because my fire was too low as I had originally built a grate style fire pit with expanded metal over 3 - 2" pieces of angle iron laid flat to give it a bit of a rise off the bottom of the firebox. After installing the vents I thought maybe my problem was that my fire was below the air from the intake, so I repurposed an old fireplace rack which now keeps the coal and my fire about 4-5 inches off the bottom of the firebox. I thought that would alleviate my problem of the wood not staying burning, but alas it has not. Any thoughts would be greatly appreciated. I hope everyone is staying safe and well in these difficult times!

Many thanks!

Post by **Big T** » July 12th, 2020, 8:41 pm

I'm not sure of your fire building method but you really want to concentrate on your coalbed more so than the size of the fire. I start out with about 8lbs of lit charcoal and then I put a split or 2 on top of the coals. I normally cook in the 250-275 range an it usually takes about 45-60 minutes to come up to temp. Depending on the amount of meat in the cooker, I normally have to add a split or 2 every 45 minutes or so. My intake position also varies depending upon the amount of food on the cooker but I normally don't have to adjust my intakes once I get it dialed in. The main thing to remember is that you have to make sure that you don't lose your coalbed or you have to rebuild it which can cause temperature swings. It also helps to have your splits be pretty close in size, I prefer them to be about the size of a beer can in diameter and just a little shorter than my fire basket.

Dirtytires · Post by **Dirtytires** » July 13th, 2020, 11:46 am

Also be careful about raising your fire too high as it effectively decreases the size of the firebox. Having the vents at or below the level of the fire does help and having more than one seems to help also. I wouldn’t mess with moving things again tho and focus on your fire.

Agree with big T tho, it’s the coals that provide the heat. Keep your coals healthy and don’t worry about the flames. As long as it’s not smoldering and throwing out black smoke you should be fine. Remember, the whole idea of closing down your vents is to starve the fire of oxygen so it burns slower....I would expect some of the flame to go out. Quite frankly, I’d be happy if ALL of my flame went out and I just had coals.

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