Smoke Collectors: Do They Make a Difference? | Mad Scientist BBQ 

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When I hear about this talk about collectors vs no collector and stack heights etc etc I tend to think of hotrod car engines and headers. Even though they're separate beasts and it's comparing apples to oranges so to speak there could be some similarities between the two. I know that headers are supposed to help allow an engine to run more efficiently and have better exhaust flow and there's many different header and exhaust configurations and diameters for different engine setups depending on what you're particular engine is built for. There's headers with collectors on the ends where the actual exhaust pipe bolts on and some headers are shorter with short collectors and larger diameter tubes to get better flow for higher horsepower higher revving engines and there's longer tubes with longer collectors and smaller diameter tubes that's supposed to be better suited for a mildly built engine that makes it's torque and horsepower in the lower RPM range and everything in between. Does any of this correlate with offset smokers? I don't know but some of the same principles may apply and relate. Like for instance, a popular trick for getting better exhaust flow from a set of headers on a vehicle or exhaust pipes on a motorcycle is to wrap them with thermal wrap which traps more heat into the exhaust which is supposed to help the exhaust gases to be scavenged more efficiently, higher heat within the exhaust flows easier and this same concept might relate to the exhaust stack on a smoker. If the exhaust stack is insulated it just might allow it to flow better, it would be interesting to test. Anyway, I just wanted to throw this out there because I've studied vehicle and motorcycle exhaust systems and concepts for many years(I'm still no expert) and maybe some of the same philosophy from one can benefit the other.

I personally think the collectors draw more air efficiently. I built my smoker and put a collector on it and I find often I have to close the damper on the exhaust bc it is just drawing so much. Like you said it’s easier to fix too much air flow vs not enough. Cool video man keep it up.

The bloopers are great, thank you for the compilation!

By restricting the collector you increase the dwell time and positive pressure in the cook chamber. It is slightly different than just choking the stack back because it slows down the convective effect in the cook chamber but can still maintain a good draft at the same time. Kinda like having one foot on the brake and one on the gas at at the same time. I have been experimenting with this on my 250 gallon and it has helped me get better heat uniformity across the cooking grate while still maintaining a clean burn.

So let me share some light on the Collector The Collector actually decreases the air speed in the chamber, If you could actually measure the air velocity in the chamber in multiple spots, you would see the air SPEED difference between the two, this results in a more uniform air velocity in a smoker with a collector vs one without a collector. Now does this difference actually make a difference.............Well I dont actually think so, BUT the if you used the whole cooking surface of the smoker I would say then yes you would see a difference.

You should analyze your Brazos the same way. Make a 2 foot stack extension for it. Measure the temp diff on the stack end of the Brazos with the ext on and with the ext off. When air flow is increased in the Brazos, the stack end heats up. IMO, that's due to air not being able to exit as fast as its drawn in. And yeah, there's a baffle in the Brazos that mucks things up, but that simple test will show the value of a collector. I had a Brazos.

Another great video...really enjoy the science, thanks for the information. My first offset is being built. Looking forward to using it and documenting it. Your videos will be a big help, I'm sure.

ive been saying for a while now (having recently had offsets with, and without collectors) that i think they are as much fashion as they are measurable function. as i've not noticed any differences in my cook process or results. BUT if there are differences, i'd imagine they are more mechanical than they are thermal. in that the differences are HOW the smoke travels rather than its temperature. great vid anyway. i figured you'd be the first one to approach the subject.

Great video. I suspected the collector wouldn't do much in terms of airflow. But thing I've experienced with smokers crafted out of pipe and thought I saw here as well is that those with no collector is more prone to a hot spot directly in front of the stack. Typically without a collector, that stack is not set back 6 inches from the chamber. They take a 90° turn only an inch or two inches out. This can make it a bit more of issue for smaller offsets where useable space is limited.

Cool thermal camera shots!! I hypothesize that the collector functions to move a portion of the turbulence of the air going up into the stack to the space inside the collector, instead of over the grates, resulting in more even cooking. I'd like to see a test where instead of stuffing the collector full of foil, you cover the entire collector intake surface with a sheet of something (cardboard?) that has a hole in it the same diameter as the stack. This would simulate no collector with the same size stack. Then do one biscuit test with the collector and one with the restrictor sheet in place. That might provide results more relevant to cooking.

I have a homemade offset, 48" x 24" with a 24" cubed firebox. I have a tall exhaust stack using 6" tubing, and I did not build the smoke collector, just made a 90 degree angle cut and fashioned an elbow, welded it to the center of the exhaust side head like your Brazos. I have been thinking about modifying it and adding a collector but now I think I won't. Thanks for taking the time to do the test, I won't worry about this anymore.

Man, this video is almost exactly what I needed today. I smoked a pork butt today in the cold rain for 5 hours. I am finishing it in the oven until it reaches 205. Keeping a fire steady in rain is difficult, as was the high wind messing with my temps every few minutes. A fire management video in bad weather would be most welcome, love your work!

Good test. You should look into adding a velocity stack to an offset smoker. I have never seen one implemented and I wonder if there would be a noticeable increase in airflow.

My thoughts for collectors are that they help extend the hot spot of the exhaust away from your meat. Therefore you get more cooking space and less potential of crispy bits on that end.

For more precise measurements, use a tripod (one with a clamp) for the phone, and mark specific spots on the smoker to focus the infra-red. That way, you get the exact same points each time.

Great video, I really like the thermal camera. I would love to see you show the thermal camera on the new pk too. I'm curious to see how well the aluminum distributes the heat.

I was waiting for this one! Thanks for putting together a great video on a interesting subject!

Thank you once again for another great and thorough video.

I wish there was a way to capture airflow across all of the grates at different points . . . or even the airflow out of the stack. I suspect you're right, however, that length of the stack and diameter are what matter most. It seems to me that it would be neck-and-neck between the two styles, except maybe the last 1/3 of the grate towards the collector, where I think the draw would be more even across the grates. I don't have a collector system on my pit, and I definitely have a hot spot right near the stack. Great video, as always!

Thanks for the experiment and braving the Cold! That camera is pretty cool! You can also use it to check for leaks at your doors, windows, ductwork, etc :)

Great information as always. What are your thoughts on stack extensions? I have had a Pecos for the last couple years as my starter pit. I live in Florida and it’s always hot here so I find it difficult at times to get enough airflow when cooking below 300 and end up having to use a box fan to keep air moving in the right direction. Do you think attempting to use some type of extension would help? Or do you have some other tips? Thanks for what you are doing, I’ve learned so much and love the BBQ results.

Love the videos. Question: Is the "collector" a well-known feature/add-on? I was waiting for the part of the video where you explain/diagram the idea behind it. What's it supposed to do? Never heard of it until today but the video seemed more of a cold weather question than a smoke collector... who knows maybe I just missed a part or maybe I just wanted more :) Love the channel, you do great work!

i just did a smoke for the first time yesterday and it only got above freezing for like the last 2 hours of time, it was also my first time using the Pecos smoker got to say i was happy with it never had a problem with to much heat

Gotta consider the mass of metal and the volume of air between hit plates. The smoke collector has less air volume (air is an insulator) than the cooking cylinder so it heats up more despite being further away from the fire box. Same reason the bottom of fire box is lower than top. Would be interesting to get air temps along the cooking section..

I use my offset, in late fall and winter, for cold smoking pork bellies, for bacon. I use natural lump charcoal for fuel, close the chimney, open firebox vents, and open the grease drain door (just about below the chimney) for air flow. The little bit of heat carries the smoke UP, into the chamber, while the trapdoor moves most of the heat out. Works great.

The collect is supposed to ad a small amount of space to “collect” the hotspot on the grate closest to the stack and reduce its size is what Texas told me

Thank you Jeremy for the video.. i would be curious to see the infrared on a Lonestargrillz 20 x 42 offset since it uses crossflow technology

I’m building a 500 gallon pit w/ fully insulated fire box. I’m torn between a collector or a 90 degree elbow pipe, then a reducer, then the smoke stack. What are your thoughts on the elbow vs collector? Look up Texicana BBQ’s How to build a 1000 gallon smoker” for reference. In the video, Cen-Tex Smokers use an elbow rather than a collector.

Love the videos … I hope you read this note and go on to test what I’m about to note: the purpose of the collector was not exactly for the reasons you were testing for … but rather: a.) ensure smoke was exiting at grate level .. b.) allow meat to be placed right to the edge of the chamber and grate … without … c.) avoid overwhelming smoke taste of meat at chamber end. So IMO, a better test would be regarding taste and bark. You need to test against for example a Klose … or a Jambo which both offer a different theories on chamber exit.

Great video. I appreciate the old school data based approach. As a backyard cook my brazos produces amazing food. I see people making mods to add a collector but I rather spend that time an energy cooking. Lol. At the end of the day nothing beats mastering fire management

This is why I subscribe to your channel. Great content! I like your honest feedback. Please do more of these!!!!

I love it when you run tests!

Ha ha.. Makes me wonder about the draw on my Horizon Ranger (Has the horizontal and Vertical smoke boxes) though I can always dial it in where I need it.

Stack size matters. Great video. Kudos to anyone that can afford a FLIR camera for the heck of it. 🍻

I was just wondering if i had missed your videos, was pleasantly surprised when i opened the app

Seeing the thermal camera on the semi insulated fire box really makes me wonder about that vs a regular firebox (workhorse pits specifically). Cant wait to see your thoughts on the workhorse when you cook on it.

Looks like smoke (airflow) in relation to temperature for the cook to me. Nice demonstration test!

I put a collector on my Oklahoma Joe and it made a noticeable difference in airflow and controllability, it's still a cheap smoker, but I believe it works as good as a cheap smoker can work. I enjoy your channel and have learned a lot from watching, keep up the good work and most of all, have fun

So I’ve always heard mesquite wood burns hotter than other wood. Could you do an experiment to test this. Not sure if this has been done before or if there is a way to even test this but always have wanted to know. Love the videos keep up the great work.

The temperature difference may be the handle attachment operating as a heat sink? There looks to be a temp difference between the lid and the body which suggests less heat is leaking through the lid

I would think the collector is to manage smoke flow across the entire cook surface evenly. Help reduce stagnant areas of air in the corners and higher flow in the middle. Lay a brisket front to rear all the way to the left and test the brisket without a collector and the smoke and possibly the moisture would be different between the middle of the brisket versus the ends. Test may be better with three chickens testing the middle chicken against two corner cooked chickens.

Curious to see high exhaust vs cooking grate level. Also if tuning plates make it cook different. From the heat being under the meat vs on top.

Temperature is one thing, but air flow is another. It would be interesting if there were a way to measure the velocity and pattern of the airflow at grate level on two identical smokers, one with the collector and one without. It would be like a wind tunnel test. Some feel you get a more uniform velocity and pattern of air and smoke across the entire grate with a collector. But it is a theory that would be interesting to quantify if it is possible to do so.

I’m from southwest Michigan and I look forward to firing up my offset when the air is crisp and snow on the ground. I like to heat my splits up in a heated barn for a few days before I cook. Not sure if it actually has made a difference. I keep my wood covered well outside, I would think warming it up a few days before might. Or just excuse to make more fires... happy cooking!

Please do make more BBQ videos in snow. It's really looks like an ice on the cake from Australia.

Do you have a guess for how much the stack weighs? Looked heavy, but I’m wondering if I can lift it myself. I got the FS80 since the stack on the 120 was too tall for the garage, but figure if it’s doable I may try to call to switch to the 120

You should try this test with the Goldees offset and retro fit a smoke collector on it to test both. Since there is no immediate heat would there be a different result? would be interesting to find out….

Love the videos man thank you

I've been waiting for this video, you teased it so long ago!

The half Venturi on the moberg stack makes a big difference

I have a large pit my boy made in ag class, it's an offset reverse smoker. 12" pipe cut in half added 10-12" in the middle making it oval. It has a tal 3" diameter stack. It's very fire hungry, I run wide open and there's a straight stream of smoke coming out. A buddy thinks I should go to a 6" stack for better flow and that will help my fire last longer. Thoughts?

I really enjoyed the video! I do believe that the video was missing how the collector evens out the temperature from front to back (i.e. from base of door to back wall) . I can imagine that designs with no collector have a bigger temperature difference in this regard.

Recently was considering adding a collector to my pecos. Was in the early stages of research so this video came at the perfect time for me. Thanks!

God bless you for what you do. I don't cook on an offset, so anything else I say would be speculation!

What kind of wood are you using to smoke your collector ho ho good info thanks

That unintelligible word that you said right in the beginning sounded exactly like "good morning" in Romanian. I had to check twice if the audio is from this video lol. Keep up the good work!

Even if it doesn't do anything, it looks cool...these are some of the best looking pits I have seen.

Been waiting for this video. Thanks Jeremy

Appears the loss of heat from the firebox to the stack is quite a lot! Is that normal for most offsets or not? How about on the Franklin?

One quick question. Do you like offset vertical smokers?...I really enjoy your vids

What about the Lone Star Grillz with their shorter Square shape stack? They say the square shape draws more than round therefore doesn't have to be as tall as round! What are your thoughts Jeremy?

Cool experiment thank you sir 😊

Jeremy what brand of torch are you using to get the fire going?

Straight logical thinking on this, but when I think of flow path it makes sense that when moving air hits the back wall where the smoke stack sits that it can create a turbulent environment around the exhaust exit. Logically thinking, a collector could move this area out past the cooking area and allow a more smooth entrance into the exhaust pipe/smoke stack. Therefore potentially eliminating this area of turbulence in the cook chamber affecting the convection and even cooking. I would also imagine that a rounded end with a collector or a large exit that transitions into a smaller stack might even provide greater flow. I would say, without data, that a rounded end with a collector could create better convection/air flow that a flat end with a collector strictly due to the smooth transitions into the exhaust. I think of a river with a partial dam and the eddy’s and hydraulics that are created up stream of the dam. These statements I’ve made are literally only theories and I have no actual data to back them up, but logically it makes sense.

How would adding thermal mass to the cook chamber on the smaller cheap offset smokers possibly effect the variations in temp? I’m not talking adding pans of water, but say adding a concrete block or two, no added humidity, just added mass absorbing and releasing heat. Thanks

Loved the thermal camera, looked The Predator bbqing

In terms of air flow, an elbow paired with the proper stack dimensions would be best. Moving air does not like sharp corners. A collector like that would probably create turbulence at the bottom of the collector before being drafted upwards.

You finally got your hands on a FLIR 👍🏻

Hi Jeremy, This is for purely informational purposes. I’m not sure if you have your thermography certification or not but as a certified thermographer I thought I would share some information with you so you can use the information for future tests. Unfortunately, infrared cameras cannot detect through metal surfaces. It will only be able to tell you the temperature readings on the surface of the metal at different locations of the smoker and in no way is it possible for it to give accurate internal temperature readings of the smoker. The infrared definitely gives a nice touch to the video although I wouldn’t rely on it in this scenario for accurate results. Perhaps this is why you get that cold spot at the bottom left corner of the smoker. This would be most likely due to the idea of heat rising as well as draft from the chimney pulling air and heat away from this area. I enjoy your videos and look forward to seeing what you do next! Thanks!

Can you do an experiment for brisket with silver skin on and off. I think it might make the flat more juicy leaving it on holding in more fat maybe. Everyone always cuts it off except on beef ribs. Thanks 😊

I thought it was cold today when I was grilling in South Florida. I forget there are places where it’s actually cold.

So, what are your thoughts on a reverse flow set up?

When a Predator stares at a smoker trying to figure out if it will be his next prey.

Have you used that thermal camera on a reverse flow vs regular offset?

I am building a smoker at the moment but not sure what size stack to have??? Would 6inches be enough for a backyard smoker. Its 150l cook chamber.

I think when blocking off the collector you should make the surface as smooth as possible to ensure the airflow doesn’t get disrupted by the uneven foil edges, that might make a difference to how it performs?

Where do you get one of those torches to start the fire? I need one of those

I don't believe there will be enough of a change to say yes or no, the smoke will flow. I have a reverse flow smoker designed and built by Cajun Custom Cookers out of Moorehead, Minnesota it's a NSF Certified offset smoker, it's more efficient than my Brinkman offset. It takes my cook time on 6 - 10 lb pork roast from 9 to 10 hours to 6 1/2 to 7 hours.

Awesome vid! This is why I watch your channel: examining whether or not long held bbq beliefs are true or not.

What in the tarnation is a Celsius?

Good stuff mate

I've noticed that it's been much easier to keep a consistent temp when it's much colder outside.

FYI when using thermo imagers, the more reflected a a surface is the more of an inaccurate reading you will receive. For example place a strip of masking tape on a mirror and view it with a thermo imager. The temp reading will be 100% more on the reflected surface vs the masking tape

I just love the smell of oak fire.

Man those fatstack smokers look super nice. Been waiting on a workhorse 1969 since September. Build date in march. Really looking forward to upgrading

I know it's a pain to change things up, but I think that a biscuit test with both configurations would be worth doing.

On a reverse flow, the collector is heated by the burn box. Epic fail of coverage here.

Have you ever done a video doing a comparison between smoking a coil of sausage and BBQing a coil a coil of sausage with peppers and onion's great for super bowl

Just can't imagine cooking in the snow!

Right now I think that it won't make a difference in air flow by much but it will cause more of a hot spot right before exiting.

I have the theory that smoke collectors do not work as they should just because the opening is centered and above the cocking grate. The stack opening with no collector is placed most of the time below cooking grate to force hot air and smoke go down then drawn out. I wonder if a smoke collector is placed with the opening below cooking grate would really do its funnel function to smoothen the exit of the smoke.

have any info or background on the open range good-one by chance?

Really cool video. Just a note of why there might be that "random" cold spot. Is it possible that side of the door is not as sealed as the rest of the door? If there's the smallest of openings on that end of the doors cold air could be getting sucked in from the draw of the stack, thus creating that small little cold area. Just a thought. Keep up the great videos and looking forward to seeing a brisket cook on the Fatstack!

It looks like jeremy has a stable of bbq smokers. Lol

I've taken a moment to analyze the data in the video. The only thing it has revealed to me is added friction from the aluminum foil being stuffed in the collector. To me, this experiment did not show the advantage vs disadvantage between the collector concept and more conventional straight pipes. Also, the temperatures were only taken on the X,Y plane. The collector operates in the Z plane.

Have you gone euro using Celsius? We like Fahrenheit here in America!

What flir are you using?

What if someone made a smoker with bubble caps on reverse flow tray to keep water in tray?

Your lid is probably drawing in a small amount of air at the far end where that cool spot is...