How do I reduce the amount of smoke exiting my oven

[Brian]

I’ve written about this before but I’m sill looking to see if there are any other solutions.

I have an issue with smoke and a neighbor who lives downwind. At certain times during the burn there is a lot of smoke. Not when it’s blazing but when it’s starting and when the flames have burned down and I’m letting it go to embers before adding, and just after, more wood. I have installed a 4’ chimney and the problem is not so much the smoke coming out of that, but the smoke that comes out the door. Open or partially closed it just comes out.

My neighbor and I are not adversarial. I have been in their yard when it’s burning and the smoke is unpleasant. I end up having to make arrangements to use it when they’re not at home. That’s just inconvenient.

My wood is seasoned and I check it with a moisture meter. It really doesn’t matter where the wood is burning, back front or middle, some always comes out the front.

Just wondering if I am doing something wrong or if there are any other suggestions I can try to address the issue.

And yes, as everyone I speaks to suggests, I have offered pizza, but unfortunately, that doesn’t hack it.

Thanks

[Yurii]

Hi Brian,
I do not have a solution for you, but may be a good idea to try. Smoke is unburned carbon, so when the temperature is not hot enough or there is a lack of oxygen, carbon escapes as a smoke. Once a bunch of italians were making a pizza at work, and they have brought a hair dryer with them. They used it to blow air inside of the oven to provide an extra inflow of oxygen, and they barely had any smoke. Now, I would be careful with this, as blowing air would cause oven to heat up too quickly and it might cause problems. So, perhaps put less wood and use a blow dryer to get the fire started - see if this helps?

NB: Although my wife loves pizza, she was quite apprehensive with me using her hair dryer on one occasion.

Cheers!

[bikerbudmatt]

You could try something like this:

Portable Starter

I’m not recommending that particular one, or even that style. But it sounds like you need more oxygen as your fire starts. This would avoid using (or borrowing) an electric hairdryer.

The bellows is a common fireplace accessory for this same purpose. It’s a necessary tool for a blacksmith, and it has just one use: to supercharge a fire with oxygen in order to increase the rate of combustion. The example I linked is a rotary-crank version of a bellows.

One subtle advantage is that you won’t be allowing relatively cold smoke (uncombusted carbon) to flow out the door, but instead you’ll be blowing it back into your kindling fire along with the oxygen that’s needed to combust it.

I hope this turns out to be helpful. You know you have a serious problem when pizza won’t solve it!

[bikerbudmatt]

Just bumping this post. Brian, have you had any luck with the smoke issue?

[Brian]

Thanks for following up.

I still haven’t solved the smoke issues. I had previously purchased “electronic bellows”

Amazon.com : FiAir - Air Blower/Fast Fire Starter for Charcoal Grills,...

It works pretty well, but not![enough

I’ve attached a few photos which shows what I’m getting (often, it is much worse than this). You can tell by the black at the top of the opening, that there is a lot of smoke coming out of the front.

Basically until it becomes a blazing inferno, I have smoke issues. I still wonder if I am doing something wrong. I was looking at one of your threads and read that it takes an hour or so to get to the right temperature. It normally takes me about 3 hours to get it up to 900+.

Kindling plus one log. Let go to embers. 2 logs, then to embers etc. Going to embers takes 30-45 minutes each time. This is one of the worst times for smoke. I just cannot see how I can get it up to pizza temperature in an hour or so.

Am I doing this wrong? Is this perhaps why I’m getting too much smoke. Plus why is 50% coming out the front rather than going up the chimney?

[MikeY]

Had a similar problem, which I addressed by splitting the logs into smaller pieces and burning those in the early going. Basically big kindling burns. Same amount of wood (and therefore same BTUs of heating) but with more surface area, it burns hotter and therefore cleaner. Keep splitting until the smoke goes away. Lots of small stuff versus fewer big stuff. Once the oven gets hot, anything I put in there goes off no problem, so can increase size of pieces.

Also, I think once the chimney warms up, the natural stack effect goes to work and helps to move the bad air out and the good air in, but again that takes time.

[bikerbudmatt]

Thanks for those photos, Brian.

I need to ask one very basic question, and please understand that I just want to eliminate some possible causes here.

Have you checked your chimney to be sure it is completely unobstructed? And the follow up question: If a damper is installed, is it completely open while you are firing the oven?

These photos remind me of fireplaces where the fire got laid and started with a closed damper or some blockage in the chimney. (And yes, that includes at least one firsthand experience… )

I don’t see in your photos the chimney itself, so that’s one of the reasons I ask. I remember you were asking about insulating it while you were building.

If for some reason your chimney isn’t drafting the smoke out while you are starting the fire, that means you have three things that would be going on:

1. Exhaust still has to escape, so it’s going to the only opening. That would be the upper part of the oven mouth, because fresh air can only get in to through the lower part if exhaust has to use that route to escape. (Think of a double-hung window, where you can raise the bottom to get cooler air into a room, and lower the top to let the warmer air escape.)
2. Because the oxygen supply is constricted, the fire can’t get enough oxygen to burn efficiently, so it takes a long time to reach your desired temperature.
3. And, because the temperature is too low due to being oxygen-starved, combustion is inefficient and so carbon-loaded smoke (which is evidence of unburned fuel) is escaping.

The reason for the chimney being placed where it is in the design is to create a separate escape route for exhaust at the highest point in the oven, but not so far back that it is ineffective. If you imagine a line dropped straight down from the back of the chimney, that’s the intersection point where you’ll find fresh air (loaded with oxygen needed for combustion) being pulled in by the draft from the exiting exhaust air. Think of it as a natural bellows, being driven at first by the heat of your kindling wood.

If you’ve already checked the placement and good function of your chimney, I apologize. I offer that question in support of the quest to get you on good terms with your oven, and your neighbor!

[Brian]

If a damper is installed, is it completely open while you are firing the oven<
Yes, I made that mistake the 2nd time I used the damper - won’t do that again.

I remember you were asking about insulating it while you were building<
That wasn’t me.
You let me know about the extended chimney and I installed it to help divert the smoke.

Here is a photo of the chimney. This really is typical. 50% going out the chimney and the rest coming out the front.

[bikerbudmatt]

Thanks for that photo, @Brian . The draw really looks anemic. I don’t mean to be a pest, but have you made sure that you have an unobstructed flue from base to top?

Another thought: I see in your photo the fire in the rear of the oven. Is that where you are starting it?

If you are starting it at the back, instead try laying your initial fuel just inside the mouth of the oven, just behind the opening for the chimney. That’s where oxygen is plentiful. Once you have a small, very hot fire going, you can try moving it to one side of the oven instead of pushing it to the back.

Again, these are troubleshooting questions—I just don’t know what you’ve already tried, so these questions are meant to get all the options out where we can talk about them.

Let me know, and thanks!

[Brian]

I just checked the chimney and everything is completely clear.

I normally start the fire in the middle but I’ll try a little bit further forward. I’ll also try MikeY’s suggestion of splitting logs into smaller pieces.

My neighbors are away for the next 3 weekends so I’ll get some practice in and report back. Thanks for suggestions.

[bikerbudmatt]

Rootin’ for you, Brian!

One supplemental thought: getting hot air into the chimney and flue will help draw air into the oven. Flame is a process that builds on itself, and ramps itself up.

Because you can’t use chemicals to start the flame (unless you’re finished with cooking food in it and just want to turn it into a nice fireplace ), you’re limited to using oxygen in smart ways to start, accelerate, and maintain combustion.

[BrickWood]

Plz don’t forget the single BIGGEST issue w/ smoke. The firewood.

I can’t tell you how many “Smokey” ovens have been cured with a MOIST firewood diagnosis.

Firewood can look bone dry on the exterior - but still retain a massive amount of water on the inside. Dry / Seasoned firewood for COOKING should be stored under a cover… and never be exposed to moisture. If your firewood is heavy (and not surprisingly light in weight) - it still has lots of moisture inside.

We even purchase our firewood (cooking wood) from a distributor here in Seattle. He keeps the wood in old hole-ridden retired shipping containers - Plenty of airflow, but covered… Other distributors even KILN DRY their firewood. Bug and moisture FREE!

Here’s a simple test to see if your firewood is the issue. Grab some specialty cooking wood (the kind restaurants use) and fire up the oven as normal. You should notice that the specially firewood has little to zero smoke.

Here’s another forum post about the topic -

My oven is a bit smokey. What should I do?

[dob]

I’m adding to this old topic because “Smoke & Neighbors” is exactly what I’m suffering from. Wonderful neighbors! But now I’m not a wonderful neighbor. We have closely set homes in our neighborhood and the smoke draws up and runs down the side of the houses. Their old windows let smoke in. I am going to try and solve the smoke coming out the front before I buy them new windows, but also like Brian, their backyard gets filled with smoke.
@Brian - I tried this and it worked. Fire and Forget it - it solved the smoke coming out the front because it creates a little draw around the door and it won’t let smoke leak out.
I’m excited to try really good cooking wood next. My firewood is not “surprisingly light” - great tip.
I came on to the forum this morning pre a Home Depot run to buy taller flue material and see if anyone tried a power fan in the draw to get the initial firing portion of the process to go faster (then cut the fan off to let the heat collect).

[kgondoly]

All good information. The one thing I would add is that a lot of the “smokiness” of wood is from the bark. If you watch the video above (I always use this technique) the first couple layers of the log cabin are small pieces with no bark. So if you’re splitting wood into smaller pieces make sure one split takes the bark off. Note: I don’t use fatwood though. It’s pretty smoky.

To minimize the smoke you need a roaring fire as quickly as possible. Once you’ve got the inferno going you can add wood with bark with minimal smoke.

OK, I lied, I’ll add a second thing. I use a propane torch to light the kindling. It provides plenty of heat to light the wood and I can move it around easily to light a large amount of kindling quickly.

[Brian]

@dob. Your information was very timely. I got it yesterday and I was planning to fire up.

The video was great and I tried it out. That oven fired up very quickly. It was dark outside so I could see the smoke as well as I would have liked, but it definitely seemed like it was a lot less.

As @kgondoly says, once you get the file blazing there is little smoke. In the past, the smoke problem tended to raise it’s head when I let the wood burn down to embers then add wood to bring up again - per the Brickwood Oven instructions.

This brings me to a question for Brickwood. The instructions say burn, reduce to embers fire up again twice before going to final burn. Using the Fire & Forget method, it comes up to temp incredibly fast. As long as the brick is dry, is there any reason not to use this method. i.e. would it damage the brick bring it up to 900 degrees so fast?

Even before the Fire & Forget, I had managed to get the smoke way down for my first attempts. However, I can’t shake my neighbor’s memory and she is intransigent and not open to my protestations that it isn’t as bad. She does work with me and would tell me when they weren’t going to be at home. That used to be a lot, but with COVID…

BTW, I do have a tall flue (Amazon).

Again, thanks for the link to the method. Barring any potential to damage the brick I’ll continue to use that.

[Anaelezp]

Hey. I don’t know if you’ve tried this but I had a logger bringing us wood and told us that bark brings out smoke. Boy was this true with us! My husband chopped all the bark from our wood and the smoke drastically went down. Still some but not like it was.

If you have bark might be worth a shot in chopping those pieces off.

[423tommy]

I am also very curious about getting the temperature up to fast by the lite and forget method. I’m afraid of thermal shock. Especially in the winter were the outside temperature is cold. It would be hard to repair any bricks if that would happen.

Any opinions would be greatly appreciated.

[BrickWood]

I watched the (very long) Light & Forget video on YouTube. The method is sound - but my biggest concern is… What if ALL that wood ignites a lot faster than anticipated? What if all that wood ignites at one time on a cold oven? That is a recipe for surefire Thermal Cracking.

I’m not poo-pooing the idea of Light & Forget - it’s a great idea… I’m just concerned about thermal shock on your new oven. It only takes an hour to heat-up your oven… I usually spend this hour cleaning up the yard… mowing… weeding or even on occasion - playing w/ the boys.

[bikerbudmatt]

I also watched the FIre & Forget video. I think the methodology is sound, during the warm months and if you are firing your oven regularly.

I do believe that @423tommy is right to be concerned about doing this in the winter, and to that I’d add that if it’s been five days since there was a fire in your oven, I’d be careful about this method.

On an oven that is carrying some residual heat, I think this works because the “sled” is bolstered by heavier splits that don’t catch right away. In my mind the rough analogy is to a pilot light versus a burner. The pilot actually warms an enclosed space, but it’s the burner that really heats it up. The larger chunks of fuel catch later, after the bricks have had a chance to start expanding.

Again, though, I wouldn’t try it on a new oven or one that isn’t already carrying some residual heat from a previous fire. And definitely, not in cold ambient temperatures.

[423tommy]

Thanks all for your advice and confirming what I was thinking.