Let's talk soot, baby! It's the Hot Topic of the week. Many of you have sent in questions wondering why your LavaBox is producing soot. Understandably so—it’s often understood that propane and gas-fueled fires do not (or should not) leave behind sooty black residue.
Is it a defect? Does the regulator need adjusting? Is it user error?
As always we’re here to give the people what they want, so let’s talk science and soot.
Your Campfire In A Can Isn’t Broken—Soot Is Expected!
To save you the sweet details if you’re in a rush I’ll answer those last few questions upfront: No, producing soot doesn’t mean your LavaBox is defective. You do not need to adjust the regulator due to any soot you might see left behind after use. And you’re (most likely) not doing anything wrong!
In fact, that bit of resulting soot you may be seeing is by design. The good news is that it’s to be expected. No need to call in the LavaDoc. The bad news—if you can’t stand a little soot—is that it’s also impossible to produce a yellow flame in a gas-fueled fire pit without producing some soot as a byproduct.
Why don’t all propane fire pits produce soot?
For those of you diggers, gearheads, and curious minds, let’s get into the science.
If you're wondering, “Don't most propane fire pits not leave behind soot?” you would be right. There are plenty of propane fire pits that don’t produce soot. in fact, with certain models of propane fire pits and fireplaces, the presence of soot can indicate an issue with the air mixer—such as not allowing enough oxygen to flow through and mix with the gas.
Your LavaBox, however, doesn’t come equipped with an air mixer. Again, worry not, this is by design.
Your favorite campfire in a can was meticulously designed around the principles of Reductive Design. (If you want to dig deeper into the design behind the box, read KISS: The Philosophy Behind the Best Portable Propane Fire Pit on Earth next.)
Throughout the initial phases of R&D (or call it obsessive garage tinkering), early LavaBox iterations saw various air mixer options installed and tested. This even included a few custom air mixers created by Josh, LavaBox’s creator and Chief Eruption Officer. But Josh had a bespoke vision in mind and through tons of trial and error, he came to find that even a custom air mixer didn’t cut it.
Including an air mixer meant adding more moving parts to the minimalist design. More moving parts equals more room for something to break down or falter. In the spirit of reductive design, the burner was moved upwards towards the lip of the ammo can. This allows ample air to flow through from the top of the box, reducing the amount of soot produced, and eliminating the need for an air mixer altogether.
All this trial and error took place with the goal to achieve an authentic, yellow flame—reminiscent of a traditional wood-burning campfire and massively tall if you want to crank up the heat. Air mixer be damned, we met that goal while staying true to the principles of reductive design.
This is what makes LavaBox so different from other portable propane fire pits
When you sit around a propane fire pit, you likely expect to see an icy blue flame that quickly dissipates into thin air.
This is because propane is a hydrocarbon (same as natural gas—propane is a byproduct of natural gas processing). Naturally, hydrocarbons produce a blue flame when burned due to the fact that they are some of the cleanest burning (lowest carbon-emitting) fuels available.
Conversely, we humans naturally possess a deep primal urge for the classic yellow/orange flame. Even if you can’t relate to your prehistoric ancestors, you likely equate the word “campfire” to gathering around a cozy yellow flame.
Reducing the amount of air that mixes with the propane fueling your LavaBox enables the nostalgic yellow campfire flame that warms both your hands and your soul.
A little bit of soot is the small price we pay for creating a fire ban compliant portable propane fire pit that actually looks and feels like a real wood-burning campfire.
That soot is the result of unburned carbon left behind due to the reduced oxygen-to-gas ratio (less oxygen, more gas). This process is known as a “rich burn”. Incorporating an air mixer can increase the amount of oxygen in the equation causing a “lean” (or cleaner) burn. But it also results in the thin blue flame you’d expect from most propane fire pits or gas stoves that you might gather around on a bar patio. . . But that’s highly disappointing to roast marshmallows over or warm up around before hopping into a cold tent for the night.
Does Unburned Carbon Cause a Safety Hazard?
The presence of soot alongside the use of some household gas appliances could indicate a safety hazard or malfunction. Particularly those that are meant to be used in an enclosed space.
Burning propane and natural gas produces carbon monoxide which replaces the oxygen in your lungs making it impossible to breathe. Gas appliances made for indoor use are equipped with safety features that mitigate the risk of excess carbon monoxide being released into the air.
For the sake of operating your LavaBox, there is no safety hazard presented because your LavaBox is never intended to be used inside your home or in an enclosed space such as a garage, van, or tent.
In short, as long as you’re in an open-air space (like your favorite campsite!), the “rich” burn and presence of soot do not pose any greater safety risk than any other propane-fueled fire pit presents.
If You REALLY Can’t Stand Soot, Stay Tuned!
While we can only try so hard to break the boundaries of science, we ARE working on a solution to the soot that our magnificent yellow flame elicits.
“We are now working on an adjustable air mixer that allows you to pick either a large yellow flame or something more like a stovetop burner.” - Josh Thurmond, Chief Eruption Officer