Smoke is a byproduct that’s created when organic matter, including wood, burns. Whether you use a fireplace, a fire pit, a stove or a chiminea, it will probably produce smoke. As a result, many people assume that it’s normal for wood-burning fires to produce lots of smoke. The reality, however, is that excess smoke is indicative of an incomplete combustion process, and if left unchecked, it could lead to several problems.

Why Wood-Burning Fires Produce Smoke

Wood-burning fires produce smoke when the wood doesn’t burn completely. To the naked eye, smoke may look like nothing more than gases or vapors. If you observe it under a microscope, though, you’ll discover that it contains many small pieces of organic matter. Also known as particulate matter, these ultra-fine particles are released into the air when wood doesn’t burn completely.

All fires involve the combustion of organic matter, and wood-burning fires are no exception. If the wood doesn’t burn completely — meaning the combustion process is incomplete — it will release smoke as a byproduct. Smoke contains fine wood particles that float up and into the air.

The Dangers of Smoke

While a little smoke is typically harmless, excess smoke poses several concerns. According to the U.S. Environmental Protection Agency (EPA), exposure to smoke can cause upper respiratory irritation. When smoke gets into your nose and mouth, it will inadvertently enter your lungs where it causes irritation. People who suffer from asthma are especially at risk for upper respiratory irritation caused by smoke exposure. If you suffer from asthma and are exposed to excess smoke, it may trigger an asthma attack.

Smoke is also responsible for creosote buildup in chimneys. If your home has a fireplace, excess smoke may cause creosote to accumulate inside the chimney flue. As the smoke rises up into the flue, it will stick to the flue’s interior walls. Over time, the flue may become clogged with creosote to the point where it restricts air from entering and leaving through the top of the chimney. What’s even more concerning, however, is the potential for a house fire. Creosote is a highly flammable substance that can ignite and trigger an explosion. If the creosote inside your fireplace flue heats up enough, it may ignite or explode.

Choose Dry Firewood

To minimize the amount of smoke your wood-burning fires produce, only use dry firewood. All wood contains moisture, but the amount of moisture they contain varies depending on how the wood was processed. Wood that’s harvested from a free and immediately sold typically has a high moisture content. Known as fresh firewood or green firewood, it may have a moisture content of 100% or higher. At 100%, half of the wood’s weight is in water. All that moisture prevents the wood from burning completely. Some of the “wet” wood will burn, but much of its organic matter will be released in the form of smoke.

Some firewood is processed outdoors to lower its moisture content. Known as air-dried firewood, it has an average moisture content of about 20% to 25%. Even air-dried firewood, however, can produce smoke.

Don’t just fresh, green or even air-dried wood. Instead, choose kiln dried wood to prevent excess smoke. Kiln dried wood is characterized by an advancing processing method. In terms of performance, it’s superior to all other types of wood. Kiln dried firewood is processed in a drying kiln that extracts moisture from its pores. Kiln dried firewood often has a moisture content of just 10% to 15%, making it several times drier than fresh firewood and green firewood. The exceptionally dry properties of kiln dried firewood means it produces little to no smoke when burned.

Choose Hardwood Firewood

In addition to being dry, you should choose hardwood firewood. Hardwood varieties, such as oak, are denser than softwood varieties. The density of wood, of course, refers to the amount of organic matter it contains. With more organic matter, hardwood varieties contain more fuel than their softwood counterparts. Therefore, they are able to burn brighter and hotter to create a more complete combustion process.

Hardwood firewood isn’t just denser than softwood firewood; it contains less sap. Why does this matter? Like moisture, sap restricts the combustion process. It prevents the wood from burning completely while causing it to produce more smoke as a result. Hardwood trees don’t produce sap, however. They still produce resin, but they don’t produce any sap. Therefore, hardwood firewood burns more completely than softwood firewood to achieve greater heat and less smoke. By sticking with kiln dried firewood of a hardwood variety, you can rest assured knowing that you won’t get smoked out.

Common types of hardwood firewood include the following:

  • Oak
  • Hickory
  • Maple
  • Ash
  • Cherry

Increase Airflow

Another way to prevent excess smoke with a wood-burning fire is to increase airflow. Starving or otherwise restricting your fire of fresh air will cause its temperature to drop. All fires need both organic matter and oxygen to burn. Without either of these elements, they’ll burn out.

So, how do you increase airflow in a wood-burning fire? It really depends on the type of device in which you build a fire. If you’re building a fire in a fireplace, you can increase airflow by opening the flue damper all the way. If the damper is only partially open, less air will be able to enter and leave the fireplace, thereby starving your fire of fresh air. If you’re building a fire in a fire pit, on the other hand, you should position the fire pit in an area where it’s exposed to the wind. With greater airflow, your fire will burn brighter and hotter, resulting in less smoke.

Add More Wood

The amount of wood you burn in a fire will affect the amount of smoke it produces. Generally speaking, smaller fires produce more smoke than larger fires. If you only use two or three small logs to build a fire, for instance, you can expect a significant amount of smoke. With only a few small logs, the fire will burn at a lower temperature, which may prevent some of the organic matter from burning completely.

To prevent your home or outdoor living space from being smoked out, build large fires using lots of dry, hardwood firewood. Your fires will burn brighter and hotter if you build them using lots of firewood. You should also keep your fires going by adding more wood when needed. If the fire is dying down, toss a few new pieces of kiln-dried firewood into it.

The bottom line is that it’s not normal for a wood-burning fire to produce a lot of smoke. Excess smoke is a sign of incomplete combustion. If the wood doesn’t burn completely, it will release airborne particulate matter in the form of smoke. You can reduce the amount of smoke produced by your wood-burning fires, however, by following these tips.

Experience the difference kiln dried firewood makes in your fires by visiting our online store today. Cutting Edge Firewood is the Southeast’s premier vendor of high-quality kiln-dried firewood. We offer a variety of the industry’s finest firewood, including oak, hickory, cherry and more.