If you have ever lived in a home with wood stove or fireplace, you might have noticed that sometimes bits of debris have fallen from the flue into your fireplace or stove. That shows you have a creosote buildup on the inside of your chimney flue.

Creosote is a black or brown residue that sticks to the inner walls of your chimney or stove pipes. In texture, it can appear crusty or flaky, drippy and sticky like tar, or shiny and hardened to the surface. But whatever its appearance, creosote is highly combustible. And it creates a serious fire risk.

Certain conditions that can cause creosote buildup include:

1. Cool flue temperatures. When the temperature inside your flue is cooler than normal, smoke will condense, causing creosote form on the inner walls at an accelerated rate. Metal chimneys are very susceptible to creosote buildup. Their light sheet metal construction helps to keep the interior flue temperature abnormally cool. Also the location of the chimney can affect the interior temperature. A chimney on an exterior wall can be affected by outside cooler temperatures while a chimney located on an interior wall is usually warmer.
2. An oversized flue. If your home has an older fireplace insert or a hearth-mounted stove that’s vented into a masonry chimney, chances are, your flue is too large to support the fireplace insert or stove. So the smoke from a fire can hang around in the chimney for a longer time (called residence time), leading to creosote buildup.
3. Restricted air flow. Not only does an oversized flue confine air supply in a chimney, but closing the glass doors on a fireplace or stove too tightly, or failing to open the chimney’s dampers wide enough can hamper the amount of air flow in your chimney. In these conditions, the restricted air flow prevents the smoke from leaving and increases its residence time. Again, enabling creosote buildup.
4. Use of unseasoned firewood. Firewood that’s unseasoned or dried insufficiently contains water. When unseasoned firewood is burned, it creates less heat because most of the fire’s energy is used to burn away the moisture. Since the fire is cooler, the smoke condenses quickly, forming creosote on the flue’s surface.

For the EGAN camping wood stove the chimney pipes are made of stainless steel with no paint or any coating that can be melted by heating. Therefore, what we see in this photo is the creosote buildup in the chimney pipe. The main reasons for the creosote buildup are:

• Using wet wood as the fuel
• Using wood pieces that have coating or paint as the fuel
• Clogged chimney pipe

In order to prevent the creosote buildup in the chimney pipe, you should simply follow the safety instructions. On the first page of the safety instructions that comes with the EGAN package, you can see this:

• While you are installing the stove, you should inspect everything before using the stove. The chimney pipes should be inspected for any possible blockage.

• Do not use wet wood as a fuel for this camping stove. If you use wet wood as fuel in the stove, it will make a cold fire with a lot of water vapor. It makes excessive smoke and the water vapor will condense on the inside surface of the upper pieces of the chimney pipe and flows downward as you see in the photo here. This is a general phenomenon and it can happen to any wood stove. For the EGAN camping wood stove, the only fuel is dry natural wood. That's why we mentioned it as a caution and warning on the front page and also in page 4 of the safety instructions.

• Use the chimney pipe connectors/adapters to install the chimney pipes so that the male side of all the pipe pieces point downward. This ensure that in case of creosote buildup in the chimney pipe, it will flow downward to the fire box and will not leak from the chimney pipe connection points.