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What Is Creosote and How Can You Keep It From Forming?

Your fireplace or wood-burning stove can be an excellent source of heat and relaxation. However, your fireplace and chimney can also prove a safety hazard if you do not care for them properly and take certain precautions when burning wood.
One of the biggest concerns, in terms of chimney safety, is creosote buildup. Keep reading to learn more about creosote, the risks it presents, and how to prevent it from forming.
What Is Creosote?
Creosote is a sticky, black substance that distills from wood when it burns at around 500 degrees F. The creosote begins on a vapor; it may then condense on the walls of your chimney.
In its early stages, creosote buildup appears like an ashy soot. If the buildup continues, the creosote begins looking more like shiny, black cornflakes. In the most advanced stage of buildup, creosote on chimney walls looks like black tar. 
Creosote forms when your fire is not burning hot enough. If the fire reaches 1100 degrees F, the creosote vapors will burn away. At cooler temperatures, the creosote will continue up the chimney, and if the chimney walls are cool enough, the creosote will condense and cling to the walls.
Why Is Creosote So Dangerous?
Creosote buildup in your chimney can cause two major problems.
First, it may create an obstruction in the chimney, preventing smoke from exiting the house as you should. Smoke, and the dangerous carbon monoxide it contains, may build up in your home instead.
Second, creosote is also flammable. Creosote buildup on your chimney walls may catch fire, leading to a destructive chimney fire.
Creosote presents a hazard to your health. Long-term exposure may increase your risk of certain cancers. If the creosote buildup is isolated to your chimney, you probably won't experience too much exposure - but still, you're better off safe than sorry. 
How Do You Create Creosote Buildup?
To prevent creosote from forming in your chimney, you basically want to avoid the following three practices that can cause your fire to burn too cool.
1. Burning Green Wood
Wood needs to be properly seasoned, or aged, in order to burn hot and prevent creosote buildup. Generally, proper seasoning takes between six months and two years. Here are some signs that your wood is adequately aged: 
  • Its color has faded; it's more gray than brown.
  • It has become lighter in weight and harder in texture.
  • The bark is loose and easy to remove.
  • It produces a hollow sound when struck.
  • It has a light, woody smell rather than a fresh, sappy aroma.
If your wood is taking a long time to catch fire or is producing a lot of smoke when burning, it is probably still too green to burn safely.
2. Overloading the Fire Box
You may be tempted to over-stuff the fire box so you don't need to stoke the fire as often. However, this practice can change the temperature of your fire to an unsafe level. Don't fill your firebox too full, and simply add logs more often to keep your fire burning strong.
3. Using an Improper Flue and Chimney Liner
Chimney temperature also plays a role in creosote deposition. If the chimney is too cool, creosote is more likely to form. An improperly sized flue, damaged chimney liner, or lack of chimney insulation can all lead to a too-cool chimney.
Prevent issues with your flue and liner by having your fireplace setup inspected by a knowledgeable professional. They may recommend a few changes, like a new flue or liner, to reduce your risk of creosote formation.
Creosote buildup presents more than a minor annoyance for homeowners with fireplaces. Follow the tips above, and make sure your family is safe by scheduling an inspection with R & R Fireplace and Chimney