A wood is considered "seasoned" if has a moisture content of 20 to 25 percent. Burning unseasoned wood in your wood stove causes creosote residue because more energy is used to remove the excess water in the wood. While the water burns off, cooler smoke enters the flue, which can cause creosote build up. Unseasoned logs that are fully packed will also release more cold air, as they are specifically designed to burn for eight to 10 hours at a cooler temperature. When picking out wood for your stove, you should avoid extra-dry or well-seasoned logs, as these can cause creosote build up as well.
Softwoods are more likely than hardwoods to cause creosote build up in your wood stove flue. However, when you are picking out a hardwood variety, the Chimney Safety Institute of America warns that only seasoned hardwoods should be used, as the moisture content is more important than the density of the wood. Examples of seasoned hardwoods include oak, hickory and pine, which burn overnight; and aspen, which creates a hotter fire.
To season your wood stove's hardwood fuel at home, the Encyclopedia of Alternative Energy and Sustainable Living recommends splitting your logs in two, storing them in a dry environment and piling the wood loosely to promote air circulation. Depending on the humidity and temperature, your logs' drying time will vary from six to 18 months. When the logs are fully seasoned, they will have an even coloring and no remaining greenish-colored spots.
Creosote build up occurs when flue temperatures drop below 250 degrees Fahrenheit. To prevent creosote build up in your wood stove's flue, the Chimney Safety Institute of America recommends inspecting your flue regularly and installing a temperature gauge to detect low fire temperatures. Only wood should be burned in your wood stove and never materials such as wrapping paper, cardboard boxes or trash. Finally, always keep a fire extinguisher nearby in case of a creosote-related fire.