What Is Creosote?
Creosote is a tar like substance that can build up in a chimney. When wood or coal is burned slowly, it produces tar and other organic vapors which combine with expelled moisture to form creosote. The creosote vapors condense in the relatively cool chimney flue of a slow-burning fire. As a result, creosote residue accumulates on the flue lining. If ignited, this creosote creates an extremely hot fire which may ignite surrounding materials resulting in a building fire. The chimney connector and chimney should be inspected at least twice a month during the heating season to determine if a creosote buildup has occurred.
Much like warm air forms condensation when it interacts with a cool surface (imagine an ice filled glass on a warm day), smoke condenses when it cools down as well. The difference is that in addition to water vapor, smoke condensation (a.k.a. creosote) contains tar and soot and causes chimney fires if not cleaned out on a regular basis. Creosote builds up more quickly when you burn small, cool fires, use unseasoned wood or have a wood burning insert installed without a properly sized flue. To avoid excessive creosote build up it is recommended that you burn only well seasoned hardwood, burn hot fires, don’t make a habit of burning small fires, have your chimney inspected at least once per year or more often if you use your stove as your primary heating source.
Creosote is the name used for a variety of products: wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles. These products are mixtures of many chemicals created by high-temperature treatment of beech and other woods, coal, or from the resin of the creosote bush. Wood creosote is a colorless to yellowish greasy liquid with a smoky odor and burned taste. Coal tar creosote is a thick, oily liquid that is typically amber to black in color. Coal tar and coal tar pitch are usually thick, black, or dark-brown liquids or semisolids with a smoky odor. Wood creosote has been used as a disinfectant, a laxative, and a cough treatment, but is rarely used these ways today. Coal tar products are used in medicines to treat skin diseases such as psoriasis, and are also used as animal and bird repellents, insecticides, restricted pesticides, animal dips, and fungicides. Coal tar creosote is the most widely used wood preservative in the United States. Coal tar, coal ta
