September 2010 – Page 3 – Ask the Chimney Sweep

If you are up to the task of burning wood, you'll want to know which types of wood are best to burn and which you should avoid. There isn't a miracle wood that is the best breed of tree to burn. The real key to having a fire producing maximum heat and minimal creosote buildup is making sure that the wood is really and truly seasoned. Truly seasoned wood is not the wood you cut this year, it is the wood you cut last year. Oak, for example, takes a whole year to season thoroughly. Newly cut, wet wood will smolder rather than burn completely. It can be frustrating and disappointing if you are trying to make a fire using wood that has not had a chance to dry itself of the moisture naturally found in it because the heat that you are hoping will radiate into your home is being spent evaporating this moisture. The moisture in these wet logs will actually aid in creosote buildup because the added water vapor being vented up the chimney will cause other gases to condense on the walls of the flue system and buildup. Burning seasoned wood is essential to having a fire that is the most efficient for your money, you do not want to spend hundreds of dollars on firewood for a season just for it to burn poorly. Keeping your firewood on a log rack to season as opposed to laying it on the ground and covering the top half of it with a tarp helps dry wood faster. So how do you know if what you are looking at is truly seasoned? The salesman can tell you it was chopped however long ago, but you should inspect the wood for signs of truly being seasoned prior to purchasing. Wood that is truly seasoned looks darker and grayer than new wood. Similarly, the inside of a seasoned log is actually close to a white color which is not true of freshly cut wood.Seasoned wood will have bark that is easy to detach, cracks running up the log, and small cracks on the inner rings of the tree if you look closely enough. Newly cut wood has bark which is firmly attached to it and a fresher looking center than the outside ring. This outside ring will be drier and obviously more dried out than the inner ring which takes a long time to season properly. If you cut your own wood and are waiting for it to season on its own it is important not to put a tarp over the wood. The tarp will trap in moisture that is trying to dry out from the wood naturally. Instead get a log rack that will allow air flow all around the logs. Now comes the discussion of whether or not to choose a hardwood or a softwood, and the truth is is that there are pros and cons to each. Read carefully and decide what exactly you are looking to get out of your wood this winter. Contrary to popular belief, dry, seasoned softwood actually contributed less creosote buildup than seasoned hardwood. This is due to the fact that dry softwoods burn hotter and more rapidly than hardwoods because they are less dense, and the more intense flame causes the products of combustion to move more quickly up through the chimney. When looking down a flue system, this is what swollen creosote looks like. Seasoned hardwood is what we recommend. This being said, you get more for your money when you are buying hardwood. Hardwoods like walnut cost more per cord than softwoods such as pine or fir but because the hardwood is more dense you are actually getting more woodper cord. Hardwoods burn longer than softwoods, so you have to feed the fire far less frequently when you are burning hardwood than when you are burning softwood. Because of this fact you get nearly twice the fire when purchasing hardwood as opposed to softwood. Softwood, however, is more easily lit and better for first time fireplace users and the like because getting a nice burn with a hardwood takes practice and patience. If you do decide that hardwood is the way to go you must be sure to have plenty of kindling. A nice, dry softwood is great kindling for a hardwood. If you are just a beginner at fireplace fire building, I would recommend to you fir. This wood, when dry, burns very hot and has a welcoming aroma. If you get well seasoned fir wood you will have to feed the fire a bit more than if you were using hardwood but your chances of success at building each fire are much higher.