Wood fires are an inexpensive, environmentally-friendly way to cook food and stay warm. Whether for a barbecue, campfire, or fireplace, you want wood that burns effectively and is safe to use. But did you know that all firewood is not equal?
Firewood can be too wet or too dry. (Yes, there is such a thing!) The firewood you want to use or buy should be perfectly ‘seasoned.’
For firewood to be thoroughly dry, but not too dry, it must be dried in an area that is moisture free for about 6 months. This process is also referred to as seasoning firewood.
What Is ‘Seasoned’ Wood?
The green wood of living trees contains a lot of moisture. Wet wood makes poor firewood. It won’t burn properly or give off enough heat. You want to be sure seasoned wood to get the most out of your firewood. ‘Seasoning’ refers to the process of drying out firewood over time. This helps to lower the moisture content of the wood.
What Moisture Level Is Acceptable in Firewood?
Properly seasoned wood has a moisture content below 20%. The right band of moisture lies between 15 and 20%. Anything over 20% will cause issues, such as sluggish ignition and flames that keep extinguishing.
But the problem escalates as the moisture level increases beyond 30%. It can become very hard for firewood to burn at all. As the wood heats up, water bubbles from at the end grain. This is a common issue in Poplar and Aspen trees. They have a high native moisture content, making them non-combustible when unseasoned.
How Long Does the Seasoning Process Take?
Seasoning is a lengthy process that can take months, or even years, to complete. Typically, it takes about six months. So wood harvested in the spring dries throughout the summer and is ready for use by fall. But the time varies from species to species.
While time is a critical factor of seasoning, it is not the only one. It also depends on the type of wood, the starting moisture content, and the wood’s exposure to weather.
For instance, split, stacked wood exposed to drying breezes will season faster than unsplit logs laying on the ground. Similarly, in a large pile of firewood, pieces in the center will take longer to dry out than those near the edges
The easiest way to store your firewood is with a firewood log rack like this one by Woodhaven. Its structural integrity is very sound, and will keep your firewood off of the ground. It also comes with its own cover that will cover the top 12″ of your firewood.
Why Its Essential for Firewood to Be Dry
Newly cut wood has a fair amount of water in it. The moisture content is far more than the recommended amount for firewood. It will burn very ineffectively. It would struggle to catch alight and would struggle to continue burning in the fire.
The higher the moisture content in a piece of wood, the longer it takes to break down when burned. It not only burns considerably slower, but it also produces less heat than a dry piece of wood of the same size. That is because the heat energy is initially used to boil the extra moisture out of the wood.
Furthermore, freshly cut wood produces more smoke than usual firewood. The incomplete combustion of wet wood produces dirtier smoke. This may accumulate as creosote in your chimney. If the level of creosote builds up, it may ignite, creating a chimney fire.
On the other hand, dry firewood produces more heat. Since there is less moisture content, the firewood requires less heat to evaporate the water. Moreover, dry wood burns more completely, creating a cleaner and safer fire.
It’s pretty clear that the drier the firewood, the quicker it breaks down. Properly seasoned firewood is ideal. This is when 15 to 20% of its weight is water. The water in the firewood helps to regulate the combustion process.
How Do I Know if My Wood Is Dry Enough to Burn?
The ‘time since a tree was cut’ isn’t a reliable indicator of how dry your wood is. Some species take longer than others.
So it can be challenging to know if your firewood is dry enough to burn. However, there are several techniques you can use to judge whether you have seasoned firewood.
Some of them are:
Weight
Dry firewood is often lighter than green wood. But sometimes, this can be misleading. The natural density of wood can vary significantly between different species. This can make it difficult to use weight as a determining factor.
Sound
Dry wood produces a hollow sound when struck against another piece. Conversely, wet wood makes a dull thud when struck.
Appearance
Dry firewood usually has ‘drying checks’ or cracks on the ends of the logs. The bark comes away or easily peels off.
Color
Dry firewood is darker brown with little or no hint of green.
Use a moisture meter
The most accurate method of verifying whether a piece of wood is properly seasoned is to use a moisture meter. Insert the instrument into the wood to check the moisture content of the lumber. Anything between 15 and 20% is acceptable.
What Happens When You Have Really Dry Wood?
Firewood which gets seasoned for longer, loses much of the water that regulates the combustion process. Since the wood is over dry, it produces a fire that is hard to control. The fire is too hot and burns too fast.
For a barbeque or outdoor pit, it merely means you will end up using more firewood. But if you use this kind of wood in a wood stove, it can produce an intense fire.
The inferno may howl in the furnace, which is sure to make everyone in your house nervous. But fires this intense can do some serious damage to the inside of your stove.
What Should I Do With Firewood That Is Too Dry?
If you happen to have some very dry firewood, mix it with regular firewood to raise the full load’s moisture content. This is a much better alternative than just burning the wood by itself or throwing it out altogether.
Final Thoughts
Good firewood is low in moisture content. Fully seasoned firewood should have a moisture content below 20%.
Properly seasoned firewood can take about 6 months to fully dry as long as it is kept in an area that is dry and absent of moisture.
If you buy firewood, split, stack, and store it above the ground to ensure it remains in good condition.