We have some older firewood that’s burning too quickly. Because of this, we wanted to find out if our firewood is too dry. So, I did some research to find out more.
It’s unlikely for firewood to be too dry unless it’s 5+ years old or kiln-dried. Generally, overly dry firewood burns too fast and hot but still makes a great kindling. Firewood is considered to be too dry if it has under 10% moisture content, which can be tested by using a firewood moisture meter.
While it’s uncommon to have firewood that’s too dry, what are the cons of burning it, and what’s the best way to use it? Let’s take a look.
Want an easy way to check if your firewood is seasoned? I recommend using a firewood moisture meter. Here’s the moisture meter I use from Amazon.
The Problem With Firewood That’s Too Dry
The main issue with firewood that’s too dry (under 10% moisture content) is that it burns too fast and hot. Too fast of a fire and you’ll find yourself constantly adding more logs. Too hot of a fire is uncomfortable and potentially damages masonry such as chimneys.
If you find your fire is burning too hot (you’ll be able to feel it), simply hold off on adding wood and reduce the airflow. You can do this by slightly closing the damper to your fireplace or wood stove. Since fire needs oxygen to burn, cutting off some of the supply suppresses the fire to a manageable temperature.
However, if you’re using overly dry firewood in a fire pit or similar setup, some people like to soak the wood first. While some say that soaking firewood creates more work as the fire now needs more energy to boil the water out of the wood, others say it works to slow and cool the fire to a more sustained burn.
So, feel free to experiment with your dry firewood and see what works for you.
While hardwoods such as oak are known to burn longer, when they’re too dry they burn quicker—similar to softwoods such as pine.
How Dry Should Firewood Be?
The best firewood to burn has a moisture content between 15%-20%. This helps the fire burn cleaner, hotter, and longer. Any less than 10% and the wood is too dry. Over 20% and the wood is too fresh or “green”.
Green firewood is wood that has been freshly cut and hasn’t been seasoned (air-dried) yet. Other than being more difficult to light, the biggest problem with burning green firewood is that it produces significantly more smoke and creosote (the harmful tar buildup you see in chimneys).
Recommended: What is Seasoned Firewood? (Explained)
For example, most firewood takes at least 6-12 months to season. For the fastest seasoning, split firewood into quarters, store it in a dry place outside, and keep it off the ground.
Alternatively, commercial firewood is often seasoned with a kiln or oven. This firewood only takes about 2-3 days to dry. Most kiln-dried firewood is between 15%-20% moisture, but some may be drier.
Generally, the rule is if the firewood isn’t rotten, it’s okay to burn. I would add to avoid burning treated wood as it releases contaminants when burned.
Properly seasoned firewood also helps prevent termites from infesting the firewood.
How Firewood Dries
| Air-Dried | Kiln-Dried |
|---|---|
| 6-12 months to season | 2-3 days to season |
| Anyone can do | Commercial |
| Free | More Expensive |
When seasoning, firewood has two stages of water loss.
Free water is water that is found in the wood cavities and is easily lost. This is the first water to leave green wood and gets the moisture content down to around 30%. Free water leaves the wood similar to a wick.
Bound water is the water held within the wood’s cell walls and takes much longer to dry. The loss of bound water is what gets the firewood below a 30% moisture content and makes it suitable to burn. Much of the bound water is found deeper in the wood, which is why splitting firewood is helpful.
Once firewood is seasoned and loses its bound water, it cannot become unseasoned. For example, seasoned firewood that gets wet (such as if it’s rained on) is free water, and dries within about 1-2 sunny days.
So, if you’re soaking your overly dry firewood to make it burn longer, know that you’re adding free water, and you’re not undoing any seasoning that’s already occurred.
How to Measure Firewood Moisture
The most accurate way to measure a firewood’s moisture content is to use a firewood moisture meter. Use it to test several logs and get a good average percentage. If your firewood is above 20%, it needs to season longer. If it’s between 15%-20% it’s perfect to use as firewood.
If you’d like my recommendation, I use this moisture meter from Amazon.
There are a few other ways to tell if firewood is seasoned or not.
- Visual – Seasoned firewood has cracks forming and is much lighter in weight (due to the loss of water). After holding both unseasoned and seasoned firewood, you’ll be able to remember the difference in weight.
- Sound – When two pieces of seasoned firewood are hit together, it makes a ringing sound. Unseasoned firewood makes a dull thud sound as the water in the wood absorbs more of the sound.
What to Do If Your Firewood Is Too Dry
If your firewood is under 10% moisture content and is too dry, it’s still fine to burn. It just may get too hot or burn too fast for your liking. However, since it’s drier and easier to light, you can also set it aside for kindling. It can also be used in fire pits.
If you can’t find a use for it, dry and old firewood makes great compost.
Last year, we used some old firewood logs as Hugulkultur for our garden’s raised beds. By burying the logs under the soil, they slowly rotted, providing the plants with plenty of nutrients and moisture. We had some of the best tomato yields that year!
Also, consider mixing your dry firewood with some of your newer firewood to balance out the burn. For example, mix some firewood that has 10% moisture with firewood closer to 20%. Remember, only burn firewood that’s under 20% to avoid excess smoke and creosote.
Final Thoughts
It’s almost impossible to have firewood that’s too dry. Because of this, it’s typically best not to worry about it. However, if you believe your firewood is burning too fast/hot, test it with a firewood moisture meter and check that it’s between 15%-20%.
If you happen to have firewood with less than 10% moisture content, and you’re using it in a fireplace or wood stove, consider closing the damper slightly to reduce airflow and limit the fire’s heat.
For fire pits and the like, either soak the firewood or mix it with less dry wood (but still under 20% moisture content).
Worst case, use the wood as compost for your garden or simply toss it. Although, I’m sure you’ll find a use for it between kindling and the like.
The main thing to keep in mind is not to burn rotting firewood. As long as you keep your firewood in a dry place and off of the ground, it won’t rot anytime soon.
Sources
Need More Help?
You can always ask us here at Fireplace Tips, but you should know the other resources available to you! Here are the resources we recommend.
- Chimney Safety Institute of North America (CSIA): The CSIA is your BEST resource for fireplace and chimney safety at home. They’re a non-profit governed by a volunteer board of directors dedicated to the education, training, and certification of chimney and industry related professionals.
- Self-Sufficiency and Off-Grid: If you’re like me and passionate about off-grid and self-sufficiency, see my number 1 resource—Abundance Plus. Check out their Frugal Homesteading Course on growing 90% of your own food. Get 7-days free and 10% off with the code: TYLER10