One of the questions we get asked a lot is ‘why should I use kiln-dried logs over seasoned logs?’
It’s true that kiln-dried logs are usually more expensive, so it can be tempting to opt for cheaper seasoned logs. However, choosing seasoned logs may be a false economy! Let’s explore why kiln-dried logs are the better option for your log burner.
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Why do logs need to be dried?
Time for a science lesson!
Wood is hygroscopic, meaning it gains and loses moisture to the air naturally. When logs are cut, they will contain a lot of water, sometimes more than 60%
It's really important that wood is dried to less than 20% moisture content before it's burned for a few reasons.
When wet wood is burned, a significant portion of the initial energy is used to evaporate the water from the wood, which makes it much harder to light your fire, and results in less heat output once it is lit.
Wet wood also emits significantly more smoke and particulate matter than drier wood, which is bad for your log burner and even worse for your health!
In contrast, kiln-dried logs light more easily and burn hotter, making them a much more efficient choice. They also produce significantly less smoke and particulate matter, which is better for your health and for the longevity of your log burner.
What is seasoning?
Seasoned logs are dried naturally over a period of time. This means they're stacked in a way that allows air to flow through so that the moisture from inside the wood evaporates.
Depending on the species of wood and the conditions in which they're kept, seasoned logs can take anywhere from 6 months to 2 years to properly dry.
They need to be kept in a place with low humidity, off the floor, away from walls and obviously, out of the rain!
This is a key reason why kiln-dried logs are often preferable —they offer a much quicker and more reliable drying process.
What is kiln-drying?
Kiln-drying means drying the logs in a chamber, or kiln, where the temperature, air circulation and humidity are controlled.
What are the benefits of kiln-drying firewood?
The benefits of kiln-dried wood over seasoned wood are the consistency of quality, reduced emissions, cleaner burning and reliability of availability
1. Consistent Quality
One reason to use kiln-dried logs is that kiln drying is a controlled process that ensures consistency in the quality of the logs.
We know exactly how long each species of wood will take to dry in the controlled temperature and conditions of the kiln, so we can guarantee that the moisture levels of kiln-dried logs are consistently below 20%.
It's much harder to predict how long it will take to fully season a batch of logs to below 20% moisture content. The time taken to season firewood depends on where and how it has been stored, and what the weather conditions have been over that time period. This can result in some seasoned logs being sold before they have reached 20% moisture, which gives a bad burning experience. This is much less likely with kiln-dried logs.
2. Reduced Emissions
When wood is burned, it emits particulate matter. Some of this particulate matter we can see, like smoke, and some is microscopic but we can breathe it all in and it can be harmful to human health.
The drier the wood, the less particulate matter it emits. In fact, wood dried to below 20% moisture has been found to release less than half the levels of particulate matter when compared to wet wood.
Burning kiln-dried firewood means your logs will have a consistently low moisture content and therefore release less particulate matter. This makes kiln-dried logs a much cleaner option, both for your home environment and the air quality in general.
3. A better burning experience
Due to the more consistent moisture levels in kiln-dried logs, they tend to be easier to light and burn hotter and for longer than seasoned logs.
4. Reliable availability
As seasoned logs can take anywhere from 6 months to 2 years to fully season, the firewood available at the start of the winter is the only firewood that will be available for the whole of that winter. During especially busy or cold winters, it's common for companies selling seasoned firewood to run out before the season is over.
As the kiln-drying process only takes a few days, more kiln-dried logs can be dried constantly throughout the winter so the supply of kiln-dried logs is much more reliable.
Why should I use kiln-dried logs?
You should use kiln-dried logs because they are reliably easy to light, burn hot and clean, with very little smoke and soot, and you know you can re-stock whenever you run out!
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