Kiln Dried or Seasoned Logs?

A common question we get asked, but first, what is the difference? Technically there is none because well-seasoned logs should be properly dried to below 25% moisture content. But in reality, when a customer buys ‘seasoned firewood’, it often has a much higher reading.

What does ‘kiln drying’ provide? Well, it should provide consistency, which means that every load you buy, whether it be in September, or February, will have a moisture content of 20% or below. Being consistently dry means it will light easily, burn cleanly and provide maximum heat output. By burning cleanly the stove glass should not go black and consequently the burn up the chimney or flue will be clean and not cause excess soot or tarring. Until you try kiln dried logs the difference cannot be truly appreciated and the most common response we get is “I couldn’t believe how much more heat it gave off”.

Some believe that by simply seasoning the wood, it is actually very difficult to achieve the same quality of log as kiln dried – probably true by the fact that generally people do not season the logs for long enough and are not drying them in the right way. Firstly, to properly season firewood, the wood must be cut into short log lengths, typically 25 cm, and then split down the middle to increase the surface area and aid the drying process. Log diameter should be typically 5-15 cm, and a range of sizes is perfect. The split logs need to be stacked under cover, with maximum airflow around the stack. How long the logs need to season will depend on the species. Ash, for example, might require 12-18 months whereas oak will probably need 3-4 years to get really dry and down to below 25% moisture.

Kiln drying is the process of force drying which can be done within anything from 60 hours to a week, depending on the type of drying process. Drying wood this way virtually sucks the moisture out of the log. One thing you will always find with kiln dried logs, unlike really well seasoned logs, is that there will be more of a gradient in moisture content across the log. Kiln dried logs usually show 10-15% on the outside and 20-25% on the inside, with the overall average below 20%.