We hear this question all the time, but do you know the difference? You’d assume that there isn’t one, because surely both should be suitably seasoned to a moisture content below 25%. However, the reality is, due to a number of varying factors, that seasoned firewood will usually have a much higher reading than its kiln dried counterpart.
How many times in the past have you been promised well-seasoned logs? Only to find that they struggle to burn when you get home. Then stove glass begins to blacken and all of a sudden you’re smoked out of living room? Well therein lies the problem – those logs were never properly dried.
So how does kiln drying solve this? Well the proof should be in the pudding, each log load should be consistent – month to month, season to season, each log being dry and easy to light. They should provide the maximum heat output when burning, the stove glass should remain clear, the chimney and flue – free of excess soot and tar. Only once you’ve tried it for yourself, will you see and feel the difference. We’re convinced you’ll notice how much more heat is generated using kiln dried logs, on your very first log load.
But all is not lost with seasoned wood. If seasoned properly and for long enough, in the right conditions – then you can achieve a product of a similar quality to kiln dried. However, most people just don’t do it correctly. They don’t understand the drying process; the logs need to be cut into short lengths (approximately 25cm) and split down the center to provide a greater drying surface. Logs then need to be stacked and covered, allowing for the maximum amount of air to circulate around each stack.
How long you leave the logs to season is down to what type of wood is used. This is where your supplier needs to know their stuff! Ash might only take 12-18 months to reach the right moisture content. However, hardier species such as Oak could require 3-4 years to meet the mark and ensure the core has fully dried out.
This is why the kiln-drying process wins with firewood producers, as the time required to create a fully seasoned product, is massively reduced. Anywhere from 60 hours to a week, depending on the species and drying process used, is a big improvement on 18 months to 4 years.
How can it create the same if not better results in a quicker timeframe? Well, it’s simple – kiln drying literally dehydrates the wood, sucking out the moisture right to the core. However, unlike seasoned logs, kiln dried logs will be much drier on the outside. Producing a typical moisture level of around 10-15% with the core at 20-25% – giving a average reading for the log as whole at under 20%.
As a result, the kiln dried logs produce a much more consistent moisture level throughout the entire load.