Firewood Production Process
Firewood is made of locally supplied timber. The wood species we use to make firewood are: beech, Ash, Oak, Birch, Alder, Pine and Fir. Each log can be cut into pieces of 25, 30 or 45 cm, split 4-6 times for 8-15 cm diameter and stacked into 1m³, 1,8m³, 2m³ or 2,2m³ boxes or bags of 9.5 L, 21 L, 30 L, 40 L or 60 Liters.
It is sold in 3 levels of moisture: fresh (35-55%), air-dried (25-35%) or kiln-dried (<25%).
For natural air-drying we use the yard next-to warehouse. The boxes are kept with clearance of 30 cm to ensure 360° air ventilation and quick moisture release. During the storage, each box is covered with top to protect from direct rainfall.
For kiln drying we have drying chambers from the near-by constructional timber producers. The normal drying cycle in the kiln is 100 to 150 hours. The temperature maintained is 60° C. After the drying, the firewood is kept outside to ventilate excess vapor for minimally one day. For the moisture limit in the kiln-dried firewood, the Formula of Average Firewood Humidity is used. We take Moisture levels at:
• Outside End of log
• Inside End of log
• Inside Center of log
Then divide the sum by 3 and that is the Average Moisture of Firewood. The standard normal log has 15-20% outside moisture and ~30% in the very center inside of log.
For summer season we recommend to stock-in with Fresh firewood. This way, you will save money, because wood timber prices are cheapest in spring. Also in 3 to 4 months the firewood gets dried naturally, so minimal or none chamber-drying is required any more. So, the drying cost is saved as well.
Firewood Quality management
The most important for it are obviously the box quality and residual moisture (if it is dried). Ideal firewood box has strong side boards and well attached straps to endure the transfer and loading works.
The side boards must be ~5 cm width and correct rectangular shape. The 3 sides of the box are closed, the frontal part open for convenient access of logs. The box should have at least 2 straps around between top and bottom. The logs must be split at least into half, mostly in 4 or 6 pieces diagonally. The box shall contain only the wood logs (no timber remaining or waste wood). Logs have to be mold-free.
The moisture of its measurement rule: because there is no way to dry the whole log equally, one must refer to the average of the moisture level. The applied rule is fully quoted below.
humidity measurement method: an average size firewood log (from center of box) shall be split and left for 30 min indoor to evaporate. Then 3 measures shall be taken: a) center of outer side of log, b) end of log, b) center of split log inner side. The average of 3 measures is the humidity content. Dry firewood is considered to be of no more than 25% humidity content, unless agreed other. No limits apply for fresh humidity content.”
Warehousing : The key steps, to avoid problems with firewood, are: 1. Protect from moisture absorption, 2. Protect from direct rain and 3. Protect from mold formation in poor ventilation. The best place to keep the firewood is outside in the open wind under cover/roof. This way it gets good ventilation and there’s no potential for mold to grow. Other option is in a warehouse if one can make sure the firewood gets sufficient 360° ventilation.
When the fresh wood is stored outside, it would dry faster if there’s direct sunlight. In such case we recommend to cover the boxes with the plastic transparent tops to protect from rain.
Thanks to its good burning features and pleasant odor, it is most appreciated in Norway, Malta and in number of other countries as well. Birch is not only valuable heating fuel, but also perfect to use in private and business for Pizza Ovens, Steak Grill etc., picnics, camping, Sauna and so forth. For dry birch firewood, packed in bags