Quick Answer
To measure the moisture content of firewood, use a high-accuracy hygrometer, a moisture meter specifically designed for wood, or a more primitive method like the "split test": split a wood sample and observe the time it takes for the inner wood to dry to the surface.
Choosing the Right Moisture Meter
When selecting a moisture meter, look for one with an accuracy of ±1% relative humidity (RH). A good moisture meter should be specifically designed for wood, with a penetration depth of at least 1 inch (2.5 cm) to accurately measure the moisture content of dry firewood. Popular options include the LignoMeter, the Wood-Wide Web Moisture Meter, and the Extech MO290.
The Split Test Method
For those without access to a high-tech moisture meter, the split test method can provide a rough estimate of moisture content. Cut a small sample of firewood in half lengthwise, exposing the inner wood. If the inner wood is dry and turns dark brown or black within a few hours, the firewood is likely dry (less than 20% MC). If the inner wood takes longer to dry or remains green, the firewood is still too moist.
Stacking Firewood to Control Moisture
Proper stacking techniques can also help control moisture content in firewood. Stack firewood in a way that allows for airflow and sun exposure. Leave space between the stacks to allow for air circulation. Covering the top of the pile with a breathable material like burlap or a tarp can help to protect the firewood from the elements while still allowing for air circulation.
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