I would say at the very least, the best wood for burning should contain under 20% moisture. You will find some wood with 25% moisture that is still okay for burning but they're not the ideal standards.
The kind of wood in question is also a factor that can determine the appropriate moisture level. Timber, for example, is one of the most popular woods for burning and it generally is dried up to about 10 - 15% moisture by professionals.
This is the level where it is dry enough for optimal burning but still retains much of its original strengths and elasticity. Timber can also be dried completely to a state known as the "bone dry" state. This is done because wood tends to regain moisture from the atmosphere anyway.
Kiln drying your wood gives you the best control over the humidity, temperature, and a host of other factors that guarantee optimal results. To learn more about kiln drying, feel free to click the link here.
