How does humidity affect black powder?

Humidity affects black powder primarily by causing it to clump. Black powder is hygroscopic, meaning it can absorb moisture from the air. When humidity levels increase, the moisture in the environment can lead to the fine particles in black powder sticking together, or clumping. This can adversely affect its performance, as clumped powder may not burn uniformly or ignite properly when loaded into a firearm.

This clumping can result in inconsistent ignition and reduced accuracy during shooting. Consequently, it's essential for those handling black powder to store it in a dry environment and to be mindful of humidity levels when preparing and using it, ensuring that the powder remains dry and free-flowing for reliable performance.