With snow, rain and plastic deterioration from the sun, it is important to check your pellets once a month if stored outside to ensure they are protected well. We are happy to provide extra cover bags if you need them. If your pellet fuel is stored in the basement or garage, use 2×4’s to keep the bags off of the cement floor and make sure there is spacing from a cement wall. Pellets can pull and absorb moisture from the cement and swell up. *Be sure to never put swelled or wet pellets in your stove’s hopper. Humidity or moisture in the air will not hurt your pellet fuel, and bulk fuel is fine being kept exposed. If the storage area is wet and damp to a point that moisture could physically drip, then it is recommended to cover your pellets appropriately. Wood pellets have an infinite shelf life as long as they stay dry.