According to various embodiments, methods of increasing a shelf life of a gas-generating material comprise: including a C.sub.8-C.sub.18 hydrocarbon in a mixture used to coat the gas-generating material. This gas-generating material may be used in a cement composition to generate gas therein after the composition has been placed in a wellbore. The coating surrounding the gas-generating material serves to delay the reaction for producing the gas until desired. The gas may serve to inhibit gas migration from an adjacent subterranean formation into and through the cement composition before it sets into a hard mass. Coating the gas-generating material with the mixture may ensure that it can be stored for a relatively long period of time (e.g., up to 1 year or longer) without being concerned that it might experience sintering and thus react prematurely.