The present invention is a controllable gas generator which includes an egated container having a top and a bottom. Two different liquids and pellets are utilized, the pellets being nonreactive with and floatable in a first one of the liquids and reactive with and nonfloatable in a second one of the liquids. The first and second liquids are disposed in the container, the first liquid being denser than the second liquid so that the first and second liquids form an interface. A partition is mounted in the container below the level of the interface for dividing the container into top and bottom compartments. The pellets are disposed in the bottom compartment with the first liquid, and a valve is mounted in the partition for dispensing the pellets. With this arrangement, an opening of the valve will allow pellets to exit therethrough and ascend in the first liquid to the interface where the pellets will react with the second fluid to generate gas.