An anaerobic jar works when an individual places water, sodium borohydride, sodium bicarbonate and citric acid in a sealed jar along with some microorganisms. The solutions react due to a palladium catalyst to form hydrogen, carbon dioxide and condensation, using up the oxygen to create an oxygen-free or anaerobic environment.
Because the jar is oxygen-free, only certain types of microorganisms can thrive and grow, such as anaerobes. Aerobes, which require oxygen to live, will die in this environment.
In order to make an anaerobic jar or GasPak anaerobic system, an individual needs a polycarbonate jar, a GasPak envelope, a lid with a gasket, a methylene blue strip, a mesh pouch with the palladium catalyst, inoculated plates that contain the microorganisms and the necessary chemicals. He first adds the sodium borohydride, sodium bicarbonate, citric acid and water to the GasPak pouch that is then placed in the jar. He places the microorganisms in the jar as well. After sealing the jar with the lid, he waits for the chemical reaction.
The chemicals and water form hydrogen and carbon dioxide. The hydrogen then reacts with oxygen in the air, resulting in condensation. This removes all the oxygen from the jar, turning the methylene blue strip white to show a lack of oxygen and giving the microorganisms an environment in which to grow.