Natural and artificial carbonation

Carbonation can occur as a result of natural processes: when yeast ferments dissolved sugars sealed in a pressure-tolerant bottle or keg; when underground volcanic carbon dioxide carbonates well water; or when rainwater passes through limestone into a cave and forms a stalactite. Or it can be done artificially by dissolving carbon dioxide under pressure into the liquid. Sometimes natural carbonation is called conditioning while the term carbonation is reserved for the artificial process.