A process for extracting aromatic substances which are contained in sealed cartridges by injecting water for prewetting the substance in the cartridge, injecting air into the prewetted substance and injecting water for extraction of the substance. More particularly, the aromatic substances which are extracted are for the preparation of a beverage and are contained in cartridges which have a top portion capable of being pierced by an injector and a base portion having a membrane provided with a line of weakness which breaks during the extraction process with a filter being provided between the membrane and the substance to be extracted. The prewetting water is injected into the substance in the cartridge at a pressure of between 2 kg/cm.sup.2 and 3 kg/cm.sup.2. Air is injected at a pressure of between 3 kg/cm.sup.2 and 6 kg/cm.sup.2 for opening up irrigation channel pathways in the prewetted substance and for applying a force to the cartridge membrane greater than the breaking resistance of the line of weakness for tearing the membrane along the line of weakness. Water is injected into the substance in the cartridge at a pressure of between 8 kg/cm.sup.2 and 16 kg/cm.sup.2 for extraction.