The present invention pertains to a brew head assembly comprising a gear-driven locking assembly and a sealing assembly, whereby the brew head assembly is capable of sustaining pressures up to 20 bars. A first electrode is covered with a flow passage area provided in the insulating region so as to neighbor the neighboring region and extend over the whole length of the insulating region in the direction of flow of liquid. The composition can be formed by combining the dry base and the viscous additive into a first mixture and adding all or a portion of the saline solution to form a crumbly consistency. The invention also relates to an installation that can be used for implementing this process.