The powder is sucked in by the strong negative pressure created by the ZC-reactor head. Immediately after contacting the liquid phase, the powders are instantly wetted and thoroughly dispersed. This process is actually completed before the powder is fully hydrated. Due to the extremely short time shear forces are applied, the process is a very gentle one. In most cases a single pass operation ensures that even when processing extremely shear-sensitive thickeners and gelling agents, the highest viscosities are achieved.