A process for making a fermented liquid drink comprising separating and selecting a colony of a suitable bacterial strain, preparing a seed liquid from a live culture of the colony, and culturing the seed liquid in a large scale liquid culture. The bacterial strain is of the genus of Acetobacter or Gluconobacter. The seed liquid is prepared by culturing the colony on a slant surface on a solid medium, followed by multi-stage active liquid culture. The multi-stage active liquid culture has an initial stage of small scale active liquid culture and at least one enlarged scale active liquid culture.