The preparation liquid is at least as important as the mushroom and brings the necessary bacteria and yeasts into your drink. These then transform your sugar-tea mixture into kombucha. In principle, the preparation liquid is finished Kombucha and after the first brewing process you simply add some of the finished Kombucha again and again.
Always use about 10% of the total amount of Kombucha to be brewed. For 3 litres of Kombucha you want to brew, add 300 ml of the liquid.