No secret, heat a gallon of water, and a cup of sugar….until sugar is dissolved, but don’t boil. Turn the heat off and add 8 black tea bags. I literally use the cheapest store brand….steep for 5 minutes and remove the bags without squeezing. Cover and let cool to room temp, overnight is best. Add that and the starter to the jar and cover. The magic happens over the next 15-30+ days. The yeast eats the sugar, slowly making the kombucha less sweet and more tart…you’ll find your preferred spot to start the second ferment eventually…..mine is 25 days, it’s a bit more tart than sweet, but not overly acidic. Once you add the fermented kombucha to the bottles with more food for the yeast (in the form of fruit/aromatics) and contain the co2 (capping the bottles) it will naturally become fizzy