and now for PART II:
Add that sugar! Give it a good stir until it is completely dissolved. (May I suggest that you add a quarter-cup of brown sugar too if you're using just green tea ... it helps it ferment faster)
VERY IMPORTANT: Let the sugar-tea cool to room temperature before the next step!
The culture is a living organism (actually about 30 distinct species) and will die on contact with hot liquid. Depending on the volume of your sugar-tea, it could take many hours to cool down. You can take a shortcut by adding a bag of ice (if you add ice directly, make sure it's made from filtered water).
Once cooled, it's time to add the culture. Make sure your hands are clean, but you don't have to be delicate - it's a tough, resilient symbiotic structure.
You should have received your culture in an acidic solution (from its original batch). Add this too - it will kick-start your ferment. If you weren't so lucky, you can add a tablespoon or two of organic apple cider vinegar.
Cover your containers with cheese cloth and secure with a rubberband. This serves several very imperative functions: 1) it keeps fruit flies and other unsanitary pests out; and 2) it prevents condensation from occurring, which could lead to mold and other unsavory issues.
Keep the containers out of direct sunlight (UV rays kill the microorganisms) in a warm place. The warmer, the better. The culture likes to hang out in temperatures around 80F. I keep mine on top of seedling heat mats (when I'm not using them to start my veggies in the greenhouse), but you could put yours near the stove or wrap a cozy around it.
Let it go for about a week, but this can vary drastically depending on the conditions. It is ready when it tastes sour, not sweet. You will notice some carbonation, but to get it really fuzzy, you will have to send it on a second ferment. Here's how:
Sterilize old glass drink bottles and their lids. Fill with the kombucha and add a pinch of granulated sugar. Seal tightly ... very tightly. Keep in a warm, dark place for 2-4 days. Essentially, you have created anaerobic conditions, and the CO2 has no place to go.
One more thing: If you're going to add flavor, do it when you bottle it. Stick to organic fruit juices and herbs or teas.
ENJOY!