Start by assembling all your ingredients and tools. When making kombucha it is important to ensure that all your tools are clean and free of debris to avoid any contamination and mould during the fermentation process. I usually wash everything with dish soap and a fresh sponge then rinse with scalding hot water to sterilize.
Firstly you'll want to brew your sweet tea. Boil 3 cups of water and add to your bowl or stainless steel pot before adding in the tea. Allow to steep for 10 minutes before removing.
Next stir in the sugar until dissolved. Allow the tea to cool completely before proceeding to the next step - hot tea will kill the yeasts in the kombucha culture so you don't want to rush this step. I sometimes transfer the tea into large glass bottles and cool in the fridge to speed the process up, however.
One your tea has cooled, add it to your brewing vessel along with your SCOBY, starter tea and the rest of the water. Stir gently with your wooden spoon to make sure the mixture is well combined.
Cover your brewing vessel with your breathable cover and rubber band.
When your tea has cooled down add your kombucha mushroom culture along with the starter tea into your brewing vessel.
Place your vessel in a dark but well ventilated place. I tend to keep mine on my counter tops for easy access, but a pantry or open closet could also work.
Depending of the temperature of your home, your kombucha may ferment slower or faster (warmer climates will result in quicker ferment). Wait 4 days before tasting the kombucha - if it's too sweet still then continue to brew for a few more days, tasting it every day or so until it has reached the desired level of tartness. If it's tasting a touch too sour, then make a note to shorten your brewing cycle next time and bottle it straight away. Taste is subjective, so with time you'll figure out the balance of sweet and tart that appeals to your palate. I personally like to bottle it when it's tart but still slightly sweet as I find that works best for my second fermentation.