Place the tea bags in an 8 cup jug and add the boiling water.
Allow the tea bags to steep until the brew is cold, then squeeze out the tea bags and discard.
Add the raw sugar and filtered cold water to the jug.
Stir to dissolve the sugar, then pour the sweetened tea into the drink dispenser.
Add the cup of kombucha to the drink dispenser, and slide in the kombucha SCOBY.
Cover the mouth of the vessel with cloth or muslin, and secure with a rubber band. Do not put a lid on the jar, as kombucha requires oxygen for fermentation.
Set the drink dispenser aside somewhere it will not be disturbed, and wait for a new SCOBY to form on the top of the brew. You will also see small bubbles start to develop in the brew.
Start tasting the brew once a new SCOBY has formed on the top of the liquid. The brew is ready when the taste is to your liking. I prefer mine to be quite acidic but other family members prefer a sweeter brew. If the brew is too sweet, allow it to ferment for a further day or two then taste again.
Once the kombucha is to your liking, draw off enough of the brew to either drink or secondary ferment using the tap at the bottom of your drink dispenser and then repeat the process.
Kombucha activity is very temperature dependent, so the tea will ferment faster in warmer weather. Mine takes about one week in summer and slightly longer in winter.