To make a new culture, cut a 1.5 inch piece off your scoby. Add this to a quart of finished Kombucha in a glass bowl, and allow it to ferment for 3 to 4 weeks, until the scoby is thick and as wide as the surface of the liquid.
It's always a good idea to keep an extra scoby refrigerated as a backup in case your batch is contaminated.
If you don't bottle the fermented tea it will continue to ferment and turn vinegary in taste. You won't want to drink it.