From: Wild Fermentation by Sandor Katz
Timeframe: 7-10 days
Ingredients (for about 1 quarts/1 liter):
1 quart/liter water
1/4 cup sugar
1 tablespoon loose black tea or 2 tea bags
1/2 cup mature acidic kombucha
kombucha mother [SCOBY (Symbiotic Community Of Bacteria & Yeast)]
Mix water and sugar and bring to a boil in small cooking pot.
Turn off heat; add tea, cover, and steep about 15 minutes.
Strain the tea into a glass container. it’s best to use something wide; kombucha needs adequate surface area and works best if the diameter of the container is greater than the depth of the liquid. allow the tea to cool to body temperature.
add the mature acidic kombucha. when you obtain a culture, it will be stored in this liquid. Save a portion of subsequent batches for this purpose.
Place the kombucha mother in the liquid, with the firm, opaque side up. [The shiny and lighter in color side is the top.]
Cover with a cloth and store in a warm spot, ideally 70° to 85°F.
After a few days to 1 week, depending on the temperature, you will notice a skin forming on the surface of the kombucha [doing as best you can to NOT disturb the newly-forming SCOBY (“skin”)]. Taste the liquid. It will probably still be sweet. The longer it sits, the more acidic it will become.
Once it reaches the acidity you like, start a new batch and store your mature kombuchas in the refrigerator. You now have two mothers [SCOBYs], the original one you started with, and a new one, the skin that formed on your first batch. Use either the new or old mother in your new batch, and pass the other one on to a friend (or the compost). Each generation will give birth to a new mother, and the old mother will thicken.
Note: If you don’t have access to a SCOBY to begin your kombucha, you can also use the liquid from a store-bought bottle. Just brew the tea as described above and add at least half the bottle of store-bought kombucha. You should see a SCOBY forming in a few days.