Kombucha (first fermentation) Fill a ~4L glass jar with water, leaving space for an additional cup of liquid. Pour about 1.5L of water from the glass jar to a 3L pot. Set aside the now half-full jar. Put the on high heat. Add black tea leavese.g. Earl Grey to the heating water, mix and bring to a simmer, then leave off the heat for 10 minutes for the tea to infuse. Cool down the by diluting it with cold water from the jar. Set aside the jar with remaining water (leave at least a few cups to minimize the thermal shock to the glass jar later). Pour the infused and cooled tea back into the , through a sieve to catch the few floating leaves. Most of the tea leaves usually stay at the bottom my pot. Add sugar to the tea jar and mix until it dissolves completely. After making sure that the sweet tea is not hotter than 40°C, pour and stir in a starter culture of raw kombuchai.e. not pasteurized, either from a previous batch or a bottle of raw kombucha from the store. Note that the SCOBY is the culture of bacteria and yeast that live in the unpasteurized kombucha, not the pellicle that can form on top of the liquid. Cover the jar with a cloth and leave the inoculated sweet tea in a dark place, ideally between 20°C and 25°C. A pellicle should form at the top in the following days and some bubbles may get trapped underneath, but do regularly make sure that the culture is not colonised by other organisms: it should have a pleasant smell, and no fuzzy patches on the surface. Ferment to preference, until the brew has acidified and consumed enough sugar. I've measured the sugar content with a refractometer and my brew starts at 6-7% and I wait until 3.5% for the second fermentation.