The slimy jellyfish like lump in this jar is the 'mother'.
You need the mother first...I don't know how to make the mother from scratch, coworker just chopped a bit off hers to bring in. It is a fungus. It looks just disgusting.
Put 2 black teabags and 3/4 cup of sugar in a container and brew with 1L of freshly boiled water. Let steep until cool. Pour into a ceramic or glass bowl and tip in the mother and liquid it's stored in (some kombucha from previous batch).
Leave for at least 4 days covered with a tea towel in a dark place.
This is what will happen. I could have left it an additional day but got lazy. It goes a bit fizzy and grows a nice thick layer on top (which is the new mother).
Scoop out the new mother (I believe it's called a scooby?) and throw out the old mother. Put new mother in a jar with a little bit of the kombucha.
Strain kombucha into a glass or ceramic container and flavour as desired...I just put some lemon slices in. Store in fridge.
The entire process is quite disgusting but interesting. The fungus feeds on the caffiene and sugar. It's probiotic. I wouldn't drink it on an empty stomach because of the probiotics...
Anyway, there you go. Kombucha. I've currently got my second batch in the pantry, and will leave it a little longer this time. =D