Kombucha

Kombucha is easy to make, not to mention yummy and good for you too. First, you need a 'starter' in the form of a pancake-like 'mushroom' or scobie, and some live kombucha tea. You can get a kombucha starter from a friend already brewing Kombucha. To make 1 litre of kombucha you need:

1 litre (2.1 US pints or 1.76 UK pints) of water (aired tap water, filtered water, hard water, spring water, mineral-rich water). Your brew needs the trace minerals found in most water. Do NOT use distilled water, reverse osmosis (RO) water, or alkaline ionised water
60-90 grams (2.1-3.2 oz) of sugar (raw or white)
3-5 grams of tea leaves (1 heaped teaspoon). You can use ordinary black tea, oolong or green tea
A saucer-sized piece of kombucha scoby/mushroom from a previous brew
50-100 ml (2-5 tablespoons) of kombucha liquid from a previous brew (less required if it is strongly acidic)

Method

Boil the water and the sugar
Add the tea, and leave it to sit for at least ten minutes before removing the tea leaves or bags. I usually leave them in until it is completely cool
When your tea is at room temperature, you can pour it into your brewing bowl and add the mushroom and the starter. It is important that it has cooled completely - if it is above 35C, you can kill the starter
Cover it with a clean fine cloth that lets it breathe
Put it in a quiet place out of sunlight, where it will remain at a stable temperature between 23C and 30C
Use a bowl made from glass, china, enamel or glazed terracotta. Metal, lead crystal and cheap plastic are unacceptable. Kombucha reacts strongly with any metal, and can take up toxins from some plastics. The bowl should have a wide top for good breathing
The starter scoby/mushroom usually sinks. Within a few days, a clear or translucent thin skin will start to form on the top of the liquid, and it will smell fermented. The brewing time depends on the temperature, and your taste requirements. After 6-12 days, the new mushroom culture will be a centimetre thick, and grey, cream or peach-coloured
Before you bottle your brew, remove the mushroom culture that has formed on the top, and keep a saucer-sized piece for your next brew. Also keep some of the brew as a starter. Stir up the sediment that has formed in the bottom of the bowl, and then bottle it in glass bottles, tightly capped. The sediment contains yeasts that make it fizzy. It needs a day or two after bottling to build up enough pressure to make a fizz. I put it in the fridge for a few hours before serving, otherwise the froth overflows when you open it
Making Kombucha has almost as many variables as does making wine. The longer it is left, the sourer the tea will become. You can use a variety of teas, and generally, the finest teas make the best brew
Normal kitchen hygiene is OK - your equipment does not need to be sterile