How to make Kombucha AKA the "Immortal health elexir"

Kombucha claimes to have a number of health benefits due to it's antioxidant and probiotic properties. It's a fermented drink made of tea and its history dates back to at least 2000 years ago in China where it was called the "Immortal health elexir". I have no hopes of becomming immortal, but I like to experiment in the kitchen so I tried to do my own kombucha. It's a great drink if you want to drink something refreshing and not too sweet. Kombucha have a bit of a sour taste, almost like vinegar. Have you tried it?
(let me know in the comments)

Ingredients:

1 SCOBY, the "kombucha mushroom"
1 liter fresh water
2 bags of ecological green tea
0,5 dl sugar (the mushroom will use it during the fermentation process)
Some berries, ginger or orange for the flavour. I used strawberries from the garden.

How to:

First of all you have to got a SCOBY, a living mushroom like symbiotic colony of bacteria and yeast that make the fermentation process possible. I was lucky to have a friend that got one left (that one has now grown in to three new ones). The SCOBYS are stored in at least 2 dl kombucha drink. I've also seen that you can buy one at Amazon or other online stores.
Boil the water. Add the tea and wait for 15 minutes. The SCOBY needs the nitrogen from the tea.
When the tea is 40 celsius, add the sugar and pour into a container of glass or porcelain.
Add 2 dl kombucha drink and the SCOBY.
Fastening a towel over the opening with a rubber band and store in a dark place at about 23 celsius for 10 days.
After 10 days, make sure your hands are clean and put the SCOBY in a new container with 2 dl of the kombucha. Filter the drink.
Put some flavour to the kombucha, about 2 dl of juice or fresh berries. After 3 days in the fridge, the sugar from the fruit has naturally carbonated the drink.
Store in the fridge in bottles. Ready to drink!