I've been making my own kombucha for 7 years, here are all my tips!
You will need:
Starter kit (SCOBY + plain kombucha, about 10% of total)
Mason jars for the 2nd fermentation
Glass bottles to store kombucha (you can also store in Masson jars)
Where to find your scoby? They sometimes sell starting kits in natural food stores. You can also find someone online that will give or sell it to you for next to nothing (It is common practice in the kombucha community to share scoby). Another trick is to buy a bottle of kombucha, and leave the content in a mason jar on the counter (do not tighten the lid!) until a scoby forms on the surface.
Or you can ask me and pass by my home to pick it up!
For 4 liters
Tea (black, green or white, to taste) - 3 bags
Herbal tea - 2 tea bags
1.5 cups of sugar
Boil the tea. Dissolve sugar. Place in container. Let cool (never scald the scoby and starter!) or add fresh water if needed. Put the mother and the starter. If you are using tea leaves, strain before putting in the pot with the mother. There will probably be some leaf particles left: don't be surprised to find them ''stuck'' on the scoby.
Never add any flavor or ingredient in the first fermentation, it could damage the scoby. Cover with a cheesecloth or cloth, with a rubber band. There will be a lot of carbon dioxide produced by the fermentation, so don't seal the lid because of the risk of explosion! It is still necessary to cover it because it attracts fruit flies (especially in summer).
Put the large jar of kombucha in a dark place, ideally at 27 degrees Celsius (the warmer it is, the faster the fermentation will be). Usually it takes 5-7 days to get the right level of fermentation, but there are many factors (room temperature, amount of sugar, vigor of the scoby and the culture). Taste after 4 days, you will know if it is to your taste. When it is too vinegary, you can't go back (see here ideas for kombu that is too vinegary).
Now it's time for the 2nd fermentation: keep the mother and 10% of the liquid aside in the fridge for the next first fermentation (or start a new batch right away).
The purpose of the 2nd fermentation is to 1) flavor the kombucha 2) make it more effervescent. If you want a plain kombucha that is not too fizzy, you can skip this step and bottle it directly.
I like to pour into 750 ml Masson jars and make different flavors. First, put the ingredient of your choice, fill with kombucha, leave a little air, don't fill to the top, and then put the lid on.
ginger (grated or in pieces)
fresh fruit (pineapple, I love it),
spices (cardamom, cinnamon, coffee),
herbs (mint, basil),
citrus fruits (just the zest or pulp too)
scented tea (like David's tea or any other),
And of course: any combination!
The sweet fruits will activate the fermentation, so no more bubbles! (beware of explosions with pineapple!)
The kombu will take the color of the fruits (so consider it if you want a nice color)
In order to have effervescence, the kombucha from the first fermentation must not be too vinegary and the carbonic gas that will be created in the second fermentation must be "trapped". But be careful: do not leave the jars unattended! The gas will accumulate, you have to open them (to ''burp'' them) from time to time to let the pressure out. As with the first fermentation, the amount of gas will depend on the sugar content, the external temperature, and, for this second fermentation, on the tightness of your jar. Mason jars are practical because you can adjust the tightness by tightening more or less.
Obviously, the second fermentation is slower because the mother is no longer there, but there are still some particles of the mother. I like to keep the jars in view at the counter until the taste, color and bubbles are to my liking. If it's not effervescent enough, you can add a little sugar or juice (as this contains sugar).
Once your kombucha is to your liking, you must store it in the refrigerator to stop all fermentation. Filter and bottle. Kombucha keeps for a very long time, but the taste will change a little over time (but who keeps a bottle in the fridge for 3 months?).
Keep a portion of your kombucha to start a new fermentation. If you want to take a break, simply store the mother and 2 cups (approximately) of liquid in a Mason jar in the refrigerator.
To share your mother: you can easily cut it and share it with a friend: it will simply grow and regain its shape (a mother always perfectly fits all available surface). This is quite beneficial, in fact, and allows you to renew the mother.
This site has good answers for you!
If not, don't hesitate to write me.