Useful tips for brewing kombucha tea
It's not an exact science
You don't need to be a perfectionist when making Kombucha. Scobys are quite flexible with the conditions they will grow in so (within reason) you can vary the amounts and types of sugar, tea and flavourings you use without too much risk of 'killling' your scoby.
Many people make it in many varying ways so you can experiment and try different things when making Kombucha to get various flavours, strengths and volumes etc. Just keep the basics in mind (always have sugar, some black/green tea and a warm temperature) and always have more than one jar going so that if one variation fails, you have a backup.
Some variations from the basics though will slowly weaken the scoby health and viability (due to less than ideal conditions or ingredients) so if your scoby(s) start looking 'not that good', then go back to a standard black tea and sugar only brew for a few brews to revitalise your scoby.
How to flavour Kombucha
There are many ways to flavour your Kombucha. You can add fruit flavoured tea (fruit infusions) when you make up a brew. You can add fresh or dried fruit when bottling it and leave for another 2 or 3 days before drinking (a 'second ferment') or you can simply add some fruit juice, fresh ginger or other spices to your glass of kombucha when drinking it.
Exact quantities not vital
The amounts of sugar or tea used need not be exact. A little too much or a little too little sugar or tea (from suggested amounts) will only vary the outcome, not ruin it. Extra sugar will make it take longer to brew, a little less will means it doesn't take as long. Extra tea will just give a stronger flavour and thicker scoby.
So don't worry if you don't or can't use exactly the amounts of ingredients recommended by any given recipe.
Have more than one brew
Once you've got a few brews under your belt, always have at least 2 separate jars of Kombucha brewing at a time so that if one gets contaminated or dropped on the kitchen floor or you want to give one to a friend, you still have another to keep yourself going.
The old addage of "Don't keep all your eggs in one basket" was originally derived from the "Don't keep all your Scobys in one jar" principle.
Continuous brew Kombucha
If you're thinking a 'Continuous Brew' system of making kombucha sounds like a bit of you, just keep in mind that as you add sugar more regularly to a 'Continuous brew' setup, it means the sugar level in what you drink will be higher than normally made Kombucha. So if you're trying to avoid high sugar levels, the 'Continuous brew' method is not for you.
The shape of a Kombucha Scoby is determined by the shape of the container it grows in.
As the new (baby) forms on the surface of the brewing container covering the whole surface that is exposed to the air (independent of the mother culture), it will grow into whatever shape the jar is at the top of the liquid - round jars give round scobys, square jars give square scobys etc.
Not all Scobys are created equal
Kombucha Scobys are not always perfectly smooth on top.
The many variables of temperature, amount of sugar and type of teas used will often give slightly different results.
Colder temperatures in winter will give thinner scobys, different teas will give different coloured scobys and differeing balances in the bacteria and yeast populations can give smooth scobys or lumpy/bumpy surfaced scobys.
All will ferment your Kombucha just the same though and are quite normal.
Make your Mothers float if you can.
When combining a new batch of sweetened tea with a scoby and starter tea, add the scoby carefully to try and keep it floating on or near the surface. Try and lift it up with a spoon or utensil if it wants to sink, but if it insists on sinking then leave it - it's still ok. If you can make the 'Mother' scoby be on or near the surface, the newly growing 'baby' scoby will likely adhere to the mother to make one bigger scoby. There will also be small amounts of air trpped between the layers making it float easily next time.
Multiple generations stuck together are easier to handle and tend to give a slightly better fermented brew of Kombucha.
Keep the temperatures the same.
Make sure the temperature of your new sweet tea is the same as your scoby and starter tea when adding them together.