Kombucha is a very interesting part of tea culture, with origins that aren't totally clear. The most commonly believed origin says that it started in ancient Northern China. Kombucha is fermented sweet tea. During the fermentation yeast eat the sugar to make achohol, then, bacteria eat the alcohol produced by the yeast. In doing so they produce acetic acid(the thing that makes vinegar, vinegar) among other things and lower the alcohol content to negligible amounts. I won't get too much into the production of kombucha because that is for a later post.
I'm not one to preach the health benefits of tea(or in this case kombucha) or to tell people to go out and buy expensive "health" craze items. So I won't start now. The real reason you're learning about kombucha is because soon I'll be brewing my own and maybe you will as well! I am really excited about this because it's probably the only drink you can homebrew and actually save money. The 16oz GT's Kombucha bottles cost $3.50 each. The gear you need to make your own costs ~$30. It could be more or less depending on whether or not you make your own SCOBY. But homebrewing it a gallon at a time will pay for itself in 2-3 brews regardless of that.
Before I got started I wanted to figure out what I would like mine to taste like so I bought a few to taste and see. These are all GT's Kombucha: Original on the left(just tea, sugar and microbes, no fruit or flavor), Gingerade in the midde(just kombucha and ginger), and on the right is Citrus(just kombucha and lemon juice). I bought these at jewel, they had more flavors, these ones simply appealed to me the most. I enjoyed the original one the most as it was definitely the sweetest and smoothest. The ginger and lemon ones I thought were a little too harsh and lost the tea flavor all together. I think I would enjoy them more if there weren't as much ginger or lemon. Maybe as nuanced flavors instead of these big flavors that conceal the original taste. I'll definitely experiment with different teas and flavors in my own brewing.