I won’t get into whether kombucha actually works as some people say it does, but suffice to say that I use the stuff and like it. However, at $3 a bottle, it is rather expensive. I wanted to start brewing my own at home as an interesting biology project and to save money, but I don’t have a starter. Can I use a bottle of the store bought stuff to start my own? I’ve looked over a number of websites about Kombucha brewing but none seem to mention this as a possibility. I find this a bit odd since it seems like it should be the easiest way to start a batch at home (assuming it’s possible). I’m not a biologist, but I can’t see why I shouldn’t be able to do this-- yet, it seems like one of the kombucha fanatics out there would have offered this as one of the methods for starting your own kombucha brewing process. Any insight?
I’m not sure if you read my post, Silenus, but my question was not about how to brew, but rather about whether I can use a bottle of commercially bottled kombucha tea as a starter as an alternative to a “mother” culture.
As long as it isn’t pasteurized before or after bottling, then the answer is yes. Live cultures are live cultures.
The bottles that I buy say that it is “raw kombucha” and the nutrition label does mention that it contains some-odd billion active cultures. It jsut seems very strange that out of all these enthusiast websites that mention brewing, none mentions that you could start cheaply with one of these bottles. They clearly acknowledge the availability of this product in certain markets, but yet they suggest buying $15-20+ starter kits. Even though my brain was telling me that “a live culture is a live culture”, the voice in the back of my head was saying, “surely they would have mentioned this possibility.”
That’s because everybody wants to sell you the cultures. 
silenus, thanks for that link-- actually it did have the answer i was looking for, buried deeper in the page. I had thoroughly read over that site before, and didn’t see it in the FAQ for some reason. Well anyway, in case anyone’s interested:
If there is a parallel betwen this stuff (which I’ve never heard of) and Belgian Ales, which have an active yeast culture in the bottom of the bottle, then the answer is maybe.
With Belgian ales, people want to try to copy them but have been generally unsuccessful due to the fact that the early fermentation (responsible for the majority of the taste and mouthfeel) is accomplished using native, airborne yeasts which only grow in one place: Belgium. Once the primary fermentation is over and they’ve let it sit for a while, they use a different blend of yeast at bottling time to get the finishing flavor and carbonation into the ale. People who use the ale sediment at the bottom of a bottle of Chimay Ale, for example, end up with something that doesn’t necessarily have anything to do with the majority of what goes on in the making of Chimay Ale, even though it came straight from an original bottle. Kind of like putting a Cadillac body onto a Lincoln. It might be a great car. It might look great. But it ain’t a Cadillac.
Hope that was confusing enough.
This stuff is different. Finishing yeasts in Belgians are something any home-brewer should know about.
(I just use my own cultures for Belgians…I have several strains that are on their tenth or twelfth batch!)