In making kombucha, starting from a commercial bottle of kombucha was not a bad idea 5 years ago but the industry has changed. The day of the small micro-kombucha brewery making unfiltered, raw kombucha is coming to an end.
These days, many breweries are using additives and filtration processes to help control the fermentation process - a standard practice in the commercial brewing world for established industries like beer and wine. Sure, it can be a relatively inexpensive way to get going, but you may be propagating something you didn't intend. For this reason, it is best to start a batch of kombucha using a fresh, straight-from-the-fermenter SCOBY.
Think about it like this. A town of 5,000 trying to build a new meeting hall will have a hard time not building more than a room with four walls.
A town of 5,000,000 will be able to not just build a room with four walls but a whole structure full of rooms, passageways and fun things to do (definitely an amazing kitchen).
The same can be said for a colony of kombucha microbes coming from a commercial bottle of kombucha (town of 5,000) and a fresh kombucha SCOBY and starter (town of 5,000,000). There is really no comparison. The fresh SCOBY will brew a potent delicious kombucha the first round, in the normal 10-14 days, where as the commercial brew starter may not even form a new SCOBY let alone ferment a perfect batch in 10 days.
We get photos all the time of peoples brews that have molded after trying to start a batch with a bottle of the popular brands of kombucha.
Don’t waste your time or ingredients trying to build a colony from a subpar SCOBY. Start with a lab-grown, fermenter-fresh SCOBY and get perfect brews right away. Because let's get real, who wants to wait more than 10 days for their ‘buch?
Stay tuned for Starting from a Commercial Bottle, pt. 2!