Stevia is a plant and if the tea is organic, it should be fine. The stevia extract may be produced somewhere other then the US, but I wouldn't worry about it that much as its a natural sweetener.
A weaker culture from discarding part of the scoby usually just needs more time. If you are making kombucha regularly, just replicate the same thing every time and it will be consistent. I toss the scoby each time and it's fine. I use a bit more of the starter tea for the microbes though so it...
Yeah, that will drop the ph of the sweet tea if you don't have extra kombucha but already have a scoby. Otherwise, just start it smaller and build up your culture.
If this is the first scoby you've started from this culture I wouldn't be concerned especially because of the wide surface area. Carbonation sometimes gets caught as the scoby forms and causes uneven density in e coloration.
Scobys grow at different rates. One of the reasons you use starter liquid is to drop the ph of the tea to a safe level. Just like in sauerkraut or fermented foods, once the ph drops, mold and bad bacteria generally can't grow.
I think the bottom layer is generally the newest? I don't know that it matters though. If you are splitting it, just split it where it's easiest and toss half.
I've been playing around with ditching my scoby each time I do a new batch and letting a new one grow from the starter liquid. I think the larger it is the quicker the turn around, so if you don't mind a little lag time, you can always toss it and grow a new one
I got third in the sour beer category. They combined quite a few different beers together. Not sure where my other beer is or what it got. Very interested to see the score sheets. Any idea when those are gonna go out?
I entered this year! This is my first competition and wish I was able to see results already! I entered a Golden Sour into the American Wild category and a Gose into the Historical beer. Will be interesting to see what happens.