Originally Posted by Rahahb
If it ain't broke, don't fix it.
You want the scoby to have access to oxygen, hence the cloth/paper towel, cheesecloth, etc. instead of an airlock.
Using this method, you will get all the oxygen you need. No need to introduce an extra level of complexity to something as simple to make as kombucha.
And to the op, starsan should be fine in reasonable quantities.
This is all right.
The surface requires access to the open air, acetobacter require O2 for aerobic processes. If you close off your vessel with an airlock, you will switch to anaerobic processes once the O2 in suspension is depleted. You want all the O2 in the liquid for the yeast to replicate. Additionally, kombucha is deliberate contamination. It is ideal to allow wild yeasts and acid-loving bacteria from the air to fall into the brew. They're very good at overwhelming invaders provided they have the right environment. If you use an airlock, you will get fermented tea, but not kombucha. The anaerobic bacteria take much longer to work than the aerobic do, and you will have little to no pellicle development.
StarSan will work, but remember, the point of kombucha is to utilize wild yeasts and bacteria from the air; StarSan kills wild yeasts and bacteria.
When I need to clean my bottles or fermentors, I wash with dye and scent free dish soap (if necessary[usually only when new]), rinse VERY well with tap water, then rinse with white distilled vinegar and let stand for a few minutes to dissolve any soap residues or until I'm ready to use it whenever. If the container is for bottling, I'll rinse the vinegar off with distilled water. If it's for fermenting, there is no need in rinsing as the kombucha will make vinegar anyway; the residual vinegar will assist with lowering the pH and protecting it from molds and other unwanted microbes.
I haven't had any trouble when I experimented with StarSan, but it seemed to prolong lag time. Could be coincidence though.