Other than warmer temps, how is this different from sanitizing my equipment with StarSan?
Am I leaving viable wild yeasts behind in my fermenters and kegs if I just use StarSan?
One huge difference is perhaps obvious, but when I am sanitizing my equipment it's already _clean_ - I've rinsed out all the chunks, soaked it in PBW, scrubbed it with soap and water, etc.
To be fair, the ultimate answer to your second question is _yes_ - There are always going to be some small number of mold spores or wild yeast cells left over even after sanitizing, no matter what you are using. Sanitizing != sterilizing. So, you are correct that StarSan isn't going to totally eliminate all wild yeasts (and may in fact not do that great a job on these critters), but as long as you do a thorough job in cleaning, and of course pitch enough yeast, it shouldn't be an issue... At least up to the point where it's no longer possible to clean your gear properly (scratched buckets, funky hoses, etc).
It may explain a subtle "house flavor" in the last few batches that some identify as mildly "phenolic."
If you are trying to get at the source of these mildly phenolic flavors, I would start first by asking:
- Am I able to control my fermentation temperatures adequately?
- Is my fermentation temperature in the correct range for the strain of yeast I'm using?
- Did I pitch enough yeast?
Not to say that you don't have a colony of bad bugs in your equipment. But I would guess that it's more likely an issue with your fermentation.