I harvested the yeast from a bottle of Weyerbacher Twelve and built up a 1 liter starter. Unfortunately my brewing was delayed, and there was a huge krausen on the starter for 5 days before I decanted and pitched it. I figured the yeast might not be at their most active, but would still do their thing. I was mistaken, and now a week has gone by with no sign of fermentation. I just checked the SG and confirmed that it has not changed, those yeasties are dead as doorknobs.
I know it is considered very bad and unsafe to keep unfermented wort around. This little batch has been sitting in its sanitized glass bottle with presumably no yeast activity for a week. If I pitch a pack of dry yeast in there tomorrow will it probably all be fine, or do I have a festering pile of infection that just hasn't reared its head yet? When I took the SG reading it smelled fine, and I worked under a cloud of Star San to keep it safe.
Of course I'm going to do it regardless of what you say, since there's no point in tossing a batch... well, ever. But what should I be expecting?
EDIT: Oh, second question: re-aerate the wort since nothing has happened yet, or leave it alone?