[SIZE=10.5pt]I haven't been comfortable mixing it and keeping it any significant length of time. I've often mixed it and kept it around a few days, though. I’ve never had a problem keeping it in regular plastic spray bottles, but I’ve over-soaked beer lines (like forgetting them soaking for a week or more) and after a while the exterior gets gummy and they discolor.[/SIZE]
[SIZE=10.5pt]My understanding is SS has both a detergent (not a harsh one as I understand it, as yeast will actually feed off it) and low pH acids that work together as antimicrobials. I've heard podcasts with Charlie Talley where he recommended keeping it in a cool dark place after mixing and continuing to use it until it starts to get cloudy. Even after becoming cloudy, though, I've tested the pH as remaining in the low/mid 2's. I'm not sure what that means for efficacy, though - when it’s cloudy but the pH remains in the zone - with Charlie saying “use until cloudy” and other secondary sources I’ve read indicating monitoring pH, alone.[/SIZE]
[SIZE=10.5pt]Another thing Charlie said on a podcast is that the FDA restricts what 5-Star puts on labels. For instance, 5-Star indicates soaking for a full 2 minutes, but Charlie said Star San kills much faster than that, they just aren't allowed to advertise that on the product for whatever reason. I wonder if that might explain why the label says to use it immediately, as Bou posted, which seems in conflict with what I've heard as to it lasting for at least a little while.[/SIZE]
Oh, and FWIW I bottle mix like Tybo does, usually rounding up the ml's just a little for smaller batches. When I first started using the stuff I was going through it way too fast.
