How long can I leave Star San in a keg?

[Parsaver]

I was all excited to keg my first keg of cider today and tragedy struck and was avoided.

I filled the keg with StarSan and sealed it to shake it around. When I went to get the carboy from the fermenter, I dropped it. The miracle is, it didn't break. It rolled on the floor and the air lock didn't even come off!! The bad side is all the yeast got agitated and mixed back in. Going to cold crash it overnight to let it settle. Can I just leave the sanitizer in the keg until tomorrow?

 

[jekeane]

Certainly, many people keep their kegs full of star san then push the star San into an empty keg to minimize oxygen and make sure everything stays sterile.

One caution would be if you made your star San with tap water that has chlorine it can react and create an odor and Flavor over time that could possibly carry over into your kegged product.

 

[seabass07]

Months. Years? Don't think it will go bad in a sealed clean keg. Might eat away at the rubber seals eventually though.

 

[crusader1612]

Leaving Starsan too long, tends to leave film on the surface. almost greasy, and whiule you dont fear the foam etc. i wouldn't leave a keg like that full of starsam for more than 12 hours.
leaving liquid residue, isn't too much of an issue.

 

[seabass07]

Never had that happen on any surface other than vinyl tubing.

 

[cyanmonkey]

I believe Starsan will eventually turn alkaline unless made with distilled or very soft water. My water is really high in bicarbonate and starsan goes bad within half an hour, so I usually just keep a spray bottle with distilled water in it around.

But +1 to eventually getting scummy on tubing.

 

[Spartan1979]

Leaving Starsan too long, tends to leave film on the surface. almost greasy, and whiule you dont fear the foam etc. i wouldn't leave a keg like that full of starsam for more than 12 hours.
leaving liquid residue, isn't too much of an issue.

If you make the StarSan with distilled or RO water this isn't a problem. I've had a keg with StarSan in it for a couple of years now (not all the same batch).