How long is star san effective for after initial mix

[smellgoats]

I have a leftover gallon from a batch made 2 weeks ago, also some in a spray bottle. Dump and start over or still trust it?

 

[Hugh_Jass]

As long as the pH is below 3, it's effective. Ignore the cloudiness.

I use the same SS for months with no ill effects.

 

[micahshaw]

Ya, I just look at it and decide if the pH is still 3. Seriously, that's how I do it, I just look at it, and at some point (usually about 2 months or so) when a notice an increasing amount of stuff in it, I get worried and throw it out. So far, no infections. But I would love some better advice on how to tell if the pH is ok. From my brief searches, it looked like using test steps was going to be more expensive than just making new solution ever month or two. How are other people really deciding if it is time to change the Start San?

 

[TomSD]

Diluted into bottled or RO water I keep mine indefinitely in a keg making/adding more as needed. I do test it on occasion though, a lot less than I used to, and it has never come back "bad". If you don't wash and sanitize in the same step you can reuse the stuff pretty much indefinitely.

I run the stuff over my equipment straight from the keg and let it run off into a bucket. I pour some into my pots/carboys/etc and swish it around then dump it back into the bucket. When I'm done it all goes back into the keg to be reused. The biggest waste when I am brewing is filling the pitcher for my blow offs.

 

[ajwillys]

Like this:
http://www.austinhomebrew.com/product_info.php?products_id=1013

EDIT: I see someone mentioned test strips. This is super easy and cheap. I check it in about 10 seconds. I make up 2.5 gallons at a time and put it in a cast-off bottling bucket. I usually throw it away when it starts getting floaties, which tends to happen since I just soak everything (well, the stuff that needs it) in there while brewing. I probably replace it every other month or so.

 

[Brew-ta-sauraus]

If you mix it with distilled water in a spray bottle it will last months and months.