How long does santizer last?

[teddyearp]

Just curious. I use StarSan. After making a batch in my sink for doing a big rinse for bottling and making a new batch, I usually take off some into a bowl/bucket.

As long as I use it just to rinse and not clean, how long could it last?

 

[Robert65]

If mixed with deionized water, it can keep an indefinite amount of time in a covered container. It will remain effective as long as the pH remains below 3.5. If pH rises to 3.5, discard and mix a fresh batch. If not mixed with deionized water, you should probably check pH even on the initial mixing.

 

[gromitdj]

It really depends on a couple of factors, including the composition of the water used to dilute it. The old addage is that it's good as long as it's clear and not cloudy. The only way to know for sure is to check the pH of the solution as mention above.

 

[balrog]

I toss mine when it smells, has floating bits, or pH test strips say it's below 3.5 pH.
If you have high alkaline water, mixing StarSan fresh will be cloudy, but again, as long as it is acidic, below 3.5, the little bacterial baddies will be most significantly unhappy.

 

[Robert65]

Yes, the cloudiness is usually just precipitation of phosphate salts as the phosphoric acid meets minerals in the water, if present; though if you mixed a clear solution with deionized water, cloudiness is a dead giveaway it's no good. The phosphoric acid is not the active killer, that's the dodecylbenzenesulfonic acid. So check pH. I should have noted earlier, I toss mine when there's gross stuff on the bottom of the bucket, too. It also seems to get slimier and more unpleasant smelling as it ages, whatever that means.