I keep StarSan in a spray bottle for easier sanitizing during brew day.

How long does the StarSan last in that bottle? Is it good forever?

4 Answers 4


Just after posting the question I found the Tech Sheet on Five Star's website. It says that the sanitizer is good so long as the pH remains below 3. Since I'm keeping it in a spray bottle with distilled water it shouldn't ever get above 3.


I've heard people say they reuse it until it starts to turn cloudy, but I'm more apt to use the pH rule, since it lasts longer.

  • 1
    Do you actually test the pH?
    – sgwill
    Commented Nov 11, 2010 at 14:07
  • 2
    Honestly, no. I just dump it every couple times I brew. Except one time I found a dead bird floating in the star san bucket, so I obviously dumped that on.
    – PMV
    Commented Nov 11, 2010 at 14:24
  • 1
    pH test strips are both cheap and readily available, and plenty accurate for this use. That said, I'm not sure that I'm anal-retentive enough to test it every time, either.
    – Herb
    Commented Nov 11, 2010 at 15:24
  • The pH rule is the best guide - my starsan turns cloudy immediately, but it's still effective. I keep in an airtight container and test every couple of weeks, and again if it gets a bit soiled.
    – mdma
    Commented Jan 19, 2012 at 15:37

StarSan along with many of the other no rinse / food safe sanitizers are primarily just acid solutions. Of which the largest proportion is Phosphoric Acid, with some other stabilizers and minor acids depending on the make. These won’t naturally decay in any medium time frame and as long as it stays acidic I.e its pH is maintained in the acidic range < 3.

What will affect it is:

  1. The factor at which you dilute it, if you add too much water it looses its acidity and will not be effective.

  2. What you dilute it with, if the water in your area is highly alkaline (brak) then you have the potential to, even at normal dilution rates to cause the solution to no longer be acidic, meaning it’s ineffective.

Case in point. It will stay as potent as the day you made it given (1) and (2) and no other outside dilution takes place.


As opposed to Perisan, Starsan contains no peroxide component. This gives it a much longer shelf life. Keep it in an airtight container in a dark cupboard and it will probably last indefinitely. As the manual says, when in doubt check the pH.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.