Author Topic: Star San goes really bad?  (Read 1690 times)

Offline gsandel

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Star San goes really bad?
« on: April 02, 2012, 11:27:25 AM »
I didn't see this, so am reporting second hand, but want to know if anyone has clue as to what is going on.

I had stored Star San in my emptied/cleaned keg under a little co2 pressure to ensure seal (although I may have not remembered to use CO2, so it could have been air.  It sounds like a sound business practice from reading this forum.  When my brother opened the keg expecting to dump and fill, the keg smelled sour and the star san solution inside was skim milk white.

Of course and thankfully, he stopped, rinsed thoroughly with hot water and re-sanitized.  To my knowledge, the star san was mixed at an appropriate solution with clean (probably hot at the time) water from the tap.

Does anyone know what conspired here?  Only things I can think of are reaction to something in Denver's tap water or a reaction with CO2 or some sort of oxidation.  Does Star San go really bad like this?  Is there anything else I could unknowingly have done to make this happen?

Does long term exposure to star san (bad or good) do any damage to non stainless parts (o-rings, connectors, etc.)?


You wouldn't believe the things I've seen...

Offline bluesman

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Re: Star San goes really bad?
« Reply #1 on: April 02, 2012, 11:35:07 AM »
You probably had some organic material in the keg that reacted with the starsan solution to raise the pH and turn it cloudy. Starsan's active ingredient is phosphoric acid which when in solution with water is at a pH of 3.0 or less. It won't corrode stainless at this pH level. It is safe to remain in contact with your equipment (SS) for extended periods of time.
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Offline jmcamerlengo

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Re: Star San goes really bad?
« Reply #2 on: April 02, 2012, 12:49:04 PM »
Yeh especially if you used hot tap water. Deposits can build up quite a bit more in hot tap water opposed to cold. Star San reacts with metals and whatnot in the water and thats what degrades it.  Using distilled water in a covered and sealed vessel Star San can essentially last forever, providing of course that the vessel is CLEAN before filling. As Ron mentioned, organic deposits in the keg can also cause degradation.
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Offline richardt

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Re: Star San goes really bad?
« Reply #3 on: April 02, 2012, 01:23:59 PM »
For the "keep the pH < 3" reason mentioned earlier, use Distilled or Reverse Osmosis (RO) water to make up your StarSan solution and store it in those cheap 5 gallon buckets w/ a lid that you can get from Home Depot.  Lasts practically forever, but I make a good practice of only using it to sanitize when the desired item has been thoroughly cleaned and rinsed first.  Most tap water has some residual alkalinity (bicarbonate) that will drive up the pH of the solution. 

Nonetheless, it is sound practice to dispose of the aging StarSan solution and make a fresh batch of StarSan solution periodically.