[ajk]

This thread has a quote from a StarSan employee stating the solution must have a pH below 3.5 AND be clear.  Cloudiness indicates the surfactant has reacted with minerals in the water and become ineffective.  The surfactant renders more permeable the cell walls of the unwanted flora, and the low pH then kills them.

[mugwort]

Thanks everyone for the input, especially ajk for that link to the thread with the additional Star San info.

In this case of an immediate, drastic change in the time-to-clouding observed from one bottle of SS to the next, all I can suppose there is some appreciable difference between the two batches of Star San that I own.  How and why they came to be different is unknown.

What I do know now is that I need to change my usage practices.  I'll immediately start with the suggestion of using distilled water to mix up solutions that go into my spray bottles or in any situation in which I wish to keep the mix beyond a day.

Cheers and happy sanitizing!

[narvin]

This thread has a quote from a StarSan employee stating the solution must have a pH below 3.5 AND be clear.  Cloudiness indicates the surfactant has reacted with minerals in the water and become ineffective.  The surfactant renders more permeable the cell walls of the unwanted flora, and the low pH then kills them.

If that's true, I might consider switching back to Iodophor for everything.  I sanitize my kegs with star san and push it out with CO2 to purge all the oxygen, and by the second keg it's already cloudy.  I have relatively soft water (Ca 28, HCO3 59), and I'm not going to buy 5 gallons of distilled water just for sanitizing.

[tygo]

This thread has a quote from a StarSan employee stating the solution must have a pH below 3.5 AND be clear.  Cloudiness indicates the surfactant has reacted with minerals in the water and become ineffective.  The surfactant renders more permeable the cell walls of the unwanted flora, and the low pH then kills them.

If that's true, I might consider switching back to Iodophor for everything.  I sanitize my kegs with star san and push it out with CO2 to purge all the oxygen, and by the second keg it's already cloudy.  I have relatively soft water (Ca 28, HCO3 59), and I'm not going to buy 5 gallons of distilled water just for sanitizing.

That five gallons with distilled will last for a long time though if you keep it around.  I do the same thing and always have one keg filled with starsan.

[ajk]

This thread has a quote from a StarSan employee stating the solution must have a pH below 3.5 AND be clear.  Cloudiness indicates the surfactant has reacted with minerals in the water and become ineffective.  The surfactant renders more permeable the cell walls of the unwanted flora, and the low pH then kills them.

If that's true, I might consider switching back to Iodophor for everything.  I sanitize my kegs with star san and push it out with CO2 to purge all the oxygen, and by the second keg it's already cloudy.  I have relatively soft water (Ca 28, HCO3 59), and I'm not going to buy 5 gallons of distilled water just for sanitizing.

I use "softened" water (from my Culligan system).  I keep the mixed StarSan solution in a corny keg, and it lasts for anywhere from weeks to months.  A solution made with distilled water would surely last even longer.

[quattlebaum]

This is my H2o profile in Idaho Falls. In the early days when i didnt pay attention to my H20 brews were just off. My starsan immediately clouded when poured into my tap water. Hell $2 for RO water has made a huge difference. It last 3 to 4 months for me and i brew often.
Calcium   66
Sulfate S04-s   12
Magnesium   20
Sodium   27
Chloride   18
Hardness   262
Alkalinity   224
Idaho Falls PH 8.1

[Jimmy K]

When I make it with distilled water it stays cloud-free as you'd expect.  It just struck me interesting that when I make it with tap water it clouds up much much quicker than before, and just like mugwort this seemed to have happened coincidentally after using a new 32oz bottle.

Does StarSan lose its acidity over time in storage and perhaps the stuff in my old bottle was "old"?  It takes me a very long time to go through a 32oz bottle.

I've never heard of an acid that looses it's acidity during storage.

[LWHOUSE]

I know this is an old thread, but I have noticed the same thing.  My Star San solution with carbon filtered tap water  in forest, Virginia used to stay clear for months.  Starting in early 2013 I noticed it would be cloudy within days.  I measure the pH and I continued using the Star San solution as long as the pH did not go above pH 2.7.  I did shorten the time that I keep the solution, but I do not know if it was necessary.  I never had any problems with contamination.

My conclusion is something did change with so many from different areas reporting the same thing.

[denny]

FWIW, mixed with distilled water, I haven't seen this.

[dkfick]

With tap water my Star San will cloud up pretty much instantly... Within an hour for sure.  I use RO water (assuming I wasn't too lazy and have some made up...) It lasts for months with RO water.

I ran an experiment a while back with 2 mason jars of star san (made with RO water).  One covered and one uncovered. The pH of both remained about the same for quite awhile. Though as the uncovered one started to have water evaporate the pH dropped.  They both started at a pH of 2.14 and 5 months later the volume of the open jar reduced by about 7/8ths and had a pH of 1.87 and the sealed one had a pH of 2.24.

I have noticed on large batches I make the pH does rise and I believe this is due to the fact that you're sticking stuff in there all the time which is neutralizing some of the acid.

[Stevie]

I use RO and keep it until the level drops below a usable amount or it gets dirty.

[ynotbrusum]

Softened water (ion exchange as noted by Martin) with Star San stays good for me quite a while, but I have gone to changing it out after a week or two, just to be safe.  I don't have any problem with that.  I occasionally go with distilled, and keep it around longer in smaller quantities like a gallon.