I carbonated my star-san and now it's cloudy

[trigger]

So, I accidentally put my star-san keg on 35 psi for the last few days. Tonight I went to pour off the sediment and get a sample (I thought it was a recently kegged IPA). When the starsan came out it foamed big, but I left the glass out on the counter while I gassed up the IPA and did some other beer chores, intending to use it for "spot" sanitation. The liquid in the bottom is seriously cloudy, though. I had just completely disassembled and cleaned this keg a couple weeks ago and filled it with 5 gal of fresh water and 1/2 oz of star-san.

Has anyone else had this happen? Seing as how it's an acid sanitizer, I can't come up with a rxn between the components of starsan and carbonic acid to explain a precipitate. Besides, LeChatelier's principle should have shifted the carbonic acid equilibrium to the left, decreasing [H2CO3] unless there's something else going on that I'm missing. Also, I'm in Portland, so our tap water is very low, like distilled almost.

 

[Nuggethead]

Huh

 

[trigger]

Haha, I guess that was a bit rambly. Basically I'm wondering if it's the carbonation that made it cloudy, and if so why? I suppose I could run another experiment (rinse the keg very well, mix up new star-san and recarbonate) but I'd rather not waste the gas and sanitizer if someone else knows why this happened. If it's not the carbonation I'm going to have to look for another cause, as this is the first time I've had brand new star-san go cloudy on me.

 

[Hermit]

My water is hard. It turns my starsan cloudy. When I use it in an air lock the co2 bubbling through clears it up.

 

[Seven]

How did it taste?

 

[milesvdustin]

How did it taste?

Sanitary!

 

[Mista_Sparkle]

my star san ends up cloudy as well, even when first mixed. My water is stupid hard though.

but yeah, I would expect hard water to remain clear of it is an acid...

sorry no solution...
or is it?

 

[trigger]

Yea, this actually started clear, as it usually does. After it was sitting for a few days under CO2 it turned cloudy.

If your star-san is cloudy from hard water i'd expect it to clear if you carbonated, though, as the pH decreases. That's what's got me stumped. I started with very soft water that made clear sanitizer, and now it's cloudy.

 

[Houblon]

I use starsan & distilled water and store it in a keg under gas & push it into each new keg.
Gas doesn't make it cloudy

 

[Pick]

My starsan is cloudy, even when first mixed up. I have used it for months and have tested the PH and it is still good.

 

[arch1tect]

It's not supposed to be cloudy?

 

[cactusgarrett]

I believe it's a pH thing.

 

[Seven]

The creator of star san says hard water will cause the sanitizing mixture to cloud. He recommended using de-ionized water from the grocery store instead of hard water.

Link to podcast is here. He mentions this about 37-mins into the show: Sanitizing with Star San

Our house has a water softener and I found my star san mixtures do not cloud unless it's more than 48-hours old.

 

[Homercidal]

My starsan turns cloudy right away if I mix with tap water. Too much hardness. If I use distilled water it can sit in the jug for MONTHS and I have to shake it to see if it's water or sanitizer (Hint: Star San foams!)

I'm betting that it's just the hardness. Carbon Dioxide would add a small amount of acid, and I doubt that would cause it to cloud up.

 

[malnutriton]

I always have starsan on tap! I use distilled H2o and carbonate to like 4 volumes of co2...bam! I feel the carbonation helps it to work more efficiently.

 

[remilard]

My starsan turns cloudy right away if I mix with tap water. Too much hardness. If I use distilled water it can sit in the jug for MONTHS and I have to shake it to see if it's water or sanitizer (Hint: Star San foams!)

I'm betting that it's just the hardness. Carbon Dioxide would add a small amount of acid, and I doubt that would cause it to cloud up.

When I mix up a gallon of star-san I write star-san and the date on it. I throw the whole thing away (or more likely use it as a blowoff container and then discard) at about the 2 month point.

 

[ksbrain]

I always wonder how cloudy is too cloudy. I have some distilled water starsan mixture, and it's sort of cloudy... I don't think my crappy pH papers go into starsan range, and I'm just not scientist enough to manage the whole electronic pH meter thing.