Blowoff liquid(starsan) suddenly became transparent

[Sequoiacider]

I noticed that the Starsan solution I am using in my blowoff reservoir suddenly went from the normal cloudy appearance to transparent from one day to the next. I typically use airlocks rather than blowoffs, but even in airlocks I am used to the solution remaining cloudy throughout the entire process.
I don't think I have any reason to be concerned, especially since active fermentation is still going on and I don't expect to do anything that would cause suckback.

Is there any reason to be concerned? Should I replace the solution in my blowoff with fresh Starsan solution?

 

[Robert65]

Star San is supposed to be clear. Cloudiness is a visual indicator that it has lost effectiveness. It can also be caused by mixing the solution with water which is not deionized, in which case it may or may not still be within the effective pH range, but without the visual indicator the only way to know is by testing pH. How it can possibly go from cloudy to clear is a mystery.

 

[RPh_Guy]

Cloudiness is a visual indicator that it has lost effectiveness.

Scientific source? Or myth?

I test pH of my cloudy Star San and it's still in the effective range.
My Star San gets cloudy even with RO water.

suddenly went from the normal cloudy appearance to transparent from one day to the next.

This actually happens to me every time. I guess it's the dissolved CO2 (carbonic acid) that somehow increases solubility of whatever precipitate causes the cloudiness.

 

[Sequoiacider]

Interesting. I typically mix Starsan with my tap water and I am used to it having a cloudy appearance. From what you are saying, it sounds like my normal processes may have a glaring flaw, but I have never experienced any problems that would indicate ineffective sanitation procedures.

I'll check the pH of my tap when I am at home. I cant imagine buying distilled or deionized water in the quantities necessary, as that would be cost prohibitive. I typically mix up 5 gallons of solution anytime I am using it.

I understand that my municipality uses a bit more chlorine that other areas. Could that be causing the cloudiness that I am used to seeing? If so, would that be of concern considering the fact that chlorine is also a sanitizing agent?

 

[Sequoiacider]

RPh: Thanks. Your response came in as I was typing my reply. It sounds like what I am seeing is normal.

 

[RPh_Guy]

I'll check the pH of my tap when I am at home.

The water pH is meaningless. Test the pH of your Star San solution. Under 3 means it's effective.

 

[Sequoiacider]

RPh: You are becoming my best friend! Thanks for the very helpful info.

 

[Robert65]

I mix a 5 gallon bucket with RO water and it will keep indefinitely. Minerals in the water are indeed what causes the cloudiness when mixing with tap water, and as RPh_Guy says, it's fine below pH 3.0. If mixed with RO or DI water, it will only become cloudy when PA concentration drops, and pH rises above this level, at which point it's time to discard and mix a new bucket (even if it's still clear, it is prudent to periodically check pH in the bucket.) It would be interesting as a matter of curiosity if dissolved CO2 (carbonic acid) from fermentation was rendering the impurities in the water more soluble, but it wouldn't be of practical importance. pH is the important thing. I've had it turn cloudy during fermentation, never seen it go the other way.

 

[RPh_Guy]

Minerals in the water are indeed what causes the cloudiness when mixing with tap water

Precipitated phosphate salts, yes? It's a little weird my RO water Star San gets cloudy.

We're on the same page. Just to clarify:
Star San doesn't suddenly become cloudy over pH 3, so it's not the best indication of whether it's effective. PH testing is the only way to be sure.

It would be interesting as a matter of curiosity if dissolved CO2 (carbonic acid) from fermentation was rendering the impurities in the water more soluble,

Yeah. My guess is that the pH drop from the carbonic acid increases the salt solubility.

 

[Robert65]

^^^^^
Right. As I say, it's prudent to regularly monitor pH in a bucket load. But it's handy that if it's sat for a while and starts to look a bit less clear, you immediately know it's time to replace. And I doubt that you could keep a batch mixed with tap water for a very long time, because of said precipitation of phosphate salts depleting the PA. I think Five Star recommends making it up fresh every day. So it is a money saver to use RO and get a degree of shelf stability.

 

[Sequoiacider]

I'm stoked. Y'all are awesome. It sounds like as long as the pH of my solution is proper at 3.0 or less then I am good. I will monitor the pH of the solution and replace as needed. It also sounds like investing in a RO filter would be a good idea for me (for this and other reasons).

 

[RPh_Guy]

I refill my own containers with RO water at Wal-Mart from the machine for $0.39/gallon. ... I make Star San in a spray bottle 800mL RO water with 1/4tsp Star San. Super cheap.
I imagine you're using it to purge kegs, otherwise you wouldn't make so much at a time?

because of said precipitation of phosphate salts depleting the PA

Depleting the PA isn't problematic in and of itself. The DBSA is the active ingredient, so as long as the pH is fine then it's good.

 

[Robert65]

[1] I imagine you're using it to purge kegs, otherwise you wouldn't make so much at a time?


[2] Depleting the PA isn't problematic in and of itself. The DBSA is the active ingredient, so as long as the pH is fine then it's good.

1) No, I don't trust Star San as far as I can throw a bucket of it really, iodophor is my primary sanitizer. (Not much shelf life once made up but cheap.) I use Star San as a spray bottle sanitizer for applications where this is convenient, but since it does keep, I make it by the bucket. Really an old habit from when my use of it was more general. Now I think about it, it's kind of pointless and I may just make it a bottle at a time. My RO unit runs a gallon in 15-18 minutes, so I could do this at a moment's notice.

(2) Thanks for the explanation!

To the OP: An RO unit is a nice thing to have. For many reasons. Mixing these sorts of chemicals, rinsing pH meters, calibrating refractometers, and, oh yeah, brewing water too!