How long will star stan keep when used?

So I am trying to stretch my star san as far as possible. How long after mixed and used will it keep if covered.

For instance, can I mix a 2 gallon batch for brew day equipment, pour left overs into my secondary (covered) until transfer, then transfer it from secondary to bottling bucket (cover), and store it there until bottling day.

Then (being greedy) can I trasnfer it from bottling bucket back to my clean primary fermenter and start over with it for next batch?

Or, alternatively, can I just make a batch that I store in a brew pail and use when ever I want?

I use distilled water and make up 3 gallon batches. I change it every 2.5 to 3 months, which is early. It depends on your water and the ph of the star-san. I believe as long as it stays under 3 you're good.

Oh! Did a search in some other sections and found some useful info! Looks like if it is still clear it is A OK.

What causes Star San to cloud? Mine turns cloudy within 5 minutes? I make a new batch every time I use some but I becoming concerned that something in my water is neutralizing it.

There are multiple things that can make it cloudy, make sure the pH is below whatever threshold is necessary, and you're probably fine.

The Brewing Network did a Session show with the inventor of Star San on 3-19-06.

wildwest450 said:

I use distilled water and make up 3 gallon batches. I change it every 2.5 to 3 months, which is early. It depends on your water and the ph of the star-san. I believe as long as it stays under 3 you're good.

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I do the exact same thing here.... except I don't just toss it every 3 months... I will top it up once or twice with a fresh gallon of distilled water and star san.

I also keep a spray bottle handy and spritz the bucket insides, this stretches it's use considerably.

With tap water my solution is turning cloudy within 5 minutes too. Distilled water is your friend. $0.79 a gallon or $0.99 at the market when grocery shopping.

I make up a 5 gal batch every other month or so. I fill a spray bottle from every new batch also.

I don't pour it all down the drain when making a new batch...I use it to mop the floor. The floor's not sanitized for long, but at least it's cleaning up any grain dust and such.

hard water can make it instantly cloudy, but the pH is still spot on. I have some pH test strips that I use to check my solution. even with my hard water, it'll keep for a month or longer.

I must have good water, I've used the same batch of Star-san for the last 4 batches, although I did "freshen" it up with a potent 1 gallon mixture 2 batches ago (about a month ago). Whenever I feel like it, I test with pH strips, and it has always been under 3. I keep it cool and covered.

My current 5 gal batch of Star-San was probably made in May.
It's been cloudy since I made it, but as long as it remains under pH 3.5, I consider it just fine.

Each batch costs like a buck, so I mix up a new 5 gallon bucket every other weekend, usually.

After two or three weeks of use I often see some gross stuff accumulating at the bottom of the bucket. Even if the solution is still at the right pH, it just feels right to mix up a new batch when that happens.

i would recommend the brew strong episode on sanitation (5 jan 09) where they interview Jon Herskgovits of five star. I believe Jon says something about keeping your star san solution at 3.5 ph and ensure that it isn't cloudy.

he says a few other things, but i don't want to ruin the whole show for you.