[KellerBrauer]

If you mix StarSan with RO or distilled water it will last a long time. If you mix it with tap water you may find that it only lasts a day before it becomes cloudy and slimy. StarSan is an acid and if you mix it with water that has high alkalinity it gets neutralized. If you want to see whether it is still good you can measure the pH. If it is still below ~3.5 it is probably OK, but even then its ability to coat surfaces degrades with time.

All good points.  I would agree that it depends on the water.  I use softened water in a 5 gallon bucket and add 2oz. StarSan.  3-4 months later, the mixture is still crystal clear.  I know it’s still effective because when I dump the bucket, I get a monster foam up in the sink.  My water has a pH of 7.2 as I recall.  Next time I want
to change it, I’ll measure the pH, as you suggest.

[goose]

If you mix Starsan with distilled water and keep it in a covered container, it will stay good for a long time.

Agreed.  I use Saniclean, which is the non-foaming version of StarSan, mix it in R.O. water (or distilled water) and store it in a Rubbermaid cooler.  I can keep it for several months before discarding it.  Just measure the pH occasionally to make sure it is below 3 and you are fine.
The only disadvantage of using Saniclean is that you have to use a bit more of it.  I put 55 ml (1.9 oz) in 5 gallons of R.O. water (per Fiver Star's recommendations).  But the lack of foaming makes it worth the extra expense.

[KellerBrauer]

If you mix StarSan with RO or distilled water it will last a long time. If you mix it with tap water you may find that it only lasts a day before it becomes cloudy and slimy. StarSan is an acid and if you mix it with water that has high alkalinity it gets neutralized. If you want to see whether it is still good you can measure the pH. If it is still below ~3.5 it is probably OK, but even then its ability to coat surfaces degrades with time.

All good points.  I would agree that it depends on the water.  I use softened water in a 5 gallon bucket and add 2oz. StarSan.  3-4 months later, the mixture is still crystal clear.  I know it’s still effective because when I dump the bucket, I get a monster foam up in the sink.  My water has a pH of 7.2 as I recall.  Next time I want
to change it, I’ll measure the pH, as you suggest.

Out of pure curiosity, I decided to measure my sanitation bucket using my pH meter that was calibrated about 2 weeks ago and my StarSan solution pH is 2.17 and it’s about 2 months old.

Using RO, or Distilled water might be a good practice, but I’m not convinced it’s necessary for good sanitation.

[Bob357]

If you mix StarSan with RO or distilled water it will last a long time. If you mix it with tap water you may find that it only lasts a day before it becomes cloudy and slimy. StarSan is an acid and if you mix it with water that has high alkalinity it gets neutralized. If you want to see whether it is still good you can measure the pH. If it is still below ~3.5 it is probably OK, but even then its ability to coat surfaces degrades with time.

All good points.  I would agree that it depends on the water.  I use softened water in a 5 gallon bucket and add 2oz. StarSan.  3-4 months later, the mixture is still crystal clear.  I know it’s still effective because when I dump the bucket, I get a monster foam up in the sink.  My water has a pH of 7.2 as I recall.  Next time I want
to change it, I’ll measure the pH, as you suggest.

Out of pure curiosity, I decided to measure my sanitation bucket using my pH meter that was calibrated about 2 weeks ago and my StarSan solution pH is 2.17 and it’s about 2 months old.

Using RO, or Distilled water might be a good practice, but I’m not convinced it’s necessary for good sanitation.

How long the solution remains effective depends on the water used.

[CounterPressure]

I was going to clean a few kegs tonight so I took a look at my Saniclean and it had barnacles growing in the bottom of it, which I wasn't surprised at after 3 weeks. I whipped it up when I brewed a few weeks ago and didn't mess with it this past weekend. It was still pretty clean after 2 weeks but not so much after 3.  This was just tap water but it does go through a water softener here at the house. Just for fun I thought I would throw the pH meter in it, figuring for sure it was spent if there was all that solids growing in the bottom. Nope, pH was 2.3 right on the money. I've never checked it with a new bucket so I don't know what that would be. And I made a bucket of star san tonight instead so I don't think it would be a fair comparison.

I just thought it was interesting that the pH was perfectly fine, and it might work the same as it always did. I wasn't interested in finding out. It certainly didn't look like something I wanted to sanitize anything with.

[hopfenundmalz]

I was going to clean a few kegs tonight so I took a look at my Saniclean and it had barnacles growing in the bottom of it, which I wasn't surprised at after 3 weeks. I whipped it up when I brewed a few weeks ago and didn't mess with it this past weekend. It was still pretty clean after 2 weeks but not so much after 3.  This was just tap water but it does go through a water softener here at the house. Just for fun I thought I would throw the pH meter in it, figuring for sure it was spent if there was all that solids growing in the bottom. Nope, pH was 2.3 right on the money. I've never checked it with a new bucket so I don't know what that would be. And I made a bucket of star san tonight instead so I don't think it would be a fair comparison.

I just thought it was interesting that the pH was perfectly fine, and it might work the same as it always did. I wasn't interested in finding out. It certainly didn't look like something I wanted to sanitize anything with.

I hear barnacles are tasty, will the opportunity to try some soon.

[neuse]

Was it sitting out uncovered? Still, barnacles - wow. I've never found anything nasty in my Star San solution that's been sealed for a couple of months - or more.

[CounterPressure]

I always start with warm water from the faucet. You know the three T's, time temperature and turbulence. But no, it just had suspended solids of some sort of gelatinous stuff like it always gets. Eventually it gets cloudy in the bottom of the bucket after a period of time. It had a lid on but just sitting on top, I don't press it on to seal it. Maybe if you use distilled or RO water you don't get that kind of problem. I'm not wasting my time or money with that stuff, Star San is entirely too cheap for me too waste my time carrying gallons of water to make sanitizer. I wash and rinse everything in the very same water so all I want to do is make sure there's no residual bacteria sitting on stuff when I'm done.

The Barnacles part is just an exaggeration for humor.

[neuse]

I make up a gallon of Star San when I get low. My tap water is slightly hard and makes it cloudy right away, so I buy distilled water in 1 gallon jugs. The water costs way more than the Star San at about $1.20 per gallon. Since it's kind of expensive, I keep it sealed, and it lasts for months.

[nvshooter2276]

.. .. .. I buy distilled water in 1-gallon jugs...

Would WalMart's Purified Drinking Water do well for mixing StarSan? I have several gallons of it for brewing. I figgered it would be better than my tap water, even after running it through my on-faucet PUR filter. After filtering my water has no chlorine smell, and tastes just as good as the water from my dad's $7000 RO system. The water at my family home in Virginia comes from 108 feet down and is hard as a bolt. I doubt I could tell the difference in a blindfolded taste-test...

I might be swinging through Walmart, today. I'll grab a few DW bottles; I can always use it in my CPAP machine...

[Richard]

I make up a gallon of Star San when I get low. My tap water is slightly hard and makes it cloudy right away, so I buy distilled water in 1 gallon jugs. The water costs way more than the Star San at about $1.20 per gallon. Since it's kind of expensive, I keep it sealed, and it lasts for months.

$1.20 per gallon of distilled water brings back fond memories to me. The price here is closer to twice that now. Here is a thread I started last year with the subject "StarSan is cheaper than (distilled) water"
https://www.homebrewersassociation.org/forum/index.php?topic=39486.msg484766#msg484766

[nvshooter2276]

Would WalMart's Purified Drinking Water do well for mixing StarSan?

Still looking for an answer to this question...

[Richard]

Would WalMart's Purified Drinking Water do well for mixing StarSan?

Still looking for an answer to this question...

I have no idea what the specifications are for Walmart's Purified Drinking Water. It is probably fine, but without having some hard data on it nobody is going to be able to answer the question.

[John M]

Would WalMart's Purified Drinking Water do well for mixing StarSan?

Still looking for an answer to this question...

I have no idea what the specifications are for Walmart's Purified Drinking Water. It is probably fine, but without having some hard data on it nobody is going to be able to answer the question.

I've brewed many of batches using water collected from my local Walmart's RO system. It was always reliably below 5 ppm TDS. I imagine that could vary from store to store, depending on how well they maintain their system.

[neuse]

Would WalMart's Purified Drinking Water do well for mixing StarSan?

Still looking for an answer to this question...

I have no idea what the specifications are for Walmart's Purified Drinking Water. It is probably fine, but without having some hard data on it nobody is going to be able to answer the question.

I've brewed many of batches using water collected from my local Walmart's RO system. It was always reliably below 5 ppm TDS. I imagine that could vary from store to store, depending on how well they maintain their system.

I found it on their website. It doesn't look like RO water. Description includes "you can be confident that it's pure water and nothing else." But I wouldn't take that literally.
Edit: Here is a link: https://www.walmart.com/ip/Great-Value-Purified-Drinking-Water-16-9-fl-oz-Bottles-40-Count/992524020?athbdg=L1200&from=/search