Starsan - How long does it last and is it OK to leave tubing soaking?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk:

Brian66

Well-Known Member
Joined
May 25, 2020
Messages
124
Reaction score
61
Location
New Jersey
I use starsan for my sanitizing. On brew day I'll make a 5 gallon bucket of it to use throughout the day. I usually keep that bucket of sanitizer for sanitizing in the following days/weeks. I've noticed that after awhile it turns cloudy - is it still effective at this point? Also, I've left tubing in the sanitizer and then forgotten about it. The tubing gets white/cloudy color to it - is the tubing still ok to use? Has the sanitizer done any damage to the tubing when this happens?
 
Joined
Feb 24, 2013
Messages
1,759
Reaction score
2,023
Location
New Brighton
Star San is usable until the PH rises to above about 3.5. When it gets cloudy it is a sign that it probably has. Making it with low mineral water can help. RO or distilled are both low mineral.

I'm not as sure about the tubing. I've had that happen before. I think if you let it dry out it returns to almost normal color after a while. Hopefully someone else will have a more informed answer on this for you.
 

mashpaddled

Well-Known Member
Joined
Sep 25, 2018
Messages
758
Reaction score
520
Location
Denver, CO
I've had this happen to a lot of my tubing. You can wash off the cloudy reside, resanitize, and use it. I've never had problems.
 

skeeterman

Member
Joined
Jan 13, 2015
Messages
23
Reaction score
8
Location
pierre
I use starsan for my sanitizing. On brew day I'll make a 5 gallon bucket of it to use throughout the day. I usually keep that bucket of sanitizer for sanitizing in the following days/weeks. I've noticed that after awhile it turns cloudy - is it still effective at this point? Also, I've left tubing in the sanitizer and then forgotten about it. The tubing gets white/cloudy color to it - is the tubing still ok to use? Has the sanitizer done any damage to the tubing when this happens?
I was told that as long as it still bubbles or foams when used that it is fine.
 

hotbeer

Opinionated Newb
HBT Supporter
Joined
Mar 10, 2021
Messages
1,134
Reaction score
790
Vinyl tubing will get white from just staying completely submerged in water for several days. Hours if the water is kept hot. It does weaken the tubing. Maybe not permanently if left to dry out for several days.

Personally I see no reason to keep mixed sanitizer for more than the day I use it. Certainly keeping stuff in it till the next brew day with the idea you are making or keeping that stuff more sanitary is probably marginal at best.
 

Broken Crow

Ale's what cures 'ya
Joined
Oct 12, 2020
Messages
227
Reaction score
258
The silicon tubing always seems fine..if anything the starsan seems to remove some of the staining, vinyl is, in my own experience much different. Since the first time I used some vinyl tubing for blow-off, leaving one end in a jar of starsan and watching it turn milky-white, I've been worried about it's potential reactivity. Although I do use vinyl tubing for transfers and carbing, I'm slowly in the process of replacing them with eva barrier and silicon. I've noticed that the tubing I've left in starsan for weeks, ages a lot faster afterwards and when I've measured the wall thickness and compared it to tube from the same batch that has only seen short sanitizing periods immersed, I've found the walls have expanded and I just don't trust it to touch any of my beer now. Maybe that's just me.
 

hotbeer

Opinionated Newb
HBT Supporter
Joined
Mar 10, 2021
Messages
1,134
Reaction score
790
Those of us who keg and do CO2-pushed Star San purging appreciate having ~6 gallons of sanitizer handy...

Cheers!

Exactly - plus I sanitize hop socks for dry hopping.
I'm all for you doing what works for you. Not saving it works for me.

The question of how long StarSan is effective after being mixed with water comes up often. And the fact that how long it lasts depends on things unique to each situation. So for me, I see no reason to not use fresh mix every time and avoid the potential pitfalls.

Still how much more effort is it to fill a container and add the measured amount of sanitizer to it? My laundry sink faucet fills a five gallon bucket in 40 seconds. Another gallon a few more seconds.

As for hop sacks, they only need a few minutes in sanitizer. Assuming of course they are clean when they are put in.
 

day_trippr

"This Space For Rent"
Joined
May 31, 2011
Messages
38,327
Reaction score
21,420
Location
Stow, MA
If one has lousy water for the purpose (lots of minerals particularly carbonates) I could see mixing up a batch for just a day or two then dumping it. It's not that pricey after all. Otoh, I use my RO water (tds <8) when I mix up a batch of Star San, and it remains viable for many, many months, crystal clear with pH hanging around 2.something the whole time. No sense dumping it if it's still good to go :)

Back on topic, I never leave anything soaking in Star San for more than a minute or two. No need to - and plastics and rubbers generally don't enjoy the experience. I had a carboy cap increase in size due to an overnight Star San soak. Never again...

Cheers!
 

odie

Well-Known Member
Joined
Dec 18, 2016
Messages
1,917
Reaction score
1,031
Location
CC, TX
I've found that Stansan stays clear when mixed with distilled water. I assume it could be kept a while and used without issues.

When I used tap water it turned cloudy after a short while.
 

renstyle

Supporting Member
HBT Supporter
Joined
Aug 20, 2020
Messages
392
Reaction score
439
Location
Central Iowa
Same here. Use waste RO water into a 23L keg to make a batch of starSan as I top off carboys for the next brew day.

It stays clear in the keg this way for weeks for sure. I use prolly half during the current brew day and the rest to top off containers, misc cleaning, etc.

One oz of starSan (more or less) is used each brew day, the 32oz bottle has lasted over a year.
 
Last edited:

odie

Well-Known Member
Joined
Dec 18, 2016
Messages
1,917
Reaction score
1,031
Location
CC, TX
I keep starsan mix in small spray bottles for rinsing taps after a drinking session. Stays clear for weeks with distilled water.
 

Wolfbayte

Third Most Interesting Man in his Cul-de-Sac
Joined
Mar 31, 2012
Messages
225
Reaction score
143
Location
Phoenix
I picked up a 5g food grade bucket w/lid at Home Depot and filled it with RO water from the coin-op machine at the grocery store. Added a cap full of StarSan when I got home and used it for brewing. Used it again on bottling day. Again and again, since Jan 2019. Fill my bottle washer and my spray bottle from it. It's about 1/2 full now, but still clear as day and foams up nice. I keep saying, "after this batch, I'm going to toss it and start over." Brewed 5 batches so far this year. Yet I've yet to do it. Next batch maybe. Or the one after that. I promise.
 

DarrellQ

Supporting Member
HBT Supporter
Joined
Jul 25, 2020
Messages
194
Reaction score
77
Location
Northern Virginia
I'm all for you doing what works for you. Not saving it works for me.

The question of how long StarSan is effective after being mixed with water comes up often. And the fact that how long it lasts depends on things unique to each situation. So for me, I see no reason to not use fresh mix every time and avoid the potential pitfalls.

Still how much more effort is it to fill a container and add the measured amount of sanitizer to it? My laundry sink faucet fills a five gallon bucket in 40 seconds. Another gallon a few more seconds.

As for hop sacks, they only need a few minutes in sanitizer. Assuming of course they are clean when they are put in.
Not a lot of effort but that stuff ain't cheap!
 

IslandLizard

Progressive Brewing
Staff member
Mod
HBT Supporter
Joined
Jan 9, 2013
Messages
19,141
Reaction score
9,380
Location
Pasadena, MD
When my starsan goes cloudy too soon after mixing, I just add a bit of 85% phosphoric acid to drop the pH through the floor again.
We have soft(ish) tap water, very suitable for most brewing water, as is, with a proper Campden treatment to remove Chlorine. Although it has very little mineral content, my StarSan starts to get cloudy after a day or so, too. The pH remains well under 3.0 (around 2.7) so there's not always need to add acid simply because it gets cloudy.

IIRC, a fresh Starsan working solution in RO or distilled water has a pH of 2.50 or thereabout. I need to remeasure that or find my notes.

85% Phosphoric acid is crazy strong for routine use. I'd make a 10% strength dilution with some and use that. Much easier to measure 3.5 ml than .3 ml, and with a far smaller measuring error.

@Silver_Is_Money posted a thread with calculations to prepare Phosphoric Acid dilutions:
I've used his thread and calculations to make proper Phosphoric Acid dilutions that are much easier to work with than the 85% stock.

These measurements are from my own notes:
  1. Measure out 18.34 ml of 85% Phosphoric Acid.
  2. Or 30.97 gram. It's usually easier and more precise for homebrewers to weigh small amounts on a $15 precision scale, like the one used for brewing salts, than measuring small volumes accurately.
  3. Add the acid slowly (and quantitatively*) to ~100 ml distilled water (at 20°C/68F), while stirring. Stir well to homogenize.
  4. Top up to 250 ml with more distilled water, while slowly mixing/stirring.
  5. Using a volumetric flask will get you better accuracy than a wide beaker. Or weigh it.**
* Quantitatively means making sure all the acid measured or weighed makes it into your final solution. E.g. after adding the acid to the distilled water, rinse the measuring vial or container with a relatively small amount of more distilled water and add that to your volumetric flask or mixing vessel. Do that 3-5 times.

** In lieu of a volumetric flask, you could weigh out the final volume on a (decent) scale. 250 ml of 10% Phosphoric Acid weighs 263.25 gram.

Using a scale with a precision of around 1-2 gram is fine. One you may already use for weighing hops, or in the kitchen for baking. Although there may be a total weighing error of 1-2 gram, it's only 0.4-0.8% of the total in this case, and very acceptable given the total volume weighed (263 gram).

IOW, due to the scale's inherent (in)accuracy and/or internal rounding you may end up with actually 265 gram instead of the intended 263 gram (which is what the scale displays). That would mean you'd have [revised] 9.92% Phosphoric Acid on hand instead of 10.00%.
 
Last edited:

Wolfbayte

Third Most Interesting Man in his Cul-de-Sac
Joined
Mar 31, 2012
Messages
225
Reaction score
143
Location
Phoenix
Must be a large cap, you'd need 1 fl oz (~30 ml) per 5 gallons. Or 6 ml per gallon.
Better check you're using the right amount...
Yes, 1 fl. oz. By "cap" I meant the part of the bottle that measures the dosage as you squeeze. I must have had Nyquil on my mind.
 
Top