How long will something stay "Sanitized for use"?

I use Star-san in a spray bottle, and I'm afraid I'm over-dispensing. So, how long can my freshly sanitized instruments+equipment sit before I have to re-sanitize?

I think technically as long as the pH is below 3. But that's in wet form, like in a carboy. Dried up on the surface, it's hard to say. Probably as long as it takes dust to settle, and begin harboring bacteria.

To be safe, I'd just sanitize everything before you need it.

I usually clean everything really well and then sanitize right before use.

I pre-sanitize my bottles in Star San, making sure the contact time is sufficient. I dump and put foil over the necks and use them whenever I am ready. I personally would not hesitate doing this with my carboy either. I would assign a 3 month expiration for dust bunnies, however.

I would be worried about leaving things sanitized for a long time. It is extremely easy to sanitize things so I would just right before use. I know bacteria isnt magic and it doesn't just appear in places, and a foil cover theoretically should protect it, but who knows. 5 gallons of beer is worth more than three minutes of my time to sanitize something.

lextasy23 said:

I think technically as long as the pH is below 3. But that's in wet form, like in a carboy. Dried up on the surface, it's hard to say. Probably as long as it takes dust to settle, and begin harboring bacteria.

To be safe, I'd just sanitize everything before you need it.

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ph lower than 3.5

I listened to a Basic Brewing Radio podcast with someone from 5star chemicals, Charlie something I think. Anyways, he as asked this same question, and he said to sanitize immediately before use. Clean well before storage, but don't bother sanitizing until right before use.

when i store my carboys i put half a cup of starsan in them, cap em, shake it up, and store them. a sealed container would remain sanitised inside indefinately. if you are talking about something that isnt sealed, i would sanitize it again right before use.

audger said:

when i store my carboys i put half a cup of starsan in them, cap em, shake it up, and store them. a sealed container would remain sanitised inside indefinately. if you are talking about something that isnt sealed, i would sanitize it again right before use.

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Depending on how long you're storing the carboy, this isn't necessarily the best idea.

Starsan doesn't kill 100% of bacteria or other creepy-crawlies. It kills like 99.9% of them, and makes for a very hostile environment for new ones to pop into.

But, bacteria being bacteria, that .1% that survive will multiply. Sure, maybe 99.9% of the offspring don't survive - but bacteria multiply fast. Before long, even if 99.9% of each generation is dying off, you're still running the risk of a bacteria colony growing large enough to introduce risk to whatver you ferment in there.

Best bet is always to sanitize just before use - kill off as much of the bad stuff as you can so only the good stuff (your yeast) get a chance to really take off.

im not sure that i see how killing 99.9% now or 99.9% later are any different...

the starsan (as long as you mix it with RO or distilled water) will not loose its disinfectant power just sitting there in a clean sealed glass container, so anything that grows in the carboy after one application of starsan still wouldnt be killed after another application of the same exact stuff.

if you are suggesting that a properly mixed starsan soloution will support the growth of bacteria, i am going to challenge you to back that up with evidence.

If whatever the starsan was in was completely filled with solution then your skepticism makes sense. But if parts of the conical, bottle or whatever was dry then something could certainly grow inside. I always put some starsan in right after cleaning, then before use I will dump that and respray just before use.

im still skeptical about what you said.

imagine you have a completely sealed container. you take a cup of starsan, put it inside, shake it up and coat the entire inside surface with starsan. then you let it sit there and the starsan pool at the bottom. i dont know where the bacteria would be able to get in from. i suppose you could argue that it is suspended in the air inside, but as soon as it touched the inside surface it would be killed because of the starsan residue. even if, by chance, the residue wasnt enough to kill that single bacterium, it would be killed the next time you shook the container and re-wet the surface.

assuming that the starsan didnt go bad while it was in there, i dont get the difference between putting the starsan in the carboy now, versus putting it in later right before you put beer in it. its the same exact sanitizer, regardless of time.

i would even argue that it is better to put it in sooner, as bacteria grow in numbers exponentially. if you do not sanitize the carboy before you store it, you are storing it with a drasticly higher bacterial concentration to start with, which, would have an even better chance to grow.

so for example, if you stored it unsanitized for 10 days, starting with a bacterial count of (pulling number out of thin air for example) 5 million. say they gain 5% per day. that is 81 million bacteria after 10 days. if starsan kills 99.9%, you are left with 814,000 bacteria after you sanitize it before use.

if you start with 5 million bacteria (unsanitized) at day 1 and put sanitizer in there from the begining, you end up starting with 500,000 bacteria. say they grow the same 5% per day, that is 814,000 after 10 days. you then sanitize it to kill 99.9%, leaving only 81,000 bacteria. that is 10 times less bacterial load.

that is all assuming: bacteria can grow at the same rate in a soloution of starsan as they would naturally, which i would question, and that the starsan lost its effectiveness after only a short amount of time, which we know it doesnt. im sure its mostly moot, though, and i am making it way more complicated then necessary. people have been making beer with great results even before starsan was invented ( i know, right!).

thats how it works in my head anyway... its a crazy place in here.

A best practice: sanitize immediately before use to avoid any contamination, sure.

But, I will continue to pre-sanitize my bottles. Scientifically, I agree with audger. To further support this case, bacteria/fungi need nutrients and moisture to *proliferate*; they can remain dormant without these things. By cleaning we remove the nutrients (and bioburden) necessary for proliferation, by sanitizing we reduce the bioburden from the item, and by letting the item dry we reduce the moisture.

If we can demonstrate that your method of preparing StarSan remains stable and effective in your conditions, you could go even further by leaving the StarSan in the carboy.

Although not the same method of sanitization, I have seen autoclave sterilized growth media in erlenmeyers remain sterile with foil covers for over a year. Granted, sterile and sanitized are very different terms. My point is that unless you heat a container like this up and cool it down repeatedly, it is not going to suck contaminants inside of it.

I used to leave sanitizer in both my carboys and bottling bucket between uses. Until today. I just went to transfer some wine to a secondary and was going to mix up some sanitizer in the bottling bucket. There was mold growing on the inside. Went to get my carboy. There was a colony of mold floating on top of the sanitizer.
Needless to say everything is getting the living crap bleached out of it, rinsed and sanitized. From now on I store things dry and sanitize before use.
Everyone's situation is different, but trying to keep my equipment "pre-sanitized" didn't work too well for me.

ruralbrew said:

I used to leave sanitizer in both my carboys and bottling bucket between uses. Until today. I just went to transfer some wine to a secondary and was going to mix up some sanitizer in the bottling bucket. There was mold growing on the inside. Went to get my carboy. There was a colony of mold floating on top of the sanitizer.
Needless to say everything is getting the living crap bleached out of it, rinsed and sanitized. From now on I store things dry and sanitize before use.
Everyone's situation is different, but trying to keep my equipment "pre-sanitized" didn't work too well for me.

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Interesting....StarSan? Distilled Water? Covered?

Once the ph neutralizes StarSan is a nutrient... tasty food for any random bacterium.