How Long Will StarSan Last For?

[LetsBrewBeer]

Ever wondered just how long StarSan retains its effectiveness? check out my short article that discusses how to get the most from your StarSan sanitizer.

 

[McMullan]

It's a common belief among home brewers that Starsan working solutions remain sufficiently active for months. It's claimed as long as the pH remains at about 2, it's good to use. Unfortunately, it's not just about pH. The detergent/surfactant in Starsan makes cell membranes more permeable thus allowing the low pH solution to enter and have a sanitising effect (on mainly bacteria cells not yeast*). At working concentrations under acidic conditions, especially at room temperature, the detergent isn't necessarily stable over time. Without sufficient detergent the sanitising solution becomes less effective, even if pH=2. This is why the manufacturer recommends - for best results - preparing fresh sanitiser and using it within a day or two.

My advice for home brewers is prepare 1L Starsan solution on brew day. That's more than enough to sanitise multiple standard (5Gal) FVs, kegs or bottles, peripherals and then store cool in a spray bottle until the batch is packaged. In my experience, 2-3L is enough recirculated in a large conical FV, although low-foaming alternatives to Starsan are preferable when recirculating.

Keeping buckets of Starsan solution for months doesn't save much money or time and can reduce the probability of making a great beer.

When disposing of spent Starsan down the sink use plenty of water to dilute for environmental reasons. Ideally, as with all household chemical solutions, it should be disposed of appropriately at a local public service already paid for by taxes.

*Use bleach or iodophor solutions to kill unwanted yeast cells. It's good practice to do this occasionally regardless of perceptions.

 

[Kevin58]

I mix up just a small amount on brewday and use that on everything. Since Starsan only needs to contact the surface... in other words, you don't have to soak things... all you need is a spray bottle to wet surfaces of the things you want to sanitize. What is left over at the end of the day is put in a jar for my fermenter blow-off and disposed of when fermentation is complete.

FWIW: per the manufacturers website...

How long is Star San good for once it’s mixed into a solution?​

Star San is an EPAs registered sanitizer and must be used immediately. We do not recommend using it if has been in solution longer than an hour.

 

[BOB357]

It's a common belief among home brewers that Starsan working solutions remain sufficiently active for months. It's claimed as long as the pH remains at about 2, it's good to use. Unfortunately, it's not just about pH. The detergent/surfactant in Starsan makes cell membranes more permeable thus allowing the low pH solution to enter and have a sanitising effect (on mainly bacteria cells not yeast*). At working concentrations under acidic conditions, especially at room temperature, the detergent isn't necessarily stable over time. Without sufficient detergent the sanitising solution becomes less effective, even if pH=2. This is why the manufacturer recommends - for best results - preparing fresh sanitiser and using it within a day or two.

My advice for home brewers is prepare 1L Starsan solution on brew day. That's more than enough to sanitise multiple standard (5Gal) FVs, kegs or bottles, peripherals and then store cool in a spray bottle until the batch is packaged. In my experience, 2-3L is enough recirculated in a large conical FV, although low-foaming alternatives to Starsan are preferable when recirculating.

Keeping buckets of Starsan solution for months doesn't save much money or time and can reduce the probability of making a great beer.

When disposing of spent Starsan down the sink use plenty of water to dilute for environmental reasons. Ideally, as with all household chemical solutions, it should be disposed of appropriately at a local public service already paid for by taxes.

*Use bleach or iodophor solutions to kill unwanted yeast cells. It's good practice to do this occasionally regardless of perceptions.

"It's claimed as long as the pH remains at about 2, it's good to use."

You might want to check your numbers.

 

[McMullan]

You might want to check your numbers.

Not really, because it's not a concept I subscribe to. Obviously. Nor have I ever bothered measuring pH of fresh working Starsan solution prepped with my tap water. I've only assessed its effects on microbial cultures using microscopy and spectrometry measurements. Why I choose to use it fresh and recommend alternatives for killing unwanted yeast, I guess. But feel free to express antagonism. It makes me chuckle

 

[BOB357]

Not being antagonistic. Some folks look to these forums for information so accuracy matters.

For those folks, the effective pH range for StarSan is 3.5 or lower.