Peracetic acid

[dogchillibilly]

Having given up trying to get hold of starsan in the uk and following a trip to a local micro, i decided to start using peracetic acid as a sanitiser.
Seeing them using it made me realise that it was so much easier than my existing milton then rinse and rinse and rinse process.
So i ordered some off of ebay.
I made up 20l at 1:100 ratio and used it for bottling (it didnt have a % on the box so i assumed 5%).

Question: I have the 20l of mixed solution sitting in an old fermenting bin with the lid on. How long can i keep it? At the micro i believe it was certainly a few days old.

Thanks

[steve_flack]

I tend not to keep mine diluted so I can't answer your question.

Can you post a link to the ebay seller?

[DarloDave]

I've stored some diluted peracetic in an FV for a couple of weeks, still smelled really strong, I used it with no problems

[Aleman]

The effective lifetime of a diluted solution of peracetic acid is around an hour! It will smell really strong but the acetic acid is not the killer the hydrogen peroxide is and this breaks down very easily.

Used for storing hoses and tubing the killing side of it is done at the beginning . . . but I wouldn't trust the hoses after a couple of weeks of storage . . . following day will be fine though.

[dogchillibilly]

I tend not to keep mine diluted so I can't answer your question.

Can you post a link to the ebay seller?

http://cgi.ebay.co.uk/Peracetic-Acid-Pe ... 20ae9c0d29

[WishboneBrewery]

We keep our Peracetic Acid in diluted state for 5 days then chuck it if its not been used.

[dogchillibilly]

thanks for your input guys.
I'll play safe and chuck after 2.
i mixed up a smaller batch this time - 10l.

that was more than enough and should mean i get quite a bit of mileage of my 5l

[Scotty]

yeah, keep it in its diluted state for upto a week then throw it away. The benefit of peracetic acid is that you can use ordinary tap water and not have to worry about ph levels. Plus at a 1:100 ratio, your 5l will last forever!

[Aleman]

No It won't!

Even in its concentrated form Peracetic acid continually evolves oxygen (from the breakdown of the hydrogen peroxide), and as its the peroxide that is the biocide once those levels fall then it will cease to be as effective. . . . Keep peracetic in the fridge to slow down the rate of breakdown though. . . . Murphys reckon on about 3-6 months for a lifetime of the concentrate. . . . (although they are the retailers )

The rate of breakdown is much more rapid when diluted. . . . again its probably like the discussion on the effectiveness of iodophors . . . As long as the equipment is clean when it goes into the disinfecting solution . . . then you are likely to get away with a less than ideal concentration of disinfectant . . . plus if the contact times are extended, again a lower concentration will work.

And for a 5% solution of peracetic . . . the recommended soaking solution is 1:66 . . . .For CIP work it varies between 1:100 and 1:200 . . . and if you have a fogger then you can get away with 1:266 . . .as long as you have breathing gear and and NCB suit to apply it

[Aleman]

All this fuss about shelf life of dilluted and undilluted peracetic acid and the fact you wouldn't want it to come into contact with your skin makes me glad i've stuck with plain old cheap, cheerful, long lasting, reusable, and safe star san

I can see myself going that way as well . . . Once I've used up my Iodophor

[Aleman]

Yes the analysis for Smartprice and Blackpool water is very similar

[Scotty]

No It won't!

Even in its concentrated form Peracetic acid continually evolves oxygen (from the breakdown of the hydrogen peroxide), and as its the peroxide that is the biocide once those levels fall then it will cease to be as effective. . . . Keep peracetic in the fridge to slow down the rate of breakdown though. . . . Murphys reckon on about 3-6 months for a lifetime of the concentrate. . . . (although they are the retailers )

The rate of breakdown is much more rapid when diluted. . . . again its probably like the discussion on the effectiveness of iodophors . . . As long as the equipment is clean when it goes into the disinfecting solution . . . then you are likely to get away with a less than ideal concentration of disinfectant . . . plus if the contact times are extended, again a lower concentration will work.

And for a 5% solution of peracetic . . . the recommended soaking solution is 1:66 . . . .For CIP work it varies between 1:100 and 1:200 . . . and if you have a fogger then you can get away with 1:266 . . .as long as you have breathing gear and and NCB suit to apply it

Easy tiger!

Cheers for the heads-up. Saying that, I've had diluted PA previously in a trigger bottle that has been over a month old which I've used to sterilise an FV's and taps and had no problems. Maybe I'm lucky?!

Even so, peracetic would be a good alternative to star san

[boingy]

That's the problem with sanitisation. It's very hard to know how effective it is.

[Aleman]

Agreed Chris, I think it was Graham who said that because we clean our kit very effectively we don't have a requirement for a total biocide as a disinfectant. This explains why people who just rinse with a dilute sulphite solution have very few, if any, infections, why a dilute videne/betadine solution works, and old peracetic is effective. While in some industries using harsh chemicals at the maximum concentration is a requirement I think that in the majority of home brewing cases we can 'get away' with using the lowest concentrations possible . . . as long as we have an effective cleaning regime in the first place

After all take a handful of dirt and pressure cook it for 30 minutes . . .put it in the oven at 180C for an hour to dry it . . . . It will be as sterile as hell . . . but would still make your beer taste of dirt if you put it in a fermenter

[boingy]

I was really surprised to read in The Microbrewers Handbook a suggestion that you probably don't need to clean or sanitise the bottles as long as they are still wrapped and "fresh" from the supplier. Not sure I would risk that...