Sanitizer question

[raymarkson]

I seem to have a wild yeast that has taken up residence in my brew space that IODOPHOR works on, but star San does not.

About a year ago, I had an issue with something giving my beers a really harsh astringency and a slight phenolic flavor that muted all of the hop flavor and aroma. I do understand that astringency is usually attributed to tannins extracted during the mash/sparge because of high temperature and high ph. However, I monitor my ph during the mash and sparge and it is always between 5.2-5.4 and my sparge does not get above 168f.
I am also sure that it was not chlorophenols because I either use RO water or tap water that has been treated with campden Tablets.

I finally determined that it must have been a wild yeast that was causing the unwanted flavor. However, my cleaning and sanitizing routine is really solid. I clean with oxy clean and sanitize EVERYTHING that my beer touches on the cold side with Star San. However, the flavor kept recurring.Then, out if desperation, I tried using IODOPHOR instead of Star San. That seemed to work! So I continued to use IODOPHOR for several more months with no problems.

After a while, I stated thinking that maybe it was just a coincidence that the IODOPHOR worked to stop the suspected wild yeast from infecting my beer, so I switched back to Star San. Star San did seem fine for a couple of more brews but now the wild yeast has reared its ugly head again. I have two brews with the same harsh astringency and slight phenolics that covers up ALL hop flavor and aroma. It's very much like those beers from a year ago.

Is it plausible that IODOPHOR could be more effective on some microorganisms than Star San? Also, could the reverse be true? I am going to switch back to IODOPHOR for now to see if it works again.

I'm also wondering if anyone else has experienced this.

 

[Vale71]

IODOPHOR is a true disinfectant and is very effective against a wide range of bacteria and viruses. StarSan is just a bacteriostatc agent and much less effective. So yes, what you say is plausible. If you brew in a heavily contaminated environment then StarSan might very well not be enough for you.

 

[raymarkson]

IODOPHOR is a true disinfectant and is very effective against a wide range of bacteria and viruses. StarSan is just a bacteriostatc agent and much less effective. So yes, what you say is plausible. If you brew in a heavily contaminated environment then StarSan might very well not be enough for you.

That's interesting... I was not aware of this difference. Thanks for the knowlege!

 

[Novacor]

Once a year I sanitize all my brew equipment with iodophor. My mindset is to kill anything that might be building up a resistance to the StarSan that I use every other time.

 

[Qhrumphf]

There's been papers in the food safety industry that the active ingredient in Star-San is effective against bacteria but less so against yeasts. Iodophor is more broad spectrum. Note that this was not brewing specific, and not specific to Star-San but rather the specific component, dodecylbenzenesulfonic acid.

There was some research posted up on Milk the Funk showing it was indeed effective, that was specific to Star-San and brewing.

So I'd say jury is out. Or at least disputed.

I prefer Iodophor since it's easier to titrate to confirm effectiveness, and doesn't foam. If it's more effective to boot, then great.

Star San does have two good uses that Iodophor lacks- leak testing a pressure vessel like a unitank or draft system, and as a secondary rinse (after a water rinse) after using a sodium hydroxide cleaner (ie caustic) since the phosphoric acid in it will neutralize any remaining caustic that might have escaped a water rinse.

 

[Qhrumphf]

(a caustic beer line cleaner being a good example- rinse lines with water then rinse with Star-San)

 

[JimRausch]

Starsan is less effective than iodofor against yeast.
I had a similar issue a few years back and believe it was a diastatic yeast in my racking siphon or bottling wand. In addition to the phenolic off-flavor, it led to some bottles being overcarbed. Pretty sure it came from a batch I did with Belle Saison yeast. Switching to iodofor helped. So did switching out the equipment.