Wild Yeast Contamination

[BrewMU]

Major screw up: I waited too long (4 days) to pitch my Altbier, and wild yeast took hold. It had been throwing up a fine-bubbled white krausen for a few hours before I got to it, airlock bubbling. I managed to siphon maybe half of it off, then went ahead and pitched a healthy starter of actual beer yeast (~.6 of a L of wort into which I'd dumped a Wyeast 1007 German Ale smack-pack).

Does the ale yeast stand a chance of winning the yeast battle, or is my beer already ruined?

There is a little consolation: I have a promising batch of CC in the fermenter, a tasty stout just about ready to drink, and enough grain left for at least one more batch of something.

 

[stevehollx]

I doubt that racking some of the krausen off would do anything, and you're already going to have some of the flavors from that unknown yeast/critter.

You should tuck this fermenter in a dark corner and just let this beer do its thing for ~9 months and see what you get. May end up pleasantly funky or sour. ;-)

 

[tallgirl]

If you had enough of a colony for the airlock to be bubbling away, you've already lost the battle. The wild yeast likely outnumbers whatever you pitched by several orders of magnitude.

I'm with the suggestion to just let it ferment out and see what turns up. Some wild yeasts are okay, some are just plain nasty.

 

[theredben]

Why do you suspect wild yeast? Have you tasted it? All of our fermenters are covered in viable yeast leftovers from previous brews. It would result in a serious underpitch, but may still be drinkable. Let us know.

 

[BrewMU]

It was clear from the look of the Krausen and the smell that it wasn't beer yeast.

 

[day_trippr]

[...]All of our fermenters are covered in viable yeast leftovers from previous brews. [...]

"Your" fermenters may be in a constant state of contamination, but "our" fermenters are rigorously cleaned and sanitized before every use...

Cheers!

 

[theredben]

"Your" fermenters may be in a constant state of contamination, but "our" fermenters are rigorously cleaned and sanitized before every use...

Cheers!

Yes, rigorously cleaned, sanitized, and still covered in viabile yeast leftovers. Seriously, Star-san is designed not to kill yeast!

 

[day_trippr]

[...]Seriously, Star-san is designed not to kill yeast!

What ever might have led you to that conclusion?

Cheers!

 

[jfr1111]

Why do you suspect wild yeast? Have you tasted it? All of our fermenters are covered in viable yeast leftovers from previous brews. It would result in a serious underpitch, but may still be drinkable. Let us know.

Wait what ?

 

[day_trippr]

http://www.fivestarchemicals.com/wp-content/uploads/StarSanTech-HB2.pdf

fwiw, the word "fungicide" should provide a clue...unless I have to correlate yeast with fungus...which would be sad...

Cheers!

 

[BrewMU]

Thanks for the help. I actually was just reading about Star-San: it will kill isolated yeast, on or in a carboy for example, but it depends on a ph of 3.5 or below. The acid is swamped out in the wort; when you pour it in, ph goes up to ~5.5, Star-San quits working, won't kill yeast.

 

[theredben]

http://www.google.com/m/url?client=...8QFjAA&usg=AFQjCNEW_8AZxiwWImuJOVLFD1Ju7l0KiA
^^^ A very good handout, scroll down about half way to find the "Acid Anionic Sanitizers"
Seriously, Star-san is not very good at killing yeasts since it is an acid anionic sanitizer. What it is very good at is being shelf stable (homebrewers do not use very much) and killing bacteria. Since bacteria are our main concern, Star-san is really a wonder product!

 

[stevehollx]

http://www.google.com/m/url?client=...8QFjAA&usg=AFQjCNEW_8AZxiwWImuJOVLFD1Ju7l0KiA
^^^ A very good handout, scroll down about half way to find the "Acid Anionic Sanitizers"
Seriously, Star-san is not very good at killing yeasts since it is an acid anionic sanitizer. What it is very good at is being shelf stable (homebrewers do not use very much) and killing bacteria. Since bacteria are our main concern, Star-san is really a wonder product!

Well I'm curious then, what is an effective sanitizer for killing yeast (specifically Brett, since any other yeast would be welcome)? I think I've heard Idophor is the stronger sanitizer?

I assume I've got a lot of Brett floating around my place from brewing so much sour beer, so a strategy to wack the Brett before pitching wouldn't be a bad thing to have...

 

[theredben]

Bleach is a good general biocide (bacteria/yeast/algae etc...), it is cheap, readily available, and under my sink. Bleach then rinse with Star-san is what I would use if I had a Brett problem. Just remember that Bleach solutions lose strength over time, and should not be stored for very long, and cannot be reused like Star-san

 

[BrewMU]

I don't know if anybody is checking this thread, but there may be good news - the krausen took off after I pitched the Ger. Ale starter, and it looks normal. The wild stuff was white and fine bubbled, this is big brown chunks - looks like beer yeast. Fingers crossed.
Btw, Star-San DOES kill yeast - if the ph is <3.5. It's acidity is swamped by the wort, so it won't kill your pitched yeast.
If I'd have thought of it I would have poured some boiling water into the carboy before pitching, or just re-boiled the wort. That occured to me ~ one minute too late.