Once you get vinegar is it permanently contaminated?

[Calder]

I revived an old yeast last week. Made a low abv starter and it fired up quickly. Stepped up to half liter and all went well. Stepped up to 1.5 liters and it went fine.

In decanting the liquid smelled vinegar. I tasted it, and sure enough, it tasted faintly of vinegar.

I decanted the liquid, added another 1.5 liters of wort, but this time only shook at the start and let it ferment under airlock.

This evening, I opened it, and it sure smells of vinegar. I thought that if I kept it under airlock, acetobacter couldn't do its work.

Is all lost for this yeast?

The yeast is WLP Brett-B. Could I be smelling sonething else?

 

[dmtaylor]

Personally I think Brett and cider don't get along very well. Could be a Brett thing. But vinegar is pretty unmistakable. And yes, if you have vinegar, well then it's not going to change back, it's contaminated. Not to worry, though -- if you are resourceful, you can find ways to use vinegar for cooking and around the house.

 

[Calder]

Personally I think Brett and cider don't get along very well. Could be a Brett thing. But vinegar is pretty unmistakable. And yes, if you have vinegar, well then it's not going to change back, it's contaminated. Not to worry, though -- if you are resourceful, you can find ways to use vinegar for cooking and around the house.

Where did the cider comment come from. This is starter wort. ......... But I think Brett fermented cider comes out pretty good. The yeast adds lots of flavor.

Back to my original query; I'm not concerned about the starter wort/beer. What I'm wanting to know, is if I can save the yeast, or if I have to toss it. Could I wash it?

 

[day_trippr]

The yeast - and the starter wort, the vessel, and anything that touched them - is infected, and unless you want that flavor in your finished beer, cannot be saved...

 

[dmtaylor]

Oops. Sorry, man, I've had cider on the brain all week. Regardless, acetobacter is typically what causes acetification, or turning to vinegar. Happens with malt beverages as well as cider and wine. If contaminated, you'd have to mess around with agar plates etc. to separate out the good stuff, which I would guess is more pain than it's worth, but could be done.

 

[BrewSavage]

If it isn't drinkable make a sauerbraten. I'm getting hungry just thinking about it.

 

[j1n]

The yeast - and the starter wort, the vessel, and anything that touched them - is infected, and unless you want that flavor in your finished beer, cannot be saved...

This^

unless you want a ton of malt vinegar...

 

[jfr1111]

I'm far from being an expert on the subject of wild fermentation, but I do read a lot on a topic once I start to get interested in it.

While Brett will not typically produce sour beer, it seems that some strains can produce acetic acid when they have access to oxygen. Brett starter wort that has been aerated could maybe produce acetic acid in enough concentration to give the aroma that you describe.

I would ask for help in the wild/lambic brewing forum.

There's always the possibility that your culture is mixed with acetobacter though, as was previously pointed out.

 

[Calder]

I'm far from being an expert on the subject of wild fermentation, but I do read a lot on a topic once I start to get interested in it.

While Brett will not typically produce sour beer, it seems that some strains can produce acetic acid when they have access to oxygen. Brett starter wort that has been aerated could maybe produce acetic acid in enough concentration to give the aroma that you describe.

I would ask for help in the wild/lambic brewing forum.

There's always the possibility that your culture is mixed with acetobacter though, as was previously pointed out.

The last starter was deliberatly not excessively shaken to rule out the possibility of the Brett making it (which I don't think it does as a primary yeast anyway).

I'll taste the starter wort this evening, and if there is any acetic acid in there, I'll dump the yeast. It had a good run; I probably used it in over 20 batches over 5 years, with saving bits of starters and pitching slurry.

 

[jfr1111]

The last starter was deliberatly not excessively shaken to rule out the possibility of the Brett making it (which I don't think it does as a primary yeast anyway).

I'll taste the starter wort this evening, and if there is any acetic acid in there, I'll dump the yeast. It had a good run; I probably used it in over 20 batches over 5 years, with saving bits of starters and pitching slurry.

This seems like the safe option.

 

[defrandj1]

Add two tablets of chlorine dioxide (you can buy it at dicks sporting goods). It will kill all the bugs and not harm the yeast.

 

[Agate]

I'm far from being an expert on the subject of wild fermentation, but I do read a lot on a topic once I start to get interested in it.



While Brett will not typically produce sour beer, it seems that some strains can produce acetic acid when they have access to oxygen. Brett starter wort that has been aerated could maybe produce acetic acid in enough concentration to give the aroma that you describe.



I would ask for help in the wild/lambic brewing forum.



There's always the possibility that your culture is mixed with acetobacter though, as was previously pointed out.

^^^ Nailed it. I'd step it up again, no shaking and under an airlock, and see if it comes back. Brett can be sharply acetic with oxygen, even as a primary yeast once it's past the growth phase.

 

[feinbera]

Well, OK, silly question – you said you've done ~20 previous starters with this yeast, did any of them smell even faintly acetic? If not, either you've got acetobacter or the yeast has otherwise mutated, neither of which bodes well for it performing as it has in the other 20 batches.

This chlorine dioxide looks intriguing, but at a certain point, you gotta decide if it's just easier to go see your friends at White Labs for a fresh culture.

 

[defrandj1]

The chlorine dioxide will kill any bacteria (lacto, pedio, and aceto) in the yeast, however, if your issue is mutation, there is really no fix for that besides starting from a pure culture.

 

[Agate]

Well, OK, silly question – you said you've done ~20 previous starters with this yeast, did any of them smell even faintly acetic? If not, either you've got acetobacter or the yeast has otherwise mutated, neither of which bodes well for it performing as it has in the other 20 batches.

This chlorine dioxide looks intriguing, but at a certain point, you gotta decide if it's just easier to go see your friends at White Labs for a fresh culture.

Sure, take the simplest, most obvious solution. Why didn't I think of that... [emoji13]