Acetic acid from Roeselare blend

I did my first Flanders Red 3 months ago, split batch, half with various dregs and half without. Last night I racked the one with dregs to a secondary and while it didn't taste like straight up vinegar, it did have a slight acetic acid taste to it. I'm not sure if I have an acetobacter infection or if it's common with Roeselare (I didn't taste the non-dregs half)? Will this mellow at all? I know a slight acetic taste is true to the Flanders style and all.

There might have been a lot of oxygen available for the bacteria to create it. If you must secondary, and you don't have to, consider transferring to a vessel purged with co2. Or just leave it on the cake in primary.

I don't think that will mellow with time, but maybe someone has better info for you.

acetic typically will not age out.

perhaps some of the dregs you added had aceto?

if the aceto becomes too much, you could blend your two batches. that would dilute down the acetic.

be careful to minimize exposure to oxygen from now on, use a stopper/bung that provide a solid seal, don't sample more than absolutely necessary (i.e., not at all until it's 12 months), etc.

sweetcell said:

acetic typically will not age out.

perhaps some of the dregs you added had aceto?

if the aceto becomes too much, you could blend your two batches. that would dilute down the acetic.

be careful to minimize exposure to oxygen from now on, use a stopper/bug that provide a solid seal, don't sample more than absolutely necessary (i.e., not at all until it's 12 months), etc.

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I was antsy and sampled after only a month, now I know better. My previous sour I didn't have any issues with acetobacter while taking samples every few months, but I know you can't really predict these things.

Brett3rThanU said:

My previous sour I didn't have any issues with acetobacter while taking samples every few months, but I know you can't really predict these things.

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if your sanitation is good, typically taking a few samples shouldn't be a prob. for whatever reason you got aceto in there (from the dregs, some floated in, or whatever) so now you need to be extra careful about letting in more O2.

That blend includes Brett strains. Brett does produce acetic acid when there is oxygen present.

true, but it takes a lot of O2 to get brett to create acetic. he was racking out of primary, so my initial impression is that it hasn't been long enough, with enough O2, to get aceto going. now if the OP tells us that the beer sat in primary for a long time, was opened several times, etc. then maybe enough O2 got in there.

It's been in primary for 3 months, only opened it once.

3 months could do it, if enough air got in there. any chance you were using one of those rubber carboy caps?

otherwise, i wouldn't think that a single opening with a good seal would do it, but i'm certainly no expert.

http://m.imgur.com/gFrX9m2
One of those. I was under the impression it's okay to leave in the primary for extended periods of time.

Brett3rThanU said:

http://m.imgur.com/gFrX9m2
One of those. I was under the impression it's okay to leave in the primary for extended periods of time.

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yeah, that type of bung provides a solid seal provided that it's jammed in with a little force. so that's not likely the problem...

question: how certain are you that it is acetic acid that you tasted?

regardless, at this point the best thing to do is leave it sealed up until it's time to package. time will tell!

Honestly, not 100% sure. It's just a little more sharp than most of the sours I have tasted. Could just be very tart. Regardless, I'm just going to let it sit another year and assess then. I could just be worrying. Starting to do sour beer makes me feel like I'm just starting to homebrew all over again.

I'm still beginning but I've made a point of getting some easy sugars into my sours the infrequent times I open the container for a gravity sample and taste. Not enough to bump the gravity up much (or set back the wait) but enough to get the yeasts to scrub the O2 from the headspace (dme, honey, fruit and priming sugar, juice concentrate -- any option boiled in water like a starter). If you don't have a keg system but have a CO2 inflator for bikes, I'm told they are great a way to purge your headspace as well.

sweetcell said:

true, but it takes a lot of O2 to get brett to create acetic.

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Nope, doesn't take much at all. Micro-oxygenation is helpful for inducing brett to throw a little acetic acid into the mix. If the OP was fermenting in a plastic bucket, the opportunity for micro-oxygenation is there.

mabrungard said:

Nope, doesn't take much at all. Micro-oxygenation is helpful for inducing brett to throw a little acetic acid into the mix. If the OP was fermenting in a plastic bucket, the opportunity for micro-oxygenation is there.

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Fermented in a Better Bottle.

I know that HDPE buckets are somewhat oxygen permeable and not suited for long-term beer storage, but I don't know about the Better Bottles. Perhaps someone can comment. Glass or stainless steel are better options for long-term storage.

mabrungard said:

Nope, doesn't take much at all. Micro-oxygenation is helpful for inducing brett to throw a little acetic acid into the mix.

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interesting, that contradicts what i've read. time to do some research...

mabrungard said:

I know that HDPE buckets are somewhat oxygen permeable and not suited for long-term beer storage, but I don't know about the Better Bottles.

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if you believe the research done by BB, the O2 permeability of BBs is negligible: http://www.better-bottle.com/technical.html (click the "Permeability" link on the left), http://www.better-bottle.com/pdf/CarboyPermeabilityStudy.pdf. Tonsmiere discusses in his American Sours book, need to look that up. seems like the take-home is that you're getting more O2 through the stopper and air lock than through the walls of the BB.

Thanks for looking into that. A quick search for oxygen permeability of polymers does indeed prove that PET has about 10 times lower permeation than HDPE. However, that permeation is dependent upon the thickness of the polymer. I'd say that a regular HDPE bucket is probably 2 to 3 times thicker than the PET Better Bottles, so the impermeability advantage of the Better Bottle is probably down to 3 to 5 times. Its still encouraging.

http://www.faybutler.com/pdf_files/HowHoseMaterialsAffectGas3.pdf

Going against my better judgement I tasted it again and it's worse
... Borderline vinegar. Any reason to ride it out or should I just dump it? I could use the fermenter for a new beer...

It will always be useful in blending, but if the acetic flavor is already high, it won't go lower. Its your call, do you have the space for this beer in your storage locker, is it worth keeping for blending? Are you interested in letting it go all the way to malt vinegar?

Brett3rThanU said:

I could use the fermenter for a new beer...

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then that's what you should probably do. this beer isn't going to get any better. like martin suggested, you could keep some for future blending if you think you'll get into that, but a gallon is probably more than you'll need.