16 replies to this topic

[bossbrew]

Well, here's the issue:Our club has an RIS project - 53 gallons in a Whiskey barrel. Started OK, but is definitely infected with acetobacteria. It's sour, but not undrinkable. Is there any way to stop the infection while it's still in the barrel? Maybe adding Campden tablets or ? Any thoughts...Dave

[strangebrewer]

Once acetobacter is in there I'm not aware of any easy ways of getting it out. About all you can do is minimize the the conditions that allow it to thrive. Keep the barrel topped up at all times, acetobacter needs oxygen so if you always keep the headspace to a minimum or none then you cut off one of it's requirements to live. Campden tablets (KMETA) can also help retard the growth of acetobacter but SO2 slowly dissipates and it is only slowing it anyway, not killing it. The final thing is temperature. Acetobacter reproduces rapidly above 62°F so if you can keep the whole barrel below 62°F you can keep acetobacter growth to a minimum.Depending on how bad it is your only other option is rack it and keg it to cut it off. Then you can steam the barrel to kill off the acetobacter that has taken up residence in the wood.

[chuck_d]

I guess the one thing that comes to mind is you can add a bunch of alcohol too it. I'm not sure what concentration you'd want to get up to to kill it off though

[chuck_d]

I thought acetobacter lives off of alcohol and oxygen?

Yeah, they oxidize sugars and alcohols, but I believe there is some level of alcohol that ends up stopping their growth. I guess I shouldn't have said kill it off, but I believe there is a concentration, around 20% maybe, maybe less, that stops them from growing. I believe the effect is enhanced but the hop acids present. Maybe I need to stop the PUI, maybe I'm thinking of something else. I'll have to dig into my notes tomorrow to see if I can find whatever it is I'm thinking of.

[djinkc]

Are you sure it isn't a lacto infection?Yes, I wrote infection Mtn

[MyaCullen]

If the beer is already done fermenting, which it sounds like and is just aging, why not add enough sulfite and sorbate to stabilize?

I tried that on an infected batch of Concord, it worked for awhile after a few months the aceto won the battle

[drewseslu]

Get that thing cold!Did you have a look-see under a microscope?

[MolBasser]

If you have acetobacter in a barrel aging project, prepare for some malt vinegar.MolBasser

[strangebrewer]

Yeah, they oxidize sugars and alcohols, but I believe there is some level of alcohol that ends up stopping their growth. I guess I shouldn't have said kill it off, but I believe there is a concentration, around 20% maybe, maybe less, that stops them from growing. I believe the effect is enhanced but the hop acids present. Maybe I need to stop the PUI, maybe I'm thinking of something else. I'll have to dig into my notes tomorrow to see if I can find whatever it is I'm thinking of.

Acetobacter is good to around 18%ABV. It's a mean little bug.

Are you sure it isn't a lacto infection?Yes, I wrote infection Mtn

YSYW.... uhhh I mean it's not an infection it's a contamination

Are you guys sure it isn't Brett? Brett makes acetic from glucose.

Brett can produce acetic and lactic but it does so in very small quantities. Acetic acid has a very very low PPM taste threashold so if Brett was a real acetic producer you'd taste it in most brett beers.

[bossbrew]

Wow, lot's of info. Well, yes I'm sure it's an acetobacterial infection. Fairly sour, and it has the dreaded scum. For now, I'll just add the Campden tablets (maybe 5 dissolved in pre-boiled cool water?) and try to figure out what to do after that. Maybe keg and use as a blending beer...Thanks!Dave

[lowendfrequency]

Unfortunately, that barrel is toast. The optimistic outlook is that you just got a new dedicated sour barrel. But until you get that beer out of the barrel, there is nothing you can do to permanently halt the infection.

[bossbrew]

Unfortunately, that barrel is toast. The optimistic outlook is that you just got a new dedicated sour barrel. But until you get that beer out of the barrel, there is nothing you can do to permanently halt the infection.

We kinda figured that...It's not a problem, it's an opportunity for a solution!

[lowendfrequency]

We kinda figured that...It's not a problem, it's an opportunity for a solution!

That's the spirit! Glass half full... with sour ale!

[MyaCullen]

Wow, lot's of info. Well, yes I'm sure it's an acetobacterial infection. Fairly sour, and it has the dreaded scum. For now, I'll just add the Campden tablets (maybe 5 dissolved in pre-boiled cool water?) and try to figure out what to do after that. Maybe keg and use as a blending beer...Thanks!Dave

don't quote me on this but IIRC a killing dose of Campden is 1 tablet per gallon, so unless your barrel is 5 gallons you'll need moreanyone else remember that dosage?

[MyaCullen]

1 tablet per gallon is 67 ppm SO₂ which is completely inadequate for this. I think 3 tablets/gallon (201 ppm) is more effective for this. The legal limit in the U.S. for wine is 350 ppm (5 tablets/gallon).

good info, now that I think about it 1 pet gallon is the racking dose on the packages

[chuck_d]

Acetobacter is good to around 18%ABV. It's a mean little bug.

There you go. I did a quick scan of my notes and didn't find that figure, but that's about in-line with the ~20% I was thinking. I mean, it'll totally change the RIS, but if your other option is vinegar then it might be worth several bottles of Everclear and a little work with the mixing formula...As someone else mentioned, it'd be worth taking a check under a microscope to see what's there.

[drewseslu]

I wouldn't use that barrel for anything other than vinegar, fire wood or a planter after this. Acetobacter will not yield a sour beer, it will render it into vinegar.