Contaminated? Should I dump it?

[Dangerous]

Hey everyone. I’ve been fortunate enough to have brewed 24 batches with no contamination...until now. Everything was fine while it fermented for 3 weeks but I did notice a faint film when I finally checked the gravity. I checked the gravity once more the following day and haven’t touched it since. Now, 4 days later, the film has grown and I suspect the worst.

I’ve never seen anything like this so I’m not sure how bad it is. I’m ready to bottle but should I even bother? Thanks for the help.

-D

 

[S-Met]

How does it taste and smell. The "infection" only means wild yeasts took hold. Doesn't mean that its bad.

 

[Amadeo38]

Taste it for sure. Most likely it will have a slight barnyard or phenolic taste, if any, and the pH of the beer may be just a bit lower than it would have been otherwise, which isn’t necessarily always bad. If that’s a stout, a lower pH might give it a Guinness-like quality.

As far as what to do next, if you’re bottling, be sure to really do a good job cleaning your plastics afterward with plenty of hot PBW and a good Star-San/ iodophor soak. If those plastics have cracks or your tubing is old, consider taking this opportunity to replace it. I get fresh plastics about once per year just to be safe, which equates to about 20-24 5-gallon batches. Also, if as soon as the beers have reached your desired carb level, consider cold storage to slow down any further wild yeast development.

 

[frankvw]

Agreeing with the above posters who suggest that you check smell and taste, I have always been of the opinion that unless you are 100% certain the beer is contaminated to the point of not being salvageable, you might as well bottle. I've had several weirdly tasting beers that after a few weeks in the bottle came out quite nice. So when in doubt, bottle. You can dump it now or later, but if you dump it later it may come right before you get there.

Just one warning: bacterial infections can easily lead to overpressure and 'bottle bombs' so let you beer mature somewhere safe and open a bottle after a week to see if you have a gusher. If you do, dump the batch immediately. Safety goggles never go amiss when dealing with potentially overpressurized bottles.

 

[Dangerous]

Thanks all for the replies. It’s great to get feedback from people who’ve been there before. Lots of good advice here.

I’ll definitely taste it today and bottle if it’s not too bad. I’m not terribly picky and as long as it tastes like beer I’m happy. I’ll also be sure to watch for the infamous bottle bombs.

Washing my gear is something that I don’t think I’ve ever done. I just rinse it all off, spritz it with some San star and chuck it in an open bucket until next time. I was wondering what all of the fuss was about sanitizing and it seems I may have been taking it too lightly. My car boys, buckets, tools, tubing...everything have never been washed. I’ll take care of that today before bottling. Thank you Amadeo for that great revelation. Moving forward I guess everything gets washed after using it.

Thanks again to all my brew brothers and sister who read my post and helped me out. Wish me luck and brew on.

-D

 

[RPh_Guy]

Want to add: Don't scrub plastic with anything abrasive. Micro-scratches can harbor microbes.

+1 for warm PBW soak.

bacterial infections can easily lead to overpressure

Yeast, not bacteria.

 

[frankvw]

Yeast, not bacteria.

Certain bacterial infections can also cause overpressurized bottles.

 

[RPh_Guy]

Certain bacterial infections can also cause overpressurized bottles.

Which ones?

 

[frankvw]

Which ones?

E. Coli, for one. Granted, consuming sugar is not its preferred metabolic mode, but if they end up in a beer and has no other option, it will, and produce CO2 in the process. (It will produce other waste products as well which are immediately recognizable as digestion waste products, so if you've got an E. Coli infection you'll smell it, trust me.)

 

[RPh_Guy]

E. Coli, for one.

E. coli does not grow in beer because of the alcohol, so no, it will never be the cause of over-carbonation.

Any others?

It's a short list of microbes that will grow in beer and none of the bacteria produce significant amount of CO2.
Only yeast are capable of over-carbonation: Saccharomyces cerevisiae var diastaticus and Brettanomyces spp. are the main two.

 

[Tbagger]

I'm surprised no one has mentioned this but it looks a lot like the beginning of a pellicle "infection" which can give you a really nice sour. Let it ride and see what happens. Maybe add some Lactobacillus or Brettanomyces along with some fruit. Might as well go with it, since no matter how much you clean it that carboy, chances are it will only make sours from here on out.

 

[RPh_Guy]

I'm surprised no one has mentioned this but it looks a lot like the beginning of a pellicle "infection"

It is definitely a pellicle.

which can give you a really nice sour.

"Can" is the operative word. More likely is that leaving it sit for months would ruin the beer. Oxidation will set in and wild microbes usually do not produce desirable flavors in beer.
If the OP wants a sour I would suggest following a recipe for one. This beer I recommend packaging now if it tastes fine.

no matter how much you clean it that carboy, chances are it will only make sours from here on out.

Cleaning equipment isn't that difficult. Following some basic practices will ensure that future batches aren't contaminated.
Break things down. Soak in percarbonate. Rinse.

Cheers

 

[Tbagger]

Cleaning equipment isn't that difficult. Following some basic practices will ensure that future batches aren't contaminated.
Break things down. Soak in percarbonate. Rinse.

Cheers

Haven't had much luck going back and forth between sours and regular beers using the same cold side equipment. Sometimes I can get a batch or two in but the sours always start back up. I have used oxi, PBW, BKF, vinegar, IPA, bleach, etc. So now I have dedicated sour equipment and haven't had a problem. And before it's mentioned/asked, I am meticulous about my sanitation and have never had an unintentional infection in my 10+ years of brewing outside of using equipment that was previously used for sours.

 

[RPh_Guy]

That's fair. YMMV. However, a lot of us are successful cleaning our equipment.