acetobacter?? time to throw out the plastic.

[slanted & enchanted]

i brew with three other guys so we try and max out our converted kegs every batch, which means we'll drain about 13 gallons out of the mash tun when we brew. we can't afford, or really, can't JUSTIFY spending the money on a conical so for the last 18 months we've been using these big 20 gallon plastic fermenters, i think they cost like 30 bucks a pop. we brew so much we use two and always seem to have a few carboys full as well.

anyway, the last two beers we fermented have a slight tang, but man, the fermenter smells like i poured vinegar up my nose. horrid! so we got the kegs chilled up really quick, and the beer is drinkable with just an ever so slight tang to it. i figure the fridge temps will slow the growth of the acetobacter and if we can drink it in a reasonable amount of time we won't have to drink malt vinegar.

anway, what causes this? these fermenters are not air tight, they're like trash cans with lids. i'm sure they're scratched all to hell (they look fine, but microscopically they have to be a mess). thirdly, it's hot as all hell outside, and although i have a temperature controlled room there's proably a lot more bacteria floating around directly outside it.

so what do we do? personally i'd like to move to something airtight first. we'll probably move back to carboys but it sucks to sanitize and ready 3 every time. then theres the conical, which is probably not an option.

what's a good, reasonably priced, airtight, high-volume (10-20 gallon) fermenter that's available out there?

[SacoDeToro]

Acetobacter causes acetic acid in beer. It's an aerobic bacteria that typcially grows in finished beer that gets exposed to air for extended periods of time. I'm guessing that the porous plastic in your fermenters allowed funk to build up over time. The porosity of the plastic also allows O2 to diffuse through the plastic, even with an airtight lid. The diffusion rate is a few orders of magnitude higher than a carboy with with a silicone hood and airlock. This is one reason why it's recommended not to use plastic buckets for long term aging of any beers.

[Thirsty Boy]

I left the dregs in my plastic fermentors a few times - after a week or two, there were plenty of acetobacter in full flight.

Clean plastic fermetor - soak for a couple of days in a strong acidified bleach solution (30ml of bleach into a litre of water then after the bleach is well mixed in, 30ml of vinegar - scale up as required) this is heaps stronger than the quite dilute 30ml per 19L solution that you would normally use as a no-rinse sanitiser. But it does nuke everything in site. This strength of acidified bleach will take out anthrax.

Rinse very well and sanitise as normal before brewday.

No reason to throw those fermentors out, just give them a really really good sterilise and they should be fine.

Thirsty

[Bugeater]

Fruit flies are notorious carriers of acetobacter. It is important that you keep the brewery extremely clean of spilled extract, wort or finished beer so they are not attracted to the area. You need to get rid of those little bastards before you expose any more beer to the air.

Wayne
Bugeater Brewing Company

[slanted & enchanted]

bug, i just read your post on zee's thread about fermenters. i may try the plastic bag idea. actually, here's my plan.

we're stepping up to a 55 gallon drum system soon (which is VERY relative, think sooner than pigs fly out my ass). i think for fermentation i'm going to use a 55 gallon plastic drum, line it with a 4 mil food grade drum liner, and pull the open end up through the larger bung. then cap it with a big stopper and airlock.

when i need to transfer, i can hook up my air compressor to a hose in the small bung and force the beer out through a racking cane. the air is going into the drum but not into the bag, so it's basically just squeezing the bag empty.

then i throw out the bag or knot it up with the yeast and throw it into the fridge for the next session.

the only bad thing i can think of is the compressed air getting the yeast back up into suspension. but i guess i could run the beer through a filter to fix that.

that, at least in my head, sounds pretty darn reasonable.