SDMB Brewers: name that contaminant!

Ok, having a problem. This happened with several batches last year, but this year (different apartment but closeby) we’ve been ok until now, until the last batch.
Sanitation: pretty good. Working from extracts with a tad of grain for flavor steeped first. Water filtered through carbon. Additives: Irish moss. 3/4 c dextrose for priming.
Now, everything goes fine through primary and secondary, but then! Something happens at bottling (24 oz bottles, sanitized with one-step). A tart or sour taste enters (not particularly cabbagey, band-aidy, or sulphery, more like off-citrus?), which gets increasingly strong the longer it’s in the bottle. Doesn’t carbonate well, either.
Any thoughts? The troubleshooting in my beer books doesn’t list anything exactly like this.

Don’t know what it is but I know what to do about it. Relabel it as a lambic and get snoby when people complain that its sour. They’ll think your a pro.

Me too, or Me neither. Use a generous heap of MaltoDextrin in the boil, dry-hop big in the secondary, use cornsugar to bottle. Never have a tart brew again.

Computer fart. Double post

I would guess that your brew is suffering from a bacterial infection–possibly acetobacter, which produces acetic acid. If so, the brew will start developing a vinegar flavor. If it’s not a vinegary sourness, it might be lactobacillus, or any number of other bacteria.

Here’s a nifty quick-reference on Beer Faults I stumbled across. It doesn’t specify particular types of infection or how to check for them, though.

I don’t know if there’s anything you can do about your current brew except, as Christopher said, relabel it :). The best course for the future is probably to be really fanatical about sanitizing all of your brewing equipment.

Disclaimer: I neither brew nor drink beer–I make mead and wine, mostly.

Yep. A citrus-y taste is a sign of bacterial infection. Check your hoses and general sanitation procedures. Replace all airlocks and stoppers. Examine secondaries for scratches, replace as needed. Dump the batch and bottles.

Alas. Ok, I’m sort of thinking that lactobacillus is a good option, because it does remind me of the lambic tart more than anything (and I recall that it’s added purposefully to some of those?) (I wonder if I’ve spent so much time drinking the stuff in Belgium that lactobacillus and Bruxellensis yeast exudes from my pores? Rodenbach’s one of my favorite beers… .). So sad.

Consider yourself lucky. The one time my equipment got contaminated it was by a slime mold, which turned 2 batches into something resembling 10W-30, and about as appetizing. I had to totally replace my whole system (well, everything post-boil.) I didn’t trust any of it.

Paging August West.

What, you don’t trust my credentials as a homebrewer? I’m BJCP Certified, I am! :smiley:

Tart like a green apple? It could actually be the cornsugar used at bottling. Try using extra light dry extract instead, I’ve been having better luck with this instead.

I know, but Augie is a homie of mine, and works in the industry. Gotta give him his chance for input! You don’t rely on me only, do you? I always like to have karlGauss and Doc_Paprika and DoctorJ chiming in too!

How are you adding the priming sugar? Are you adding to some water, and bringing to a boil (then cooling) prior to adding to the bottling bucket? If not, you may be introducing an infection via the corn sugar.

Sanitation - there is no “pretty good.” There is do, or do not. </Miagi> Get a good sanitizer and do it right. (You’re using one step, are you using the correct concentrations?)


My advice is always the same when it comes to identifying spoilage organisms. It doesn’t matter.

To expand on that, it doesnt matter what the spoiler is, the mere presence of a spoiler indicates a breakdown somewhere in your sanitation procedure. All of the steps silenus laid out are a good start.

Since it only seems to be appearing in the bottles I would tear apart your bottling system and re-examine your bottle sterilizing technique.

I suspect I’m not using enough of the one-step. It occurs now to me that the problem only happens when I and not my spouse cleans the bottles. . . Me: “How much of that stuff do you use?” Him: “A shitload.” I don’t think I use a shitload. So I look on the thing for suggested concentrations and think again about how much a liter is and how much a teaspoon is and think “Oh. Hell.”

So what’s everyone else currently brewing?
I’ve got:
a “Fin du Monde” clone aging in the bottle for about a month so far
a blueberry wheat in the secondary; should be ready for kegging in 2 weeks or so
and a “Fat Tire” clone in the primary that was brewed on Sunday.
There was a light ale after the Trippel and before the wheat ale, but it was kegged and already consumed!

I have another batch-- a wheat-- ready to head into secondary. I’ll be more careful with the bottles this time. . .

It matters to me. I love lambics, and intend to add these little beasties on purpose. If I were you I would let it sour a bit longer, maybe a full year. Yum yum.

Christopher, I wouldn’t be so sure that the spoilage organism in capybara’s beer is going to make a nice tart gueze. It could just as easily turn into big ropy strands of slime.

Just calling any contaminated homebrew a “lambic” is an old joke in homebrewing circles, but it does a bit of disservice to the style.

For a good lambic you really need all the cultures. Brettanomyces bruxellensis in particular.