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View Full Version : how do you know a batch is infected?

ehixon
10-12-2003, 10:41 PM
Out of curiosity, what are the tell tale signs of an infected (bacteria or otherwise) batch of beer?

I'm pretty new at homebrewing (just bottled my 4th batch today and have my 5th in the seconday fermenter as we speak). I'm quite sure none of them have been infected as they aren't doing anything "unusual" per se...just curious as to what the symptoms of a bad batch are.
Beerconnoisseur
10-13-2003, 12:44 AM
From what I've read, if you see a bacterial infection, it will usually appear as long, stringy strands, almost like seaweed. You might also notice vinegar/sulfury smells or tastes. Mold can also infect batches (as white/brown/green stuff), but sometimes the batch can be saved if it is caught early enough.

The best solutions are, keep everything clean & sanitized, and pitch a healthy yeast strain (making a starter as necessary). Once the yeast starts converting sugar to alcohol, it will inhibit the growth of most mold/bacteria.

Oh, and read Palmer (http://www.howtobrew.com/section4/chapter21-1.html) for more info on brewing issues. Pretty good online resource, and the price (free!) is right...
ehixon
10-13-2003, 01:43 AM
ahhh. cool. Most people that I asked about this just said "oh, you'll know" and wouldn't elaborate- leading me to think that they didn't know but wouldn't admit it. :p

by the way, what/where is this Palmer that you speak of?

just saw that you linked to it...doh. Thanks!
mortong
10-13-2003, 02:36 AM
Originally posted by ehixon
"oh, you'll know"


One of the drawbacks of the internet is lack of tonation and expressions you get in face to face. Imagine that phrase said ominously, and it's probably more what they meant. ;)

Most people I asked face-to-face about it said much the same thing in that way - but then went on to say what Ehixon said. As I understand it, if it gets infected you will know - It'll smell, taste and look awefull.
ehixon
10-13-2003, 02:40 AM
well, up to now all the people I did ask were in person and none of them would elaborate so I just assumed that none of them had actually had a batch go bad.

oh and that Palmer site is great- I think I found out why the Belgian white that I made had a kind of "vodka" like flavor- from ahving been made in the summer ina n apartment with crappy AC. oops! the temp was a little high.
brewmonkey
10-13-2003, 06:14 AM
Not all infections will have a ropey appearance, and when that does occure it is usually in the severe cases.

Infections will come across as different aroma or flavors depending on what caused the infection. Some bacteria will cause diacetyl (butter/butterscotch) others will present as acetic acid (Vinegar) and so on. There are gram negative (E. Coli) and gram positive bacteria (lactobacillus & pediococcous) and each will have a negative effect on beer.

While I agree in pitching healthy yeast and the proper amount, it will not inhibit the growth of any bacteria present. If bacteria is in the wort at pitching time, it will grow on par with the yeast and overtake it in the process sending your beer into the gutter.

In addition to bacterial infections there are also wild yeast issues that can cause an off flavor in beer. Wild yeast is in the air and on all things around us, and will vary by region/country.
Beerconnoisseur
10-13-2003, 04:53 PM
Originally posted by brewmonkey
There are gram negative (E. Coli) and gram positive bacteria (lactobacillus & pediococcous) and each will have a negative effect on beer.

Unless, of course, you're trying to brew a lambic. In which case, you'd want a completely different set of fermenting/bottling equipment, anyway, to avoid contaminating your non-lambic beers... :p
priceposey
10-13-2003, 06:40 PM
i have a question that fits here.i just bottled my 1st batch today and noticed that it smells kinda funny,is this normal?im i just paranoid?

price
Beerconnoisseur
10-13-2003, 06:58 PM
Originally posted by priceposey
i have a question that fits here.i just bottled my 1st batch today and noticed that it smells kinda funny,is this normal?im i just paranoid?

price

It probably is normal; I'd wait the two weeks, bottle it, and take a taste two weeks after bottling. The smells can really vary, in my experience, even if the beer is fermenting perfectly normally (for example, an ale hopped with Cascade hops might have a 'piney' smell to it). Wait and see; your beer will tell you soon enough what you did right, and wrong. Oh, and use the Palmer link to diagnose specific problems...
brewmonkey
10-13-2003, 06:58 PM
When you say it smells funny how would you describe the smell?
priceposey
10-13-2003, 08:34 PM
Originally posted by brewmonkey
When you say it smells funny how would you describe the smell?


thanks for the iinput Beerconnoisseur.


I guess i wouold say a spoiled smell.
brewmonkey
10-14-2003, 07:54 AM
WHAT is the smell. Sorry but funny and spoiled wont help us determine the root of the infection/problem.

Does it smell like rotten eggs (Sulfury), like vinegar (Acetic acid), bandaids (phenolic) etc....

What is the actual smell or taste you are getting from this beer. Each off flavor/aroma can be linked to a specific problem and from their we can determine what is the cause.
emenzer
10-14-2003, 09:56 AM
I am in the same situation. In the secondary and will bottle in a week. My beer smells very strong alcoholic like. It doesn't smell like beer at all. What might that be attributed too????
brewmonkey
10-14-2003, 11:36 AM
Originally posted by emenzer
I am in the same situation. In the secondary and will bottle in a week. My beer smells very strong alcoholic like. It doesn't smell like beer at all. What might that be attributed too????

Higher alcohols. What was the temp of your fermentation?
emenzer
10-14-2003, 12:05 PM
the fermentation temp for the first 3 days was at 72degrees. It was never over 80 which I understand can yield high amounts of fusel alcohols.
ehixon
10-15-2003, 01:22 AM
the temp thing explains why my last two batches had such an alcoholoc smell/flavor. That was definitely a problem for me with the Hefeweisen I made- the AC in my apartment is terrible :mad: I guess as long as I live here I'll try to keep my summer brewing to a minimum.
brewmonkey
10-15-2003, 06:34 AM
It depends on the yeast strain. While 72 is not very high it is about 4 degrees above optimum for a majority of the ale strains and is enough for fusel oil production.
kevin
10-15-2003, 07:01 AM
Originally posted by brewmonkey
fusel oil production.

what does fusel oil taste like, because I brewed an octoberfest and during the primary stages the temp went soaring for about 4 days. well now I've had the beer bottled for about 3 weeks and the taste is a cross between cider and beer. It's drinkable just very different in taste.
ehixon
10-17-2003, 02:32 AM
kevin from what I understand, the fusel taste is like a strong alchohol flavor...like someone put bad vodka in your beer.


you know...it's ironic that I ask this question- just days after I posted this I'm thinking (hopefully not being a hypochondriac here) that my latest batch is crapped up. It's now closing in on a week in the secondary (after a week in the primary) and it's not even close to settling down...it's very "active"....there is not a lot of bubbling in the airlock, but if you look closely you can see particles "churning" sort of...like a snowstorm in the beer itself.


I suppose I'll sit on it a while...things were going pretty well previously...there are no obvious visual signs of anything bad and I don't think it smells bad...I'd love for someone to talk me into feeling better about this batch :p but from everyting I've read things should be slowed down by this point.
evilredlight
12-23-2003, 08:02 AM
maybe its a poltergeist