Infected beer

[davejhs]

Have just thrown away my latest AG brew.
Was a brown recipe from greg hughes book.
Should have ended up at 3.8 ABV.
It had a vinegar smell and tasted awfull after being in FV for a week.
This is my first failure.
Are lower ABV beers more susceptible to infections as all my previous stronger brews some ending up at 6.5 have all been ok.

 

[MyQul]

Technically yes as alcohol is a hostile environment for microorganisms. But I regularly make 3.5%-4% ales and I've only had two infections, due to my own fault of opening the FV before the end of fermentation. Before and after fermentation I have the FV open quite a bit (aeration, racking, etc)

 

[Wardy]

They shouldn't be. It just seems like bad luck to me. The yeast would be just as active in the first 48 hours in any brew but would drop off and finish quicker once the fermentable sugar was in short supply.

 

[davejhs]

I will put it down to bad luck.
I suppose that most brewers will have a bad one.

 

[Hoddy]

I've had an infected batch when using a liquid yeast. The yeast might not have been stored not that well, and it could have been towards the back end of its shelf life. What I've found is that because the yeast is not good it doesn't start as fast as it should. And as such it doesn't drop the ph quick enough to stop and bacteria to form.

But as well know, sanitise, sanitise, sanitise!!!!!

 

[MyQul]

I've had an infected batch when using a liquid yeast. The yeast might not have been stored not that well, and it could have been towards the back end of its shelf life. What I've found is that because the yeast is not good it doesn't start as fast as it should. And as such it doesn't drop the ph quick enough to stop and bacteria to form.

But as well know, sanitise, sanitise, sanitise!!!!!

Did you not make a starter?

 

[duncans]

Unlucky, fella.

Last infection I had turned into a run of infections. Bleaching all the kit and chucking out cheaper plastics broke the bad run.

 

[Hoppyland]

It had a vinegar smell and tasted awfull after being in FV for a week.
This is my first failure.

Hmm - well, can't see why it would have a vinegary smell after only a week. On the other hand, I'd expect any beer to taste pretty awful after just one week!
Did it ferment vigorously to start with?
As I understand it, acetic/vinegar spoilage is a secondary "fermentation", where certain bacteria convert alcohol to acetic acid in the presence of oxygen.
So, if your beer gets off to a fast & furious start & is throwing CO2 all over the place, as it should, then the acetic acid nasties aren't going to get a look in.
Alternatively, if you had little activity to start with, then there might be still be oxygen, but there shouldn't be much in the way of alcohol after a week - hence no conversion to vinegar. Puzzling.
Did you take a SG reading before you dumped it?
What temperature were you fermenting at - high temps can produce weird flavours with certain yeasts.

 

[geetee]

Never yet had a bad batch through infection in 8 years or so and I must say I am always lifting the lid on the FV and even dipping a sample glass (scoured with boiling water first) to check PG. Also often removed dry hop bag and squeezed it with my hands but still no infection so I guess I must just be lucky?

Now that I have said that.................I'll keep you informed if I get one soon!

 

[Hoppyland]

I guess I must just be lucky?

Unlikely, I think. (Although I haven't won the Lottery in the last 8 years - maybe I'm the opposite - serially unlucky???)
No, my guess is that you're brewing in a relatively safe environment. Not in the proximity of fruit-flies etc. Hell, if you sterilise your sampling glass in boiling water, then you must be on the lookout for possible infection routes.
I also use my hands to squeeze hops etc, but if your hands are well cleaned then a problem is hugely unlikely I reckon, as long as you keep air away from the late fermentation and maturation stages of beer as far as possible.

 

[Sandimas]

Last infection I had turned into a run of infections. Bleaching all the kit and chucking out cheaper plastics broke the bad run.

I've got one of those at the moment - 6 brews infected since last summer after 4 years and 80 odd brews with no infections :-( Seems to have got into the plastics, at least 1 FV and 1 barrel are infected despite liberal cleaning and application of VWP, now trying bleach.

 

[GHW]

I've not had an infection but when I thought I did I immediately replaced most plastic stuff, fvs, siphons, paddles etc. You can replace most of it for under £20 which for me at least was worth the peace of mind and avoiding the misery of a run of bad brews.

 

[duncans]

Forgot post his. Amazing if you use small demijohns..
http://www.amazon.co.uk/dp/B00I3HXS60/?tag=skimlinks_replacement-20