Fruit Flies + Airlock = bad?

So I was just perusing around here just now, and stumbled upon a bit of information that kind of worries me... fruit flies can lead to acetobacter infections? If this is the case, how exactly does this occur?

On my pumpkin ale I bottled a bit over a week ago, I noticed after coming back home after a few days away that a few fruit flies had somehow drowned themselves in the airlock (which was filled w/ san-star and water)... and now I am noticing on my bottles and Tap-a-Draft PET bottles that there is a faint line around the interface of the beer and air in the bottles. Is this just from the beer not moving for a week? Is it just CO2 built up or something? Or is this cause for concern? I recently had about half a batch of a brown ale go bad (lots of gushers, acetone aroma, consensus was a likely acetobacter infection), so I am really really not looking to go through this again so soon... especially with my pumpkin ale which i obviously brewed for the season.

There have been a lot of fruit flies around my house recently (damn spontaneously generating bastards!), and I would just like to know how these buggers can cause infection, and whether my brew is going to be ok..

In order for those darn flies to cause infection (I have them too, since we brought in all the tomatoes and apples from the garden), they have to have access to the beer/wine/cider. The fact that they are dead in the airlock is a good sign- it means that the airlock did its job and they didn't get into your beer.

If you're really worried, go ahead and sanitize a wine thief or a turkey baster and taste a sample of your beer. It's probably just fine!

cool.. i figured the airlock was doing its job, but man having an infection on that last batch just has me overly worried on sanitation now. So the lines in the bottled beer i described are ok too?

Yooper's right...

BUT how it works is that they carry aecetobactor on their little toesy woseies and when they land to take a drink of your sugar water, the nasty aecetorbactor is transfered, and if enough of it is present then in turns your beer/wine to vinegar.

bergman1118 said:

cool.. i figured the airlock was doing its job, but man having an infection on that last batch just has me overly worried on sanitation now. So the lines in the bottled beer i described are ok too?

Click to expand...

I would guess the lines are ok- I don't know if I've ever noticed something like that in mine, but I don't look very closely at the beer. It could be just from sitting, I would think.

I guess that's another nice thing about plastic buckets, and kegs- I can't see inside of them so I don't worry if it tastes ok!

well, time will tell i suppose. next thursday will be the 2 week mark and i always try a bottle then.. nothing else to do in the mean time except RDWHAHB! that and figure out where all these damn fruit flies are coming from.

Here is how to get rid of the fruit flies -

mix some dish detergent in a bowl of water.

Then add red wine.

Flies will beatte=racted to wine, but will fall through water bec soap has killed surface tension of the water...

I saw this solution in the produce section of the local food market -- it WORKS!

wow that's simple and makes perfect sense. i'll have to try that b/c they are driving me crazy right now

If that doesn't work, a nice carcinogenic BUG BOMB will nuke those suckers. I got a bunch of them from some bannans I bought at a farmers market.

dont' worry about the bubbles in the bottles, some beers just have more protein that causes bubbles. In fact, it's probrably a good sign because it indicates that the beer will (probrably) have a good head.

10/10 for putting Starsan into the airlock too. The number of people that use plain tap water and risk infection by the airlock being sucked back (when cooling before racking for example). An alternative is to use Vodka or Bacardi if you don't have a decent no-rinse sanitiser to hand. Just don't use plain water, it's not worth the risk.

Protip for handling fruitflies that I got from a fruit fly researcher:
make what pretty much amounts to a small starter (sugar and yeast) in a jug or something similar, and instead of an airlock, use a funnel. The flies will be more attracted to an active fermentation, and they won't be able to figure out how to crawl out of the jar.

The way i get rid of them is to peel an apple, cut it in half and place it in a bowl. Then pour wine over it until it is half way covered with wine.

Cover the bowl tightly with 2 layers of saran rap and poke holes in it with a fork. The flies will all be trapped inside in no-time.