Fruit Flies in beer bottles

After seeing what appeared to be a very small larvae (millimeter or so) I have been seeking to discover what could possibly be in my beer, and I mean a full capped bottle of beer. Finally, after days of googling larvae in beer I looked up fruit flies and found that fruit flies not only eat yeast and are attracted to CO2, but also have an alcohol tolerance.

If anybody else has heard of such a thing I would love to hear about it.

That is creepy. Did you open ferment?

just 1 bottle? or more... If 1 probably a freak (although gross) incident. more than 1... you have some Sanitation/Fly issues.

Yup, stupid things are always all over the place. Best thing to do is to keep a trap for them. Which is pretty much a cup of soap and beer (or cider vinegar) and perhaps some water as well as a downspout so it's easier for them to get in than out. This way, the fruit flies trap themselves and drown in the liquid.

Haven't had them in a bottle, but I'm 90% sure I had them in a keg. Dumped the entire thing and it smelled badly of vinegar and had werd things in it. I think it flew in while I was transferring because it was fine from the primary.

We had some fruit flys a couple years back. We just set out a bowl of cider vinegar for them and after about a week the problem was solved.

I didn't know that they were attracted to co2, but it explains a lot. When we had them (anyone who's had them knows that they're like an infestation when you get them), they would always be in the airlocks of my brews. The airlocks were full of cheap vodka, so they died in there and didn't make it to the brew, but it grossed / freaked me out and led to a very thorough inspection of a carboy for about an hour.

I had it happen today to me today. Played out like this.......someone that I gave a beer to to enjoy said why does this beer stink and what the hell is this stuff floating in here? I said bull**** give me that beer, i smelled....yuck, and i looked....WTH little floaty things.

I felt so stupid and mad at the same time. I didn't know what had happened because I made two cases and drank almost36 of the 48 bottles and nothing tasted bad at all. Now one bottle is all funked up, HOW???? It had to happen at the time of bottling due to it was in only one bottle. Didn't know this could happen till I googled it, got on this forum, and looked at them under a microscope at work. Yes I took a sample to work and made a slide and saw those lil bastards up close. Now I can say, lesson learned, thank God it was only one bottle, and I got my eye out for them now, game on.

A small bowl with cider vinegar and a pump of dishwashing soap mixed up will attract and kill them easily. Put that out in an area where you think you might have them.

Hanso said:

That is creepy. Did you open ferment?

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Nope, primary to secondary carboy to bottling bucket to bottle. Figure it must have flown into the bottling bucket that was open.

Ended up being several of the bottles but not all of them, I think that the some flew into the open bottling bucket and laid eggs.

bmick said:

I didn't know that they were attracted to co2, but it explains a lot. When we had them (anyone who's had them knows that they're like an infestation when you get them), they would always be in the airlocks of my brews. The airlocks were full of cheap vodka, so they died in there and didn't make it to the brew, but it grossed / freaked me out and led to a very thorough inspection of a carboy for about an hour.

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I read up on it and found out that they are actually attracted to alcohol and can even live on the fumes of alcohol if no other food is available. It has to do with scavenging on rotten fruit that has started to naturally ferment.

Another solution is to get an old bowl/container, put about a 1/2 cup of orange juice in it, a banana peel, then cover it with saran wrap. Poke small holes in the saran wrap.
They'll get in, but can't get out. Just make sure you keep an eye on that bowl and empty it regularly.
It WILL catch them and then they'll multiply in there.

inwildness said:

After seeing what appeared to be a very small larvae (millimeter or so) I have been seeking to discover what could possibly be in my beer, and I mean a full capped bottle of beer. Finally, after days of googling larvae in beer I looked up fruit flies and found that fruit flies not only eat yeast and are attracted to CO2, but also have an alcohol tolerance.

If anybody else has heard of such a thing I would love to hear about it.

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This is caused by fruit flys laying eggs inside your used beer bottles then you filling the bottles later.

Time flies like an arrow. Fruit flies like a banana.

capcrnch said:

Another solution is to get an old bowl/container, put about a 1/2 cup of orange juice in it, a banana peel, then cover it with saran wrap. Poke small holes in the saran wrap.
They'll get in, but can't get out. Just make sure you keep an eye on that bowl and empty it regularly.
It WILL catch them and then they'll multiply in there.

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Good lord. I have to admit I like the cider vinegar bowl better so you catch, kill, discard instead of worrying about multiplications. egad.

Your beer has spontaneously created life..........impressive.

Supurb said:

Your beer has spontaneously created life..........impressive.

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Well said!

One of my favorite threads ever: https://www.homebrewtalk.com/f14/yellow-white-creepy-crawly-things-my-beer-130714/

Yech!

inwildness said:

After seeing what appeared to be a very small larvae (millimeter or so) I have been seeking to discover what could possibly be in my beer, and I mean a full capped bottle of beer. Finally, after days of googling larvae in beer I looked up fruit flies and found that fruit flies not only eat yeast and are attracted to CO2, but also have an alcohol tolerance.

If anybody else has heard of such a thing I would love to hear about it.

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Actually read an article in some rag about a study in which male & female fruit flies were controlled in an effort to breed in an environment containing a single source of alcohol, beer. The male flies would pursue the females, and after failing to mate with their chosen one, would,rather quickly, go to the alcohol and, hilariously, drown themselves in beer. Literally consume so much they die. Right there in the beer. Think about that the next time you find dead fruit flies in alcohol. Lonely Hearts Club. HA HA HAAAAAAAA!!!!!!

crushingblackdoom said:

Actually read an article in some rag about a study in which male & female fruit flies were controlled in an effort to breed in an environment containing a single source of alcohol, beer. The male flies would pursue the females, and after failing to mate with their chosen one, would,rather quickly, go to the alcohol and, hilariously, drown themselves in beer. Literally consume so much they die. Right there in the beer. Think about that the next time you find dead fruit flies in alcohol. Lonely Hearts Club. HA HA HAAAAAAAA!!!!!!

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I think that article was in the NY Times! I saw it too.