Author Topic: Fruit flies in airlock  (Read 3106 times)

cornershot

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Re: Fruit flies in airlock
« Reply #15 on: October 10, 2013, 08:17:30 AM »
I fish them out of my glass frequently and haven't noticed any funky tastes.  Lately there's been about two per pint that land in my glass particularly if I'm sitting in the yard.  Maybe I need to drink faster.

Or drink from a lidded stein!  :)

Offline majorvices

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Re: Fruit flies in airlock
« Reply #16 on: October 10, 2013, 09:17:44 AM »
At what point would you all be concerned with a fruit fly caused infection? I had one little demon fruit fly crash into my rehydrated yeast this weekend and instantly drown I pulled him out, but pitched the yeast anyway. I had no other yeast option other than bread. Its a Saison fermenting at 75. Fermentation was active in only 3 hours.
Surprisingly, the fruit flies are avoiding my carboy.

So you knowingly pitched a vinegar fly into your wort? Sorry, but there's no way I would do that! They're covered with acetobacter.
Just one fruit fly will instantly give a funky taste to a glass of beer. I drink from a lidded stein in fruit fly season.

But acetobacter requires oxygen, so assuming fermentation starts quickly and oxygen is kept out after - one fruit fly probably won't have an effect. I'm suspicious about one fruit fly turning a glass of beer funky. That one might be all in your head. There just isn't enough time for acetobacter to turn beer unless it sits for a few days.

I'm not saying it's a big concern, but I wouldn't do it. That fruit fly would, at the very least, be in my head right down to the last pint. I certainly wouldn't repitch the yeast!
And I have noticed an off flavor halfway through a beer only to discover a fruit fly upon further inspection. My wife and several friends have also noted this phenomenon.

I'd use the yeast. You will out compete any funky if it's a starter. I probably wouldn't reuse the yeast.

As far as "one fruit fly getting in your beer causing an off flavor" .... I'm just gonna say that has to be in your head. There is no way a beer can get infected that fast. I'd be willing to do a taste test with you to see if you could pick out the "funky" beer.
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Offline bluesman

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Re: Fruit flies in airlock
« Reply #17 on: October 10, 2013, 09:40:03 AM »
I think that the odds of infection from one fruit fly prior to fermentation (assuming sound sanitation practices) are slim to none. The competition for O2 by the yeast would likely win out.

As far as tasting acetobactor. I think the taste threshold for acetic acid is roughly 150-200ppm. So imagine the effects of one fruit fly in your beer. I can't imagine that it would noticeably sour your beer. Perhaps stranger things have happened, but...
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Offline jeffy

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Re: Fruit flies in airlock
« Reply #18 on: October 10, 2013, 01:44:40 PM »
I bottled some mead in clear nip-sized bottles for a competition last weekend and while packaging them for shipping I noticed a tiny ant floating in one of the bottles.  I doubt it will affect the taste, but it might have turned off a judge at the table.
Funny, these bottles were rinsed after first use, rinsed again after storage, sanitized in starsan, drained well and put into the freezer before filling from a keg.  I can't figure out where the little guy had a chance to get in there.
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Offline erockrph

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Re: Fruit flies in airlock
« Reply #19 on: October 10, 2013, 02:52:17 PM »
I bottled some mead in clear nip-sized bottles for a competition last weekend and while packaging them for shipping I noticed a tiny ant floating in one of the bottles.  I doubt it will affect the taste, but it might have turned off a judge at the table.
Funny, these bottles were rinsed after first use, rinsed again after storage, sanitized in starsan, drained well and put into the freezer before filling from a keg.  I can't figure out where the little guy had a chance to get in there.

Ants are tasty. They have a nice kick from the formic acid in their abdomen. It would probably compliment a lambic quite well.
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Offline Steve in TX

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Re: Fruit flies in airlock
« Reply #20 on: October 10, 2013, 03:12:10 PM »

[/quote]

I'd use the yeast. You will out compete any funky if it's a starter. I probably wouldn't reuse the yeast.

As far as "one fruit fly getting in your beer causing an off flavor" .... I'm just gonna say that has to be in your head. There is no way a beer can get infected that fast. I'd be willing to do a taste test with you to see if you could pick out the "funky" beer.
[/quote]

I agree. I have made vinegar, on purpose, and even with a decent sized pitch of aceto culture, it take about 1 week per 1% of alcohol to do it's thing. Just my experience.

cornershot

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Re: Fruit flies in airlock
« Reply #21 on: October 10, 2013, 05:18:55 PM »
At what point would you all be concerned with a fruit fly caused infection? I had one little demon fruit fly crash into my rehydrated yeast this weekend and instantly drown I pulled him out, but pitched the yeast anyway. I had no other yeast option other than bread. Its a Saison fermenting at 75. Fermentation was active in only 3 hours.
Surprisingly, the fruit flies are avoiding my carboy.

So you knowingly pitched a vinegar fly into your wort? Sorry, but there's no way I would do that! They're covered with acetobacter.
Just one fruit fly will instantly give a funky taste to a glass of beer. I drink from a lidded stein in fruit fly season.

But acetobacter requires oxygen, so assuming fermentation starts quickly and oxygen is kept out after - one fruit fly probably won't have an effect. I'm suspicious about one fruit fly turning a glass of beer funky. That one might be all in your head. There just isn't enough time for acetobacter to turn beer unless it sits for a few days.

I'm not saying it's a big concern, but I wouldn't do it. That fruit fly would, at the very least, be in my head right down to the last pint. I certainly wouldn't repitch the yeast!
And I have noticed an off flavor halfway through a beer only to discover a fruit fly upon further inspection. My wife and several friends have also noted this phenomenon.

I'd use the yeast. You will out compete any funky if it's a starter. I probably wouldn't reuse the yeast.

As far as "one fruit fly getting in your beer causing an off flavor" .... I'm just gonna say that has to be in your head. There is no way a beer can get infected that fast. I'd be willing to do a taste test with you to see if you could pick out the "funky" beer.

In the name of science I took your challenge. Three plastic cups were filled with about 2 oz Yeungling lager. Hey, it was free! Now I needed to catch a fruit fly in one. No problem. I'll just place it next to the fermenting hot sauce ala Euge on the countertop. The fruit flies seem to love whatever funky aromas are coming from that stuff! Well they love it too much. After 10 minutes a cup of Yeungling 1" away can't attract them. Got figure. Fruit flies prefer rotten vegetables over Yeungling. So after a lengthy hunt I manage to swat one and put it in my beer. After 5 minutes I gave it a stir and fished the fly out.
With my wife's assistance, I did a triangle test. There was clearly a difference and I picked the fruit fly beer 2 out of 2 times as the "rounder" beer. But I don't think I would pick it out if I wasn't looking for it. My wife could not find a difference. Whaddaya know? It was more or less in my head. Now I need a homebrew to wash the Yeungling out of my mouth.

Offline klickitat jim

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Re: Fruit flies in airlock
« Reply #22 on: October 10, 2013, 05:29:58 PM »
Are you sure they are fruit flies? Seems like good hot sauce would attract mosquitoes. Try holding an over ripe banana about 1/16 of an inch over the test sample for an hour. Its what I'm normally doing when fruit flies get in my beer.

Offline beerstache

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Re: Fruit flies in airlock
« Reply #23 on: October 14, 2013, 02:49:48 PM »
Thanks for all the interesting responses.  I'm not too concerned about contamination as the primary ferm. was almost finished and the alcohol present would probably inhibit any funky growths, hopefully! 

Offline morticaixavier

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Re: Fruit flies in airlock
« Reply #24 on: October 14, 2013, 02:53:41 PM »
Thanks for all the interesting responses.  I'm not too concerned about contamination as the primary ferm. was almost finished and the alcohol present would probably inhibit any funky growths, hopefully!

still worth keeping it away from air. aceto bacteria eat alcohol and turn it into vinegar.
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