Those PESKY fruit flies!

[crushday]

Let's have the definitive conversation on our winemaking nemesis - the FRUIT FLY! Looking at this picture turns my stomach... (below)

How detrimental are these little guys to our work in the winery? How about the vineyard? Lot's of vineyards have half eaten, busted, split or otherwise damaged, grapes hanging right on the vine. Let's go ahead and install a neon blinking "OPEN" sign and invite them in... How did the ancients deal with them? I've heard (and read) just one can ruin the finest of wines but then I've seen many open vessel fermentations where nary a caution was employed. Are they REALLY that BIG of a deal?

What say you...?

 

[vinny]

I asked this question because I read that just one can ruin an entire batch of wine.

The answer that I have accepted is that yes a single fruit fly COULD ruin an entire batch by introducing acetobacter, but there are many other variables that need to be in place for it to happen.

Number one being oxygen. It is required in the second stage where alcohol is converted to acid. So if we follow proper procedures and keep O2 out of our wine, it should never be possible.

I, like many here, have had fruit flies get into my primary, but I have been lucky enough to date that I have not experienced a spoiled wine.

 

[CDrew]

For basically the first time ever, I had a few fruit flies hanging out when I pressed Syrah last week. I didn't see any get in the wine, but I had several hanging out on a stopper that was overflowing a bit of wine. I drowned them with star san!

My take on it is that acetobacter are everywhere (likely on the grapes already) and don't need fruit flies to get into your wine. And even if it does, it's going to take awhile to ruin the wine, and by then, O2 has been excluded, sulfites added and the like, which inhibits acetobacter and acetic acid formation.

A few years ago one of the east coast guys showed photos of thousands of fruit flies in the wine making area. Those kind of numbers might influence the wine, but even then, good practices are mostly going to limit the damage done.

Now regarding the ancients, I'll bet a lot of terrible wine was produced and consumed! Whether fruit flies were the problem, I don't know, but the germ theory of disease was not known, and there were no sanitary practices, yet, they carried on and made wine anyway!.

 

[sour_grapes]

For input to a definitive conversation, I think you could review this post by a new member, @yeasty_boy . He makes some good points:
On the footsies of vinegar flies

 

[winechef]

I use mosquito netting to cover my tanks, I don't see them as a problem, clean your area well, no residual juice on counters, equipment, floor, clean. well and it's not really an issue. I've had one or 2 floating dead during fermentation, just remove ASAP,

 

[Hazelemere]

I trap them with cider vinegar containers covered with slightly punctured saran wrap with a drop of palmolive dishwashing liquid in each trap. It works perfectly.

 

[Clover]

I ferment in my kitchen, and this late summer they have been awful. Having little to no success with a traditional vinegar/wine and dish soap trap, bleach down the sink drains, etc., I bought a trap that is a UV light and fan that sucks them down into a sticky trap. However, my trap also has a bug zapper at the top. The sound of those bugs hitting the zapper is satisfying, I must say. My dog hates the sound, though, so we run it at night when we're asleep for the most part. It has significantly reduced the flies since I bought it.

 

[balatonwine]

How detrimental are these little guys to our work in the winery? How about the vineyard? Lot's of vineyards have half eaten, busted, split or otherwise damaged, grapes hanging right on the vine.

I do not worry too much what happens to grapes in the vineyard from natural factors (other than major pests that can kill or destroy a crop such as fungus). The world is a messy, dirty place. Yet we survive it.

But once one harvests... That changes the equation. Then I start to inject my desires onto the fruit and Ideally only use pristine fruit. Especially if one if using "spontaneous" fermentation and do not pitch commercial yeast.

Else, and the world is messy, if not pristine fruit, I have found the proper use of chemicals like KMeta on damaged grapes kill off most of the bacteria that causes problems from fruit flies at crush time. And have had few issues that I can directly blame on fruit flies.

I've heard (and read) just one can ruin the finest of wines

What scale are you referring to?

I am one who can taste if one fruit fly has fallen into my glass of wine. They taint the wine for me. I can taste that one fly in my glass. (Cross reference this Wine Spectator post)

But to claim one can ruin a vat of wine, would need some actual experimental evidence before I would take a claim seriously. Anecdotally, I have not experience this if I found a fruit fly in the wine when racking a vat.

Are they REALLY that BIG of a deal?

I think they are a concern in the wine cellar. As they can impact some wine. And so any action taken to limit their impact should be employed. Especially since such actions are rather easy to employ. But I do not go to extremes. If I have wine faults, they are usually caused by other factors.

Hope this helps.

 

[Rotundifolia]

Using a shop vacuum to suck up the FF is a fun sport. But mainly I use a box fan when opening up the top. It is an old Florida trick to keep noseeums away

 

[QuiQuog]

Using a shop vacuum to suck up the FF is a fun sport. But mainly I use a box fan when opening up the top. It is an old Florida trick to keep noseeums away

Please explain this Florida trick

 

[Rotundifolia]

Small flying insects don't have the wings to fly against the wind. So as long as the air flow is over your brute it will keep them from coming into the fermentation vessel. In Florida we uses small stand up fans when sitting outdoors and did not have a problem. Obviously would not work for larger parties of people.

 

[hawkwing]

Using a shop vacuum to suck up the FF is a fun sport. But mainly I use a box fan when opening up the top. It is an old Florida trick to keep noseeums away

I have way better success using a vacuum as well. Traps just don't catch many. There are so many around outside right now especially in the compost bin where I dumped the stems. A few times there were clouds of them outside and when I open the door many dozens come in. They like to land on the mirror in the bathroom as well as on the traps in the kitchen. The traps work better as lures to vacuum them up than to actually get them.

 

[Rotundifolia]

Completely agree traps are best. But even with traps I see those pesky flies siting on top of my cover on the brute in my part of the country, seemingly laughing at me. This is where it is somewhat satisfying sucking them up with a vacuum. Perhaps I am a little sadistic