While we enjoy the benefits of summer such as backyard BBQ’s, warm weather, and the beauty of nature’s bounty there is a downside. Yes, those dreaded insects. Mosquitoes may drain us of a pint of blood or two, wasps may liken us to a piece of steak, but winemakers must be aware of another summertime pest, the dreaded Melonagaster Drosophila. No, not the latest dinosaur discovery, far from it, this pest is the common fruit fly.
Fruit flies are actually poorly named. They should be named Yeast flies, for it is yeast that they actually seek. So when you have ripened fruit, particularly bananas you have yeast. And guess what also has yeast! Your wine!
While some may be able to tolerate a few dead flies that is not the end of the problem of this pest for winemakers. The Fruit fly relies on a bacteria species in its stomach to digest the yeast. The name of these bacteria is acetobacter, and it is a bacteria you should fear! Acetobacter loves alcohol! It breaks down alcohol and makes ----- Vinegar!!! In fact, that’s how vinegar is made, using commercial preparations of acetobacter, known as Mother of vinegar.
So if you have Fruit flies doing the back stroke in your wine, their little tummies may rupture spilling acetobacter into your precious wine. Voila! Do you like vinegar on your fries? Acetobacter makes your wine smell like nail polish remover and taste like vinegar. Yum Yum, huh!
So, now that we have scared you about fruit flies, how do we protect our wine from the summer plague of Fruit flies? Cleanliness! Clean up any spilled wine, throw away filter pads (a smorgasbord for Fruit flies). Treat all surfaces with sulphite solution. Sanitise all of your equipment with Chlorinated cleaner (the pink stuff). Makes sure your airlocks are filled with water and secured.
If you have a fruit fly problem, you may want to consider building a Fruit fly trap. You can construct one out of a 2 l pop bottle, similar to a wasp trap. Bait it with Cider vinegar. Or make a paper funnel and place in a large yogurt container with the narrow end near the bottom of the container. Pour ½” of Apple cider vinegar in the bottom. Fruit flies love Apple cider vinegar.