Fruit flies are a common bane of a kombucha brewer’s
existence. The little guys really can’t seem to help but be
attracted to your first fermentation vessels. It’s not a sign
that anything’s going wrong with your process, so you don’t
have to worry about that — but they can be very annoying.
So here are some tips with dealing with and getting rid of
those pesky bugs.
First things first, make sure that your first fermentation
vessels are covered by a breathable, but fine-weave cloth.
Bandanas, clean cotton and even coffee filters work well.
This will allow your kombucha to “breathe” (that smell is
what attracts the flies so much), but the cloth should do a
good job of making sure the insects don’t come into contact
with your brew.
Make a kombucha “trap”
In a small vessel, pour a small amount of kombucha (flavored or unflavored doesn’t matter) and a small swirl of dish soap. The flies will be attracted to the kombucha, land in the liquid and have a hard time getting out, so they’ll drown.
Some brewers don’t bother with adding the dish soap since the flies very often just drown in the kombucha itself. You can also put some plastic wrap over the container with a few holes poked in it. The flies will find their way in but have a hard time getting out.
Up to you whichever method you want to go with. Just clean the container out and repeat as necessary.
Vacuum up large infestations
I once had a particularly large infestation. I think a momma fly laid eggs somewhere in my home and all her babies flocked to my kombucha vessels. In that case, I just kept my vacuum near my brew vessel and periodically throughout the day, I’d use the hand-held portion to vacuum up the flies. At any given moment, there were over a half-dozen flies perched on my vessel, but by the end of the day, the infestation was all vacuumed up.
Avoid citronella candles, sprays or other insect repellents.
If they’re in close proximity to your brew vessels, the odor or the chemicals may seep into your kombucha. Not yummy.