Fruit Flies and Kombucha

Like us, fruit flies love kombucha. Learn why and what can be done to prevent them from ruining your homemade kombucha

You may have noticed that fruit flies are be attracted to kombucha. Fruit flies are attracted to the smell of anything fermented or fermenting (such as rotting fruit, beer, vinegar and kombucha), so you may find them congregating near the top of your fermentation jar hoping for a taste!

What Are Fruit Flies?

Fruit flies, also known as gnats, barflies, vinegar flies, drain flies or pomace flies, love kombucha. They are drawn to the aromas produced during the fermentation process. You might even see some resting on the top of your fermentation jar–this is OK. If you’ve noticed fruit flies around your kitchen, you will want to take a few simple precautions to eliminate these pests and ensure they don’t find their way into your kombucha.

How to deal with fruit flies

The first defense to keep fruit flies out of your kombucha is to reduce the population of fruit flies. as much as possible. Make (or buy) some fruit fly traps and place them around your kitchen. Here are some simple yet effective traps you can make at home.

Vinegar and soap trap: In a small cup or bowl, mix some kombucha with a small amount of dish soap. The kombucha may be substituted with just about any vinegar, fruit juice, wine, cider, or beer. The flies will be attracted to the kombucha and land in the liquid. Once in the liquid, they will have a hard time getting out and subsequently drown. You may make it without the dish soap, but it helps keep the flies trapped in the liquid.
Plastic-wrap trap. Similar to the kombucha trap with the additional step of covering the vessel with plastic wrap and poking small holes in it. The flies will find their way into the container through the small holes and won’t be able to find their way out. This can also be done with a mason jar with some nail holes in the top.
Funnel trap: Pour a small amount of kombucha (vinegar, fruit juice, wine, cider, or beer) Set a funnel (or coffee filter with the tip cut off) over the glass. The flies are attracted to the liquid in the glass and won’t know how to get out. This can also be made by cutting the top off a recyclable water bottle, removing the cap and inverting into the bottom of the bottle.
Wine Bottle Trap: Leave some wine in the bottom of a bottle and place it on the counter. Fruit flies will fly in and be confused by the bottleneck and not easily find their way out.
Fresh Basil: Fruit flies don’t like fresh basil and keeping a potted plant of basil on the counter will deter them. When brewing or bottling pluck a few leaves from the plant and scatter around the area. Bonus – it’s great to have on hand for cooking!
Store Bought Traps: I use these traps from Terro (affiliate link ↗) and refill with vinegar or beer when the provided solution is gone.

How to keep fruit flies away from kombucha?

Keeping flies out of your kombucha typically is not an issue, you simply need to keep your kombucha brew covered. Ensure that the material you are using to cover your kombucha jar has a tight enough weave to prevent fruit flies from getting in. Some cheesecloths don’t have a tight enough weave to keep them out. This can be fixed by doubling or tripling the cheesecloth over the jar. Coffee filters, layer of paper towels and tea-towels also work great.

How to keep fruit flies away when bottling

You are about to bottle your latest batch of great kombucha and notice some pesky fruit flies hovering around. Here is what you can do to minimize the risk of them getting into your kombucha:

Vacuum: If there are fruit flies sitting on top of your brew jar you can use the hose attachment of your vacuum and suck them up

Blow them away: Point a small fan toward where you are working . The fruit flies will struggle to overcome the breeze

Move quickly: If you only notice a few fruit flies, simply work quickly. Remove the cloth covering from your fermentation jar, pour the kombucha into a waiting bottles and quickly replace the cloth covering.

Fresh Basil: As mentioned above, fresh basil will deter fruit flies from coming near the area.

What to do if your kombucha has fruit flies in it?

Finding fruit flies in your kombucha can be upsetting. If you have an infestation, unfortunately, your best bet is to start over as the larvae could be present on the pellicle itself. However, it may be salvageable

You Have a SCOBY Hotel – If you have a well-stocked SCOBY hotel you can just throw away the batch of Kombucha and use a SCOBY from the hotel. To ensure you don’t contaminate the next brew you will need to thoroughly clean the Kombucha vessel.
Multiple or thick layers of SCOBY – In this case you can remove the top layer or layers of SCOBY and compost them. The SCOBY acts as barrier against the fruit flies which can’t get through to the bottom layers and into the Kombucha.
Attempt a salvage: If your SCOBY is fairly thick (greater than 1″) it is unlikely that the fruit fly was able to penetrate deep into the pellicle. Carefully remove the SCOBY and peel off the top layer and compost. Rinse the bottom layer very well and it back to the fermentation jar.

Wait about a week and examine the brew for any traces of flies or larvae. If you still see traces of an infestation, discard everything. If not you are fruit fly free!