Sourdough Starter Tips: Keeping Fruit Flies Away

Sourdough bread has been cherished for centuries due to its unique taste, texture, and health benefits. A key component of sourdough bread is the sourdough starter – a fermented mixture of flour and water that serves as the natural yeast for the bread. However, if you’ve ever maintained a sourdough starter, you may have noticed an unwanted guest buzzing around: fruit flies. 

Fruit flies are attracted to the sweet and fermented aroma of the starter. To keep fruit flies away from sourdough starter, store it in a container with cheesecloth as a cover. As a last resort use a tight-fitting lid. Refrigerate when not in use. Ensure kitchen cleanliness, promptly dispose of ripe produce, and consider placing a DIY fruit fly trap nearby. 

1. Keeping the Lid Closed

a. Employing Fine Mesh or Cheese Cloth for Protection

While it’s beneficial for a sourdough starter to breathe, protection against fruit flies shouldn’t be compromised.

Fine Mesh Covers available in many kitchen stores, allow air circulation while keeping pests out.

Alternatively by using multiple layers of cheesecloth increases the effectiveness of the barrier against fruit flies. It’s crucial to secure it tightly using a rubber band or string.

This method ensures your starter gets the oxygen it needs. The thick mesh acts as a physical barrier, preventing fruit flies from reaching the starter.

b. Sealing the Jar – Choosing a tight fitting lid

While a cloth or loose lid permits the starter to breathe, it may still allow access to fruit flies. A tight-fitting lid acts as a complete barrier against these unwanted guests.

This reduces the chances of contamination from external sources. A sealed environment can provide more consistent results in the fermentation process.

If concerned about gas accumulation, slightly loosen the lid occasionally, or “burp” the container daily to release gases. This ensures safety without compromising the protection.

2. Cleaning the Sourdough Starter Jar

A clean environment is less inviting to pests. Leftover residues on the jar can become a magnet for fruit flies. After feeding the starter, ensure to wipe down any spills on the outside of the container.

Regularly check the surrounding area and keep it crumb and spill-free. A clean environment minimizes the allure for fruit flies.

3. Refrigeration

The design and function of refrigerators have made them more than just cold storage for our food. Their insulated construction and rubber-sealed doors ensure an environment largely cut off from the external world. This isolation not only helps maintain a consistent temperature but also acts as a barrier against pests, including fruit flies.

If you’re not using the starter daily, store it in the refrigerator. Feed the refrigerated starter once a week.

Before baking, remove it 24 hours prior and let it reactivate at room temperature.

4. Implementing a Fruit Fly Trap

By attracting fruit flies away from the starter and trapping them, the overall fly population near your starter is reduced.

DIY Trap Instructions:

  • Take a glass jar and pour in some apple cider vinegar.
  • Add a few drops of dish soap and gently mix.
  • Pierce a few holes in the lid of the glass jar before closing the jar.
  • Place the jar near the starter. The aroma of the vinegar lures the flies, while the dish soap traps them, preventing escape.

5. The Importance of Proper Produce Storage

Fruit flies have a keen sense of smell, allowing them to detect the aromatic compounds released by ripening and fermenting fruits and vegetables.


  • Refrigerating Ripe Produce: This not only prolongs the freshness of the fruit but also minimizes the aromatic compounds that attract flies.
  • Timely Disposal: Decaying produce should be discarded promptly. This limits the food sources for fruit flies and reduces their incentive to reproduce.
  • Regular Bin Maintenance: Cleaning compost and trash bins regularly can drastically reduce the breeding ground for fruit flies. Using bin liners and ensuring bins have tight-fitting lids also help.

6. Keeping the Kitchen Clean

Fruit flies are not just attracted to overripe fruits; they also thrive in environments where food residues are present.


  • Wipe down counter daily: Using a kitchen cleaner or a vinegar-water solution, ensure counters are clean and free from food splatters.
  • Clean your sink regularly: Food residues in sinks provide a feast for fruit flies. Regularly rinsing and occasionally using a drain cleaner can help.
  • Wash the dishes: Avoid leaving dirty dishes out overnight. If you must, rinse them to remove food residues.

7. Ventilation: A Natural Deterrent

The Fruit Fly Dilemma: Fruit flies, despite their agility, can struggle in strong air currents, which can deter them from settling and laying eggs.


  • Fans: A strategically placed fan, especially near windows or where you store your starter, can disrupt fruit fly activities.
  • Regular Airflow: Opening windows, especially during the cooler parts of the day, can help exchange indoor and outdoor air, pushing fruit flies out.


Sourdough starters are a delightful component of the baking world, but they can unfortunately attract pesky fruit flies. By implementing the aforementioned preventive measures, you can maintain a healthy, fruit fly-free starter. Your sourdough creations deserve to be crafted in the most pristine conditions, and with a bit of vigilance, they can be.


Hey there! I'm Sam, your go-to pal for all things sourdough. I've been baking and kneading for 10 fun-filled years, and I can't wait to share the joy of turning simple ingredients into heavenly sourdough bread with you. Grab your apron and let's dive into this amazing world of sourdough bread together on this blog.

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