🧺 Flour Mites, Beetles & Weevils — How to Spot Them and Stop Them
Simple steps to reclaim your kitchen from unwanted guests
If you bake regularly, you probably know the feeling: you reach for the flour or a banneton, only to find tiny creatures scuttling about. They might be barely visible mites, slow-moving weevils, or quick little beetles.
These pests thrive in warm, humid conditions and can quickly spread through cupboards, bannetons, and flour sacks if left unchecked.
The good news is that with a bit of vigilance and heat, you can get rid of them effectively.
🐜 1. Meet the Culprits
Flour Mites (Acarus siro)
Size: Microscopic — you’ll usually see a moving “dust” rather than distinct insects.
Colour: Pale, almost translucent.
Habitat: Damp flour, banneton cloths, or wooden storage in humid kitchens.
Signs: Flour develops a slightly sweet, musty smell; bannetons may have a fine moving layer.
Flour Beetles (Tribolium spp.)
Size: 2–4 mm, visible to the naked eye.
Colour: Reddish-brown to black.
Habitat: Dry goods (flour, cereals, nuts), warm pantry shelves.
Signs: Adults crawl inside or outside bags; flour becomes dusty and clumped due to larvae activity.
Grain & Rice Weevils
Size: 2–5 mm.
Colour: Dark brown or black.
Distinctive Feature: Long snout.
Habitat: Stored grains, rice, pasta, and flour.
Signs: Tiny holes in grains, adults wandering around shelves or floors.
🧼 2. Eliminate the Source
Inspect everything.
Check flour, cereals, polenta, dried beans, spices, and banneton cupboards. Infested items must be thrown away immediately.Clean cupboards thoroughly.
Vacuum shelves, corners, and cracks to remove insects and eggs. Wipe down with vinegar or mild soapy water. Avoid strong chemicals — they’re unnecessary and can linger.Don’t forget bannetons and cloths.
Mites and beetles can hide in fabric folds and wood grain.
🔥 3. Use Heat (or Cold) to Kill Eggs and Insects
For bannetons, cloth liners, and wooden tools:
Oven Method: Place in a preheated oven at 90 °C for 30 minutes. This is hot enough to kill mites, beetles, and their eggs, but won’t scorch wood or linen.
Freezer Method: Alternatively, seal in a bag and freeze at –18 °C for 48 hours.
For flour or grains you want to keep:
Freeze unopened packets for 48 hours to kill eggs before storing.
Or keep flour in the fridge for longer-term storage — this is especially useful in warm or humid climates.
🏡 4. Prevent Reinfection
Store in airtight containers. Glass jars or sturdy plastic boxes are ideal.
Keep humidity low. Good ventilation and occasional airing of cupboards makes a big difference.
Adopt a “first in, first out” policy. Use older flour first to avoid long storage times.
Check regularly. A quick inspection every few weeks is easier than a deep clean after an outbreak.
✨ Final Thoughts
Flour mites, beetles, and weevils are a nuisance — but they’re not a sign you’ve done anything wrong. They can arrive in perfectly sealed bags of flour from the mill. The key is to catch them early and deal with them decisively.
A combination of thorough cleaning, heat treatment, and good storage habits will keep your baking space clean, your flour fresh, and your bannetons ready for the next loaf.