Greek taverna owners have a simple, cheap method to keep wasps away from outdoor dining tables: smouldering ground coffee. This natural, chemical-free repellent costs just 15.9p per use and can clear patio tables in seconds.
How the trick works
Wasps use a strong sense of smell to locate sweet foods and meat. Ground coffee contains natural compounds and caffeine that release a pungent, bitter smoke when smouldered. This aroma masks the scent of food and overpowers the insects' senses, creating an invisible shield around the table that wasps refuse to cross.
Only dry ground coffee works—either fresh from the bag or spent grounds thoroughly dried in the sun. Instant coffee granules will not work as they melt rather than burn.
Cost and preparation
A standard 227g bag of supermarket ground coffee costs around £3.50. Each table treatment needs roughly a 10g scoop, costing 15.9p per use. If you save and dry out morning espresso or filter coffee scraps, the hack costs nothing.
To prepare, place two or three heaped tablespoons of dry ground coffee into a small pile. If using leftover grounds from a cafetière, ensure they are bone-dry first. Choose a heat-proof vessel, such as a small metal dish, ceramic bowl, foil tray, or an empty, thoroughly washed tin can.
Lighting and placement
Place the vessel on a heat-resistant surface near the edge of the outdoor table. Hold a match or lighter to the peak of the heap for a few seconds. The coffee will not burst into flame but will slowly catch fire and smoulder like a stick of incense.
This trick must only be used outdoors in open-air spaces. Keep smouldering dishes away from pets and small children, never leave them unattended, and always extinguish the ash with water once you finish dining.
Other pest-repelling scents
Coffee grounds also work against other summer pests. Baking coffee grounds in the oven for 15 minutes can banish houseflies from your kitchen for up to three hours. Rolls of roasted cinnamon can be effective, though they may make your home smell like Christmas in August. Boiled orange and lemon peel releases limonene, a fruity air freshener that flies dislike.
