Vinegar flies, sometimes inaccurately called fruit flies or bar flies, are small flying insects and yellowish brown to dark brown in colour. They can become a pest in homes, cafes, restaurants, pubs, bars, fruit markets, etc. Vinegar flies are often seen hovering around overripe fruit and vegetables, baked goods containing yeast, rubbish bins, unclean mops and dishcloths, drainwater, and around beverages such as fruit juices, cider, soft drinks, beer, wine and vinegar.
Vinegar flies are attracted to the yeasts found in fermenting substances. Vinegar flies will breed in any soured, decaying substance such as those described above as well as wet mops and accumulations of food particles behind or under kitchen equipment. Drains, which have a gelatinous growth of scum, can also support an infestation of vinegar flies.