“Curses, I can’t get RID of the things,” griped my local bartender. “I keep the lemons in tupperware, and anything else in the fridge-- yet they STILL hover over my workspace, especially near the taps! What to do?”
I’m guessing that they’re breeding in spilled beer around the taps. Tell him to clean the whole bar really well.
The area where the kegs are stored needs to be C-L-E-A-N-E-D, big time. I worked in a bar for a long time, a real dive, I must say. One afternoon, I needed to replace a keg and as I opened the cabinet I was attacked by a swarm fruit flies. When I removed the empty keg there were puddles of fermented beer all over the cabinet floor. They apparently thrive in this envioroment.
If there is a beer drain this should be cleaned as well.