I've done some experimentation in my time, and in my experience fruit flies positively love actively ongoing fermentation! So I've settled one a mixture with su

I've done some experimentation in my time, and in my experience fruit flies positively love actively ongoing fermentation! So I've settled one a mixture with sugar and yeast in addition to water, surfactant and vinegar or cider. Also, trapping the little bastards is more efficient if you cover the container with cling foil and poke a hole in the middle. They'll easily get in by following the gradient of the escaping molecules, but finding the exit seems to be so much more difficult.