After about a month of testing a vinegar and sugar syrup for feeding my bees, I have made some revisions to my formula. I noticed that if I added too much vinegar, it did not kill the bees, but it did discourage them from eating the syrup. At first I tried 1 cup of 5% acidity (50 grain) distilled white vinegar in 1 gallon of sugar syrup. However, after further experimentation and observation, I found that between ½ and ¾ cup per 1 gallon of sugar syrup is ideal. Just replace the ½ or ¾ cup of the water in your sugar syrup with the vinegar (1:1).