Slightly OT, but Eastern Europeans make Kvas - it's based on dried up bread (sometimes honey) and bread yeast.
Makes a nice summer drink, about 2-3% ABV, sometimes less.
I'm tempted to try this but with weatbix since I have a pile of Cooper can yeast
With a lot of girls wearing g strings or no panties at all these days you would probably require quite a few visits from your girlfriend to harvest enough yeast to pitch with, and using a pair of a sister's or mother's to boost the yield just wouldn't be right, unless of course you live in Deliverance territory. If you could get hold of some old style granny undies and have your girlfriend wear them for a week or two you would probably be okay to pitch with them, but your girlfriend would really have to be sick dedicated to you to put herself through such an ordeal. You might be better served straining a hand sanitiser or any such alcohol based cleaning product through slices of bread and just drink that. In the old days they did this with boot polish, but that's no good now with everyone wearing thongs and runners, and the screws would be onto you instantly if you wore leather shoes and they were still dirty and scuffed up as you lay on your bunk watching MacGyver on tv. Sorry I can't be more helpful than that