I want to try culturing a sourdough, which seems like a complex thing, as it's apparently a symbiosis between a yeast and a bacteria. To capture a wild yeast seems like a good start. One method I've read about involves collecting rainwater and mixing this with flour. Another method is to simply mix flour and water and then let this sit outside for a few days. I'm currently trying both of these. Other methods call for soaking various edible and inedible things in a very watery dough. I'm also trying to make some sauerkraut. My last batch turned moldy, but with this one I'm going to be scrupulously clean. There are two methods. One involves coating the cabbage in salt, the other by submerging in a light brine solution. I thought that with Riley a fun project would be to inoculate petri dishes with bread yeast, wine yeast, wild yeast, etc... and then to try looking at them through a microscope. This would ultimately be the only way of identifying whether I had captured a real sourdough or just a wild yeast.