This is my first time catching some wild yeast. A while back I took some extra wort from my sparge, put it in a mason jar, and left it outside for a few days until it started to bubble. Then I put the jar in my brew room for about 5-6 weeks, until I was ready to brew (hoping it would sour up a bit). I tasted it every now and then to make sure it didn't taste terrible. I made a starter, let it do it's thing for a few days, and pitched. Fermentation went great, racked to secondary after 2 weeks, had a good taste with a nice tart/fruitiness to it.
Now, after being in the secondary for a little over a week, I noticed a pellicle is forming. I'm fine with this, I'm just curious as to what's going on. I did a little searching about pellicles, but couldn't find much information about what causes them, or what to do with them.
Do I wait until it drops out before the beer is ready? I guess that's my main question, but any links to the science would be greatly appreciated.