So I decided to start making starter cultures.
I built a stirrer out of a computer fan. I am assuming that the reason for using a stirrer, as opposed to just letting it sit stagnant, is so that the yeast has plenty of oxygen to multiply, yes?
Anyway, after a few hours my starter culture grew a foam on top. Now, it occurs to me that this foam is bubbles of C02, and since the foam covers the entire top of my culture, it is now starved of oxygen again
Do people worry about this?