Can anyone explain what would cause my yeast starter to have a “oil slick” like swirls on the surface of the wort? My starter has been crashing for 2 days now and i was getting ready to step the starter up and i noticed this and im wondering what its is, i clean and sanitize thoroughly, could my environment not be sanitary enough and contamination makes it through my process? i would post a picture but its not visible on a picture but it person you can clearly see swirls on the surface, whenever i see something like this i dont want to take the chance and brew with it, does anyone know what this could be and should i just scrap this starter and order a new pack?
Did you use Fermcap (or other antifoaming agent) when preparing the starter? I use it all the time for my starters without issue, but occasionally I do see small blobs or a bit of a film floating on the starter.
No i did not add anything, but i do think it was just some residual star san, i went ahead and proceeded with the next starter step