Pitched a tube of WLP to my starter wort last night and dropped it onto my brand new stir plate. This morning I woke up to a thick, creamy, beautiful krausen layer, about 1/2" thick. The vortex has disappeared under it. Came home this evening, and it smells wonderful. Krausen is still there, stir bar still chugging away happily I'm not telling you what I'm planning this weekend, but I did pick up 5 LB of Wheat DME and 1 LB of Munich.
Question: with the stir bar moving, will the krausen drop? how will I know when the starter wort is exhausted? I assume the stir bar will prevent the yeast from flocculating, which has in the past been my que to cold crash and harvest.