I've been working on harvesting some yeast from a commercial hefeweizen for the last week or so.
A few days back I noticed some opaque white stuff on top of the wort in the 500ml bottle I started out with. Shortly afterward a nice clean foam started appearing on top of the starter, and I stopped worrying.
Yesterday I stepped up to a 1L mason jar. The jar and the foil on top were both boiled for 45 mins (thus the colour of the foil) and the lip of the bottle containing the starter was flamed before transfer. The wort inside was 1.050 gravity and lightly hopped.
This morning I noticed opaque white blobs floating in the starter. They occasionally sink when I swirl the jar:
Is this likely to be an infection, or just the yeast manifesting itself in a slightly different way?
The sniff I took of the bottle after I'd transferred seemed to smell fine, but I'm still a bit concerned. Is there some way I can know with greater certainty before pitching this into my full sized wort?
Thanks very much for your help.