Originally Posted by jburtner
It's gelatinized lees, pulp, and material? I googled something like "cider floating sponge" and it appears to be byproduct of a process called keeving. Lots of pictures and this looks exactly the same. From what I read folks trigger this reaction maybe with a calcium chloride addition in cider making but generally early on or before fermentation. It binds up nutrients in order to slow the ferment and maintain a sweet finish? Hmmmm. I was trying for the opposite - there is still significant bubble activity in the must because it's making this cap float.
It's almost like a clearing agent has been added but ferment makes it float. Dead yeast lees are on the bottom so this is slightly different.
I did a little research, interesting process. One of the key "ingredients" for keeving appears to be extended periods of temps at 5 degrees C. Assuming you haven't been chilling your carboy for a week, it doesn't sound like you've happened along into that process.
It sounds like it's fermenting, which is what you're shooting for, have you tried to stir that glob back into the wine or does it just keep forming?