I've always fermented in a plastic bucket. Recently I purchased a 6 gallon betterbottle to use for a Primary..
So I've never been able to see the primary fermentation action!!
This is the first time I've used it and I noticed after about 3 days when fermentation had settled down, there's a ring of white bubbles around the edge as you can see in the pic below..
So is this starsan that has sucked back into the carboy from my blow off tube?
Or is it something else that I need to be concerned about?