When I make a stock, I generally skim the foam for the first few hours, and usually it stops showing up. But as I've increased my cooking time, I've started to see a clear skin forming on top of the stock. Usually around 14-24 hours in. Unlike the foam it's pretty difficult to skim out as it wants to stick to the meat, vegetables and herbs floating at the surface.
I tasted some of it and it didn't have a terrible flavor. Mostly just tasted like the fat floating on the stock. What is this stuff, and is it ok to ignore?